[From the U.S. Government Printing Office, www.gpo.gov]




                                                                                     2, 'D-



                             MYAKKA RIVER BASIN PROJECT/
                       A Repo**r*t on Physical and Chemical Processes
                   Affecting the Management of the Myakka River Basin

                 (Provisional Results from January 1989 - December 1989)






                                      Susan S. Lowrey
                                    Kimberly J. Babbitt
                    Jeffrey L. Lincer, Ph.D., Principal Investigator

                       Sarasota County Natural Resources Department
                              Ecological Monitoring Division
                                    1301 Cattlemen Road
                                  Sarasota, Florida 34232




         a-                       Steven J. Schropp, Ph.D.
         V-                            Fred D. Calder
         no
                      Florida Department of Environmental Regulation
                              Coastal Zone Management Section
                                    2600 Blairstone Road
                                Tallahassee, Florida 32301
                                                                     COASTAL ZONE
                                  Herbert L. Windom, Ph.D.       INFORMATION CENTET4

                                   University of Georgia
                            Skidaway Institute of oceanography
                                  Savannah, Georgia 31406'



                                R. Bruce Taylor, Ph.D., P.E.
                                        Terrence Hull

            GB                       Taylor Engineering
            991                   9086 Cypress Green Drive
            Y6                  Jacksonville, Florida 32216
            M93
            1990   this project are provided by the Florida Department of Environmental Regulation, Office
                  I Management, using funds made available through the National Oceanic and Atmospheric
                  ation under the Coastal Zone Management Act of 1972, as amended.
    C@l






         U-













                                          TABLE OF CONTENTS


            LIST OF TABLES   .................................................              iii


            LIST OF FIGURES    ..................................................           v


            EXECUTIVE SUMMARY     ............................................          viii


            ACKNOWLEDGMENTS...,,,,,,,,,,..........,..          ...                .......   xii


            INTRODUCTION... o   .................................................           1
                  Project Overview/Purpose       ...................................        1
                  Research and Monitoring Programs       ......   oo ....................   2
                  Description of the Report      ...................................        2

            ENVIRONMENTAL SETTING_ ....
                  General Physiography of the Watershed. .        .....................     5
                  Subbasin Descriptions       .....................................         10
                  Soil and Vegetation Types in the Watershed           .................    15
                  Description of the Estuarine Study Area         ....................      16

            STUDY METHODS    .......................     oo  ....... oo  ................   20
                  Rainfall and Hydrology      .........................     o...........    20
                         Rainfall   ........................      o........... o .........  20
                         Hydrology  ........   oo ................................      _20
                  Storm Hydrographs and Rainfall        .............................       24
                         Hydrograph Development      .............................      @..24
                         Storm I Hydrograph Analysis     ...........................        30
                         Storm 2 Hydrograph Analysis     ...........................        30
                  Water Chemistry     ...........................................           32
                         Sampling Periodicity      .................................        32
                         Station Locations     ....................................         32
                         Sampling Methods and In-Situ Measurements         ............     o35
                         Laboratory Analysis     ........ o  ...................   o  ..... 36
                  Nutrient Flux Analysis       ..............................      o  ..... 37
                         Estimates of Annual Material Flux        ...o .................    37
                         Extrapolation Method for Estimating Material Flux.           ....  38
                         Interpolation Method f or Estimating Material Flux           ..... 40
                         Estuarine Chemistry     .................    o ................    40
                  Sediment Chemistry      ...... oo ......... o   ..................  o ... 43
                         Sampling Locations      ...................................        43
                         Sampling Methods     ................    o................   -.44
            RESULTS.     Laboratory Analysis     .............      .......  ........   _44
                     iW , * *@ a** * , * * * * , * * * * , , * * * , , * * o * , , * , ** * * * * * ,* o ......... 49
                  Ra   fal    nd Hydrological Results       ..............   .........      _49
                         Rainfall   ...........................     o..........  o .......  49
                         Hydrology   .............................................          49
                  Storm Hydrograph and Rainfall        ..............................       49
                         Myakka City (B110)   .............................        o ...... 49
                         Myakka River at S.R. 780 (B130)o         ........o.............    57
                         Myakka River between Upper and Lower Lakes (B140)            ..... 60









                        Myakka. River at Control near Laurel (B160)       ............ 62
                        Howard Creek (B12 0)   ...................................     65
                        Deer Prairie Slough (B170)     ............................    69
                        Big Slough Canal at S.R. 72 (B150)      ....................   71
                        Big Slough Canal at North Port (B180)       .................  75
                  River and Tributary Water Chemistry Results        ................  78
                        Physical Summary    .....................................      78
                        Annual Nutrient Loads    .................................     84
                        Estuarine Water Chemistry Results      .....................   86
                  Sediment Chemistry Results     .................................     88
                        Metals  ................................................       88
                        Nutrients   .............................................      92
                        organics   ..............................................      94

             FUTURE DIRECTIONS    ..............................................       96
                  Report Synopsis   ...........................................        96
                  Future Technical Report     ....................................     96
                        Management Tools    .....................................      96
                        Management Plan    ......................................      97

            LITERATURE CITED    ...............................................        98





                                             APPENDICES

                  Appendix    A     Basin and Estuary Station Descriptions      ....  i..Al
                  Appendix    B     Summary of Longterm Rainfall Data      ........... B1
                  Appendix    C     Summary of Physical and Chemical
                                    Data f rom Basin Stations   ....................   Cl
                  Appendix    D     Seasonal Changes in Water Chemistry
                                    at Basin Stations   ...........................    D1
                  Appendix    E     Summary of Physical and Chemical
                                    Data from Estuary Stations     ..................  El
                  Appendix    F     Monthly Distributions of Nutrient
                                    Concentrations at Estuary Stations      .......... F1













                                          LIST OF TABIAES

          TABLE A. Overview of studies conducted within the Myakka
                       River watershed   .......................................           3

          TABLE B.     Basin names and associated drainage areas         .............  12

          TABLE C.     Salinity values for estuarine stations       ................    18

          TABLE D.     Location, period of record and collection
                       information for long-term rainfall stations          ........... 22

          TABLE E.     Location, period of record and collection
                       information for intermediate and short-term
                       rainfall stations     ....................................       22

          TABLE F.     Summary of information on USGS gaging stations
                       within the Myakka River watershed       .....................    23

          TABLE G.     Summary of monthly discharge (cms) data at six
                       USGS gaging stations in the Myakka River
                       watershed  ............   #...

          TABLE H.     Summary of monthly rainfall (mm) data within
                       the Myakka River watershed. .    ........  o..... oo.o ......   _26

          TABLE I.     Results of storm 1 hydrograph analysis       ...............     o28

          TABLE J.     Results of storm 2 hydrograph analysis. . . . o . . o . . o...  _29

          TABLE K.     Determination of days to peak and fall for
                       selected storm events... . - o  .......              o.....  oo..33

          TABLE L.     Chemical parameters and methods used for
                       analysis.  ......

          TABLE M.     Interpolation methods for f lux calculations. . .                41

          TABLE N.     Dates and location for Myakka River, Peace River
                       and selected Charlotte Harbor sediment sampling
                       stations.....   ..... o.o ....  o.-o-o-o      ......  o-o-_43

          TABLE 0.     organic compounds measured and detection
                       limits for July 1985 (CHH-2) and November 1989
                       (MYK-1, MYK-3) sediment samples.... o      .... o......  o.o  .... 46

          TABLE P.     Summary of dissolved oxygen values at basin
                       sites... .........                       o...........   oo  ...... 82

          TABLE Q.     Rating curve parameters and statistics.. .       ... _..oo     ... 85



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          TABLE R.  Annual fluxes of dissolved and particulate
                    nutrients (metric tons) ............................... 87
          TABLE S.  Metal concentrations (ug g'1) in Myakka River,
                    Peace River and Upper Charlotte Harbor sediments ...... 89
          TABLE T.  Nutrients (ug g-1) in Myakka River, Peace River
                    and Upper Charlotte Harbor sediments .................. 92










































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                                        LIST OF FIGURES

          FIGURE 1.     Location of the Myakka River Basin (after Joyner
                        and Sutclif f e, 1976) .. o . o.....................    o.oo .... 6

          FIGURE 2.     Elevational changes within the Myakka River Basin
                        (from Drummond,, 1977) . o..........   o .................    o..7

          FIGURE 3.     Long-term discharge at the USGS gage at Myakka
                        River State Park (B140)                ....... *......  *......  9

          FIGURE 4.     Subbasin and gaging station locations within the
                        Myakka River Basin   ...................................       11

          FIGURE 5.     Major tributaries of the Myakka River estuary;
                        (a) Curry Creek; (b) Deer Prairie Creek;
                        (c) Warm Mineral Springs; (d) Big Slough        .............  17

          FIGURE 6.     Location of rainfall stations within and near the
                        Myakka River watershed. Long-term stations are:
                        (a) Fort Green; (b) Myakka River State Park; and
                        (c) Venice. Short-term stations at Myakka River
                        State Park are: (1) North Entrance; (2) FPL;
                        (3) Rookery; and (4) Preserve. stations MSI-MS5
                        are on the Carlton Reserve    ...........................      21

          FIGURE 7.     Location of basin and estuary sampling sites         ......... 34

          FIGURE 8.     Concentration-discharge rating relationship for
                        dissolved, particulate and particulate-associated
                        substances in rivers (after (a) Walling and Webb,
                        1983 and (b) Walling and Webb, 1981)       ...............    o.39

          FIGURE 9.     Examples of different estuarine behavior of trace
                        metals: (a) removal (after Figueres et al., 1978;
                        (b) conservative; and (c) release (Windom,
                        unpubl. data)  .......................................         42

          FIGURE 10.    Long-term annual rainfall for (a) Fort Green and
                        (b) Myakka River State Park     ..........................     50

          FIGURE 11.    comparison of mean monthly rainfall for 1944-1989
                        (triangles) with monthly rainfall for 1989 (bars)
                        at Myakka River State Park    ...........................      51

          FIGURE 12.    Variability of rainfall for June through
                        September, 1989 at six site within the watershed          ..... 52

          FIGURE 13,    Seasonal variation in discharge at subbasin
                        stream gaging stations    ...............................      53

          FIGURE 14.    Myakka City (B110) - Storm 1      .........................    54

                                                 v









           FIGURE 15. Myakka City (B110) - Storm 2    ..........          ........ 56

           FIGURE 16.   Myakka River at S.R. 780 (B130) - Storm I    ............ 58

           FIGURE 17.   Myakka River at S.R. 780 (B130) - Storm 2    ............ 59

           FIGURE 18.   Myakka River between Upper and Lower Lakes
                        (B140) - Storm 1  .....................................   61

           FIGURE 19.   Myakka River between Upper and Lower Lakes
                        (B140) - Storm 2 ......................................   63
           FIGURE 20.   Hyakka River at control near Laurel (B160)
                        Storm 1.............................................      64

           FIGURE 21.   Myakka River at control near Laurel (B160)
                        Storm 2.............................................      66

           FIGURE 22.   Howard Creek (B120) - Storm I   ........................  67

           FIGURE 23.   Howard Creek (B120) - Storm 2   ........................  68

           FIGURE 24.   Deer Prairie Slough (B170) - Storm 1    ................. 70

           FIGURE 25.   Deer Prairie Slough (B170) - Storm 2    ................. 72

           FIGURE 26.   Big Slough at S.R. 72 (B150) - Storm 1    ............... 73

           FIGURE 27.   Big Slough at S.R. 72 (B150) - Storm 2    ............... 74

           FIGURE 28.   Big Slough at North Port (B180) - Storm 1    ............ 76

           FIGURE 29.   Big Slough at North Port (B180) - Storm 2    ............ 77

           FIGURE 30.   Seasonal variation in water temperature at basin
                        sites  ................................................   79

           FIGURE 31.   Seasonal variation in pH at basin sites    .............. 80

           FIGURE 32.   Seasonal variation in conductivity at basin
                        sites  ................................................   81

           FIGURE 33.   Seasonal variation in dissolved oxygen at basin
                        sites  ................................................   83

           FIGURE 34.   Sediment concentrations of (a) arsenic,
                        (b) cadmium, (c) chromium and (d) copper.
                        Points within the two outer lines are considered
                        to be within the range for natural sediments
                        (FDER,1988)  .........................................    90



                                              vi









         FIGURE 35.  Sediment concentrations of (a) lead, (b) nickel
                     and c) zinc. Points within the two outer lines
                     are considered to be within the range for natural
                     sediments (FDER, 1988) .......0....................... 91

         FIGURE 36.  TOC and TKN concentrations from (a) natural
                     Florida coastal sediments and (b) Nyakka River,
                     Peace River and Upper Charlotte Harbor sediments ..... 93

         FIGURE 37.  TKN and TP concentrations from (a) natural
                     Florida coastal sediments and (b) Myakka River,
                     Peace River and Upper Charlotte Harbor sediments ..... 95




































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                                    EXECUTIVE SUMMARY




           1.    The Myakka River Basin Project was initiated in 1988 as the
                 fourth state-wide "Estuarine Initiative" implemented by
                 Florida Department of Environmental Regulation's (FDER's)
                 Coastal Zone Management (CZM) Section, with funds made
                 available through the National oceanic and Atmospheric
                 Administration (NOAA).    The objective of the study is to
                 provide a technical basis for holistic, basin-wide management
                 of the Myakka River Basin.

           2.    The Myakka River Basin is a relatively undeveloped area in a
                 region where unprecedented growth projections raise concern
                 over the potential for increased environmental impacts.
                 Little information was available on the river basin and no
                 basin-wide studies had been conducted prior to this project.
           3.    The study area encompasses 1,559 km2 in portions of five
                 counties (Manatee, Hardee, Sarasota, DeSoto and Charlotte) in
                 southwest Florida.   The Myakka River, a meandering 70 mile
                 blackwater river, is the smallest of three main tributaries of
                 Charlotte Harbor, one of the largest and     most productive
                 estuaries in Florida.

           4.    Vegetation near the river goes from hardwood hammock, to
                 oak/cabbage palm hammock, to freshwater marsh, to salt
                 marsh/mangrove plant associations, as one travels downstream.
                 Pine Flatwoods dominate the rest of the basin, with lesser
                 amounts of prairie and improved pasture. Freshwater wetlands
                 are widely distributed throughout the basin.

           5.    Soils throughout the watershed are sandy and poorly drained.
                 Near the river in the upper reaches of the watershed, soils
                 are typically alluvial and sandy with low organic content. At
                 river mile 15.5, a transition to soils with high organic
                 content occurs, indicating the transition from primarily fresh
                 to primarily saltwater habitats.

           6.    Results from the first year (January 1989 to December 1989)
                 are presented in this report. The first year of the project
                 focused on collection and compilation of data on the physical
                 and chemical processes affecting the basin.         Particular
                 emphasis was given to examining the transport of dissolved and
                 particulate nutrients and suspended solids to the estuary.






                                          viii








            7.   Sampling was conducted 17 times at .18 stations.            Eight
                 stations were located in the basin as follows: Myakka River
                 (4), Howard Creek (1) , Deer Prairie Slough (1) , and Big Slough
                 (2).   The remaining 10 stations were located in the tidal
                 reach of the Myakka River (9) and in Charlotte Harbor (1).

            8.   Samples were also collected during 2 storm events to determine
                 if these events produced more efficient delivery of materials
                 to the estuary.

            9.   Drought characterized rainfall conditions in 1989. Rainfall
                 at Myakka River State Park was 253 mm below the mean for the
                 period of record (1943-1989). 1989 was the second consecutive
                 year with rainfall below the long-term mean.        Four of the
                 previous six years have also been below the long-term mean.

            10.  Rainfall/runoff analyses indicate that antecedent soil
                 moisture conditions are important to subbasin retention rates.
                 Low soil moisture results in high retention rates (83% - 99%),
                 while high soil moisture results in lower retention rates (32%
                 -90%). Soil moisture was, generally, low prior to storm 1 and
                 high prior to storm 2.       However, Big Slough. exhibited a
                 constant level of soil moisture due to flowing wells
                 throughout the subbasin.

            11.  A summary of physical water quality data for the watershed
                 stations is contained in Appendix C.      Maximum temperatures
                 occurred between May and September.      pH varied, generally,
                 from 6 to about 9, with lowest pH occurring during high
                 discharge (June - September), associated with high organic
                 acid content in the water.

            12.  Conductivity values ranged from 128 to 1090 umhos, with lowest
                 levels found during high discharge.

            13.  Dissolved oxygen values ranged from 0.05 to 15.40 ppm, with
                 roughly one-third falling below 5 ppm, and lowest values
                 generally found during July - September.

            14.  Dissolved organic carbon (DOC), NH,_ and PO   4 showed seasonal
                 variation. DOC had maximum concentrations during high runoff.
                 The other two parameters also exhibited highest concentrations
                 during high discharge but less consistently. NO,+NO2 did not
                 exhibit a similar pattern.

            15.  Total suspended solids (TSS) varied considerably, with highest
                 levels often occurring during high discharge.

            16.  Regression analyses indicated that only dissolved organic
                 carbon (DOC) concentrations were significantly related to
                 discharge at all stations.           Dissolved phosphate was
                 significantly related to discharge at six of eight stations.

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           17.  Dissolved organic carbon (DOC) was removed f rom the water
                column during estuarine transport f rom July through February.
                High particulate.concentrations of organic carbon in the head
                waters-of the estuary suggest that some of the DOC probably
                flocculates during this period.        In general, dissolved
                phosphate appears to follow the same pattern.

           18.  Dissolved NO +NO     and ammonia have complex estuarine
                distributions 3@Ut 2appear to be removed in the upper reaches of
                the estuary.   Higher levels occurred at higher salinities,
                suggesting the release of some soluble nitrogen.

           19.  Estuarine levels of total suspended solids (TSS) were high
                probably due to resuspension of estuarine sediment, upstreai
                transport from charlotte Harbor and/or biogenic particle
                production.

           20.  Sediment samples were collected form four (4) stations in the
                Myakka River and one (1) station in Charlotte Harbor.
                Concentrations of arsenic, cadmium, chromium, copper, lead
                nickel, zinc and mercury were compared with that of alumin:i
                to determine if these trace metals have been enriched over
                time.

           21.  Myakka River and Upper Charlotte Harbor sediments consisted
                largely of fine sands, which tend to have low metal
                concentrations.   Concentrations of all metals were low and
                fell within expected natural ranges.

           22.  Concentrations of TOC, TKN (total Kjeldahl nitrogen) and TP
                (total phosphorous) in Myakka River sediments were greatest in
                those   samples   which   also  had   the   highest    aluminum
                concentrations; high aliimiinum being an indicator of fine-
                grained sediments.

           23.  Sediment nutrient concentrations in the Myakka and Peace
                Rivers and Charlotte Harbor were compared to concentrations in
                natural sediments throughout Florida. TP/TKN ratios tended to
                be higher than typical values found throughout the state and
                are probably related to regional phosphate rock deposits.

           24.  Sediments were analyzed for organic compounds (i.e.,
                polynuclear aromatic hydrocarbons, chlorinated pesticides,
                polychlorinated biphenyls, and aliphatic hydrocarbons) . None
                were found in excess of detection limits.

           25.  Future technical reports will focus on more detailed trend and
                other analyses of data from both the basin and the estuary
                stations.





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           26.  The following management tools were developed, to varying
                degrees, as part of this study:              a one-dimensional
                hydrodynamic model; biological indicators (i.e., benthic and
                f loodplain vegetative communities) ; a shoreline assessment and
                mapping project, and; a spatially-related database.

           27.  As part of future work on this project, the above management
                tools will be further developed and a basin-wide management
                plan established to tie goals and implementation strategies.









































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                                     ACKNOWLEDGMENTS

                When a study like the Myakka River Basin Project is
           undertaken, many people offer contributions of time and expertise.
           We would like to recognize all the folks that have helped us
           through the first phase of the study.

                Thanks to the Environmental Chemistry Section of Mote Marine
           Laboratory, Kellie Dixon, Sue Hufman and Pat Minotti. They only
           asked a few times when the storm sampling events were going to be
           over, and they were always there when the samples arrived.

                Thanks to Fred Handy at Becky's Bait Bucket for his concern
           about the river and about the study. He was always there with an
           interesting story about the Myakka and to tell us what the salinity
           structure and tides would be like for our sampling runs.

                Thanks to Sarasota County's Steve Sauers, Dr. Jose Guira, and
           Laura Ammeson for helping us through some logistical problems early
           in the study.

                Thanks to the Tampa and Sarasota offices of the USGS for
           helping us locate, installing, and providing access to the
           continuous record gaging stations. Additional thanks for providing
           access to the hydrologic database, and answering questions.

                Mr. Chuck Downs and the Turners at the Hi Hat Ranch were most
           generous in providing access to the gaging stations and proposed
           sampling locations on their properties.

                A special thanks to Dr. Estevez of Mote Marine Laboratory for
           sharing his knowledge of the Myakka with us. Thanks, too, for that
           first excursion on the river in January, 1989.

                Finally, thanks to the staff of the. Ecological Monitoring
           Division for support and encouragement. Special thanks to Shari
           Knack for assisting in the production of this report, to Jamie,
           Jones and Mark Franz for assistance with the graphics, and to Dave
           Aftandilian for help with editing.













                                           xii












         I. Introduction

         Project Overview/Purpose
              Tn 1987, with funds made available through the National
         oceanic and Atmospheric Administration (NOAA), the Florida
         Department of Environmental Regulation's (FDER's) Coastal Zone
         Management (CZM) Section implemented an "Estuarine Initiative',
         aimed at improving research and management of Florida's estuaries.
         Projects were initiated in: Perdido Bay, on the'border of Florida
         and Alabama; Turkey Creek, in Southeast Florida; and the Little
         Manatee River, in the southern portion of Tampa Bay. In December
         1988, Sarasota County's Ecological Monitoring Division (EMD) and
         FDER's CZM Section initiated the fourth statewide project; an
         investigation of the Myakka River Watershed.

              The importance of proper management of the Myakka River Basin
         lies not only in the river's value as an Outstanding Florida Water
         and a Wild and Scenic River, but also because the Myakka River
         f lows into Charlotte Harbor, one of the largest and most productive
         estuaries in Florida. Projections for unprecedented growth in the
         region, and the concern over associated environmental impacts,
         focused additional attention on the need for a proper management
         program for the Myakka River Basin. Its size, accessibility and
         relatively undeveloped nature further made this basin a good
         candidate for the subject study.

              This study represents the first system-wide examination of the
         Myakka River Basin. Previous research within the-basin is limited
         to disjunct, non-synoptic studies. Although this information may
         have had localized regulatory value, it did not provide a
         defendable basis for: (1) projecting the cumulative impacts of
         changing land uses, nor; (2) developing desirable basin-wide
         management objectives or implementable strategies.

              The major objective of this three-year study was to provide a
         technical basis for holistic, basin-wide management for the Myakka
         River Basin. Accomplishing such a comprehensive objective requires
         effective tools that track land use changes, provide a mechanism
         for examining cumulative impacts, and link available data to
         planning and management decisions based on established goals for
         the system.   The best available management tool allowing such a
         holistic approach to management is the Geographic Information
         System (GIS).

              The first year (1989) focused on data collection and
         compilation.    Information was collected on the physical and
         chemical processes within the watershed, including rainfall,
         stream-flow,    water   chemistry   and   biological     communities.
         Additional work during the first year accurately characterized the
         river's shoreline and advanced the development of a predictive flow

                                           I








          model for the river. These data were necessary to properly develop
          management strategies for the basin.

               Accomplishments for year two included continued data
          collection and analyses, enhancement of the historical database,
          and the initial development of management strategies for the basin.
          Additionally, spatial coordinates were assigned to environmental
          data, allowing assimilation of these data into a GIS.

               The objective for phase three will be the development of a GIS
          for the Myakka River Basin.     The GIS will pro-@ide an important
          mechanism for timely assessment of impacts related to various
          development and management strategies. other work planned for year
          three includes: development of the management plan; establishment
          of goals for implementing the plan; and, integration of the GIS
          into the local government planning process.

          Research and Monitoring Program

               since the initial efforts by County staff to bring additional
          and proper management to the Myakka River Basin (Lincer, 1979),
          several research and monitoring efforts have been conducted as
          funds and political priorities allowed (Table A). Initial efforts
          included straightforward inventories which helped to identify more
          specific research needs.      These were followed by basin-wide
          studies, which will result in implementable management strategies.

          Description of the Report

               This report presents the results from the first year of the
          Myakka River Basin Project.      The emphasis for this report is
          analysis and documentation of data collected during the first phase
          of the project.     Subsequent reports will present results of
          continued   analyses   and   and  the   development   of    specific
          implementable management goals.

               The next section of the report describes the environmental
          setting of the Myakka River watershed, including subbasin
          descriptions, land use and habitat descriptions.       Section III
          describes the methods used for sample collection and analytical and
          statistical analyses. Results are discussed in Sections IV-VII
          The final section provides an assessment of the information ana
          provides the direction for subsequent reports.










                                           2








      TABLE A. overview of studies conducted within the Myakka River watershed.


            PHASE                                              SPECIFIC EFFORTS


           INITIAL          4     Myakka River Workshop
       INFORMATION                (Sarasota County, Myakka River Coalition, Ext. Service)
       GATEMZING/NEEDS
         ASSESSMENT


                                  Myakka Lake/VanderRipe Slough Study
                                  (Mote Marine Laboratory, Preide-Sedgwick)
       DATA GATHERING
          (Physical,              Wet & Dry Season Characterization; Downstream Studies, Phases I and
        Chemical and              (Mote Marine Laboratory)
         Biological)              Water Quality Work; Carlton Reserve Baseline Studies
                                  (Dames & Moore, Mote Marine Laboratory)

                                  Preliminary salinity Monitoring/Modelling
                                  (USGS)

                                  River Wetland Characterization; Downstream Studies, Phase III
                                  (Mote Marine Laboratory)

                            4     Myakka River Basin Project - Year 1; Water Quality, Flow and
                                  Freshwater Biology
                                  (NOAA/DER Grant to County*)

                                  Peer Review of Key Studies and Modelling Needs
                                  (NOAA)

                            4     Myakka River Basin Project - Year 2; Fine-Tuned Monitoring,
                                  Functions, Data Analyses pd GIS
                                  (NOAA/DER Grant to County

                            4     Stream Flow, Surficial Aquifer and Water Quality monitoring
                                  (USGS Cooperative Agreement with County, County Monitoring Program)




                                                                        3











       TABLE A (continued)


            PHASE                                           SPECIFIC EFFORTS

        ENVIRONMENTAL            Hydrological One-Dimensial Model; Downstream Studies, Phase IV
          MANAGEMENT             (Mote Marine Laboratory, Dr. Siler and USGS)

                                 County Involvement in Myakka River Management Plan and Rule-Makin
                                 (DNR)

                                 Development of County Environmental Database, Using Myakka River
                                 Prototype
                                 (Ecological Monitoring Division)

                                 Shoreline Habitat Computerized Drafting (CADD) Work
                                 (CADventure)

                                 Ecological Interpretation of Hydrological One-Dimensial Model;
                                 Studies, Phase V
                                 (Mote Marine Laboratory)
                            4    Nyakka River Basin Project - Year 3; Management Options/PC-GIS/Env
                                 Database
                                 (NOAA/DER Grant to County*)




                       Subject KOAA/FDER study being carried out by Sarasota County,'s Ecological M4











                                                                  4









         II. Environmental Setting of the Nyakka River Watershed

              The Myakka River is a meandering blackwater stream in South
         West Florida (Figure 1). The river drains approximately 1,559 km'
         and is the smallest of the three main tributaries of Charlotte
         Harbor (Hammett, 1989). The watershed includes portions of five
         counties (Manatee, Hardee, Sarasota, Desoto, and Charlotte). From
         Myakka Head in Manatee County to Cattle Dock Point (considered the
         river's mouth) in Charlotte County is a straight-line distance of
         50 miles. Measured in river miles, the distance increases by 40%
         to 70 miles.

              The Myakka River watershed lies directly in the path of future
         development in South West Florida. Currently the portion of the
         basin within Manatee County is used primarily for ranching and
         agriculture and is not intensively developed.          During 1990,
         phosphate mining was begun again in this part of the watershed.
         Within Sarasota County, much of the land along the Myakka River is
         in public ownership, including the Myakka River State Park, the T.
         Mabry Carlton Jr. Memorial Reserve, and the Walton Tract. Between
         the Walton Tract and US Highway 41 there are low density
         residential developments and some commercial water-related
         establishments. The portion of the basin south of Highway 41 is
         more intensively developed, with trailer parks and waterfront
         developments on both sides of the river.

              As the populations of Manatee, Sarasota, and Charlotte
         counties continue to grow, agricultural interests will be forced to
         move further east and into the watershed. Population growth will
         also push urban and suburban development further east as open space
         becomes more difficult to obtain.         These increasing growth
         pressures make it imperative that the drainage basin be managed as
         much as possible as an ecological and hydrological unit.


              General Physiography of the Watershed

              The terrain of the watershed is generally flat. Most of the
         basin lies within the coastal lowlands topographic region of
         Florida. A small portion of the headwaters of the basin (28.5 km@)
         is in the Central Highlands region (Joyner and Sutcliffe, 1976).
         Elevations in the basin range from 35 m at the headwaters to sea
         level at the river's mouth (Figure 2).      The slope in the upper
         reaches of the basin is approximately 1.5 m, decreasing to about
         0.3 m near the mouth (Drummond, 1977). Wetlands are a widespread
         and important component within the basin, particularly at
         elevations below 60 feet.    Research on the T. Mabry Carlton Jr.
         Memorial Reserve has shown that flatwoods wetlands reach a density
         of 70 kM2  (Winchester et al., 1985).   Four major depressions, or
         natural water detention areas, occur in the watershed. They are
         Flatford's Swamp, Tatum Sawgrass, Upper Lake and Lower Lake.


                                           5













                                      eye   86*    8V    840   830   820   BIG






                                                                                      -300








                                                                                0     -280









                                                                                        P.60

                              MANATEE             HARDEE
                               COUNTY             COUNTY

                                                                                      -250
                              BARACA
                               CO NTY
                                                 DE SOTO
                                                  COUNTY



                  MYAKKA RIVER           CHARLOTTE COUNTY
                   WIN AREA


          0         Is 20MILES
                 10

          0   10 20 30 KLIOMETRES






           FIGURE 1. Location of the 1(yakka River Basin (after Joyner and
                       Sutcliffe, 1976).























                      125-
                   J


                      100-
                   >            MYAKKA HAD
                   0
                   w
                   4


                   0
                   I'-                        RATFORD
                   4(   50-                    SWAMP
                   >
                                                           INTAKKA CITY              UPPER
                                                                                    MYAKKA
                        25-                                                          LAKE        towil
                                                                                                 LAKE




                          0                    10                                           30                    40                    so


                                                           DISTANCE. ALONG RIVER. FROM SOURCE. In miles






          FIGM 2. Elevational changes within the Myakka River Basin (from Drwmnond

                                                                                          7








                The major source of freshwater for the Myakka River is
          rainfall. The river is characterized by low base flow despite the
          fact that the water table can be as much as 10 to 15 feet higher
          than river water levels. Consequently, the Surficial Aquifer has
          a limited contribution to the river (Hammett, 1989).

                The Floridan Aquifer contributes.highly mineralized water to
          the river through Warm Mineral Springs and Little Salt Springs.
          These inputs occur downstream of river mile 12, in the estuarine
          portion of the river. The conductivity of the water from these
          springs    is   approximately   26.5   millimhos 'per      centimeter,
          corresponding roughly to salt water of 15 ppt salinity. Although
          Warm Mineral Springs contributes a constant flow of 0.28 cms to the
          river, the mineral content of the flow makes this a more brackish
          than a freshwater source (Rosenau et al., 1977).

                The study area has a humid, subtropical climate with long,,
          warm, moist summers and typically dry winters. The average yearly
          rainfall for the study area is 1423 mm. Most of this rain falls
          from June to September as a result of convective storms.            The
          rainfall amounts tend to vary widely across the study area because
          of the localized nature of convective storms. Frontal systems from
          the north occur in the winter months, and occasionally bring rain
          in February and March.      The area is subject to hurricanes and
          tropical depressions during the storm season (June through
          October). In September 1988, such a tropical disturbance dropped
          225 mm of rain in a three day period. This rainfall resulted in an
          8-fold increase in discharge for the Myakka River and a 50-year
          flood event.

                The hydrology of the Myakka River is strongly related to
          rainfall in the watershed.      Peak discharges occur from July to
          October. One station, with a period of record dating back to 1936
          has a mean discharge of 6.99 cms, with a range for discharge values
          between 0 and 245 cms. May has the lowest average discharge and
          September, the highest. Figure 3 illustrates the long-term trends
          for the USGS gaging station in Myakka River State Park (02298830).

                The soils along the Myakka River change from floodplain
          associated soils to salt marsh/mangrove-associated soils at river
          mile 15.5 (Soil Conservation service, 1988). In general, the soils
          in the watershed are sandy and poorly drained.

                Water quality in the Myakka River is considered "good"
          although mining, rangeland, and agricultural runoff contribute to
          elevated nutrient levels (Hand et al., 1988).           In the upper
          watershed, Wingate Creek and Clay Gully have "fair" water quality     -
          A section of the Myakka River between Ogleby and Owen Creeks has
          "poor" water quality due to elevated nutrients and bacteria counts.
          In the lower watershed, both Deer Prairie and Big Sloughs have
          "fair" water quality because of elevated bacteria and depressed
          dissolved oxygen levels.

                                            8







                                      Mean Monthly Disc harge
                                        MRBP Station #B 140

        80


        70


        60


        50
     E

        40 -


        30 -
     V

        20 -


        10 -
                               Al  A-
         0
          1937     1940     1943     1946     1949      1952     1955     1958     .1961



        80


        70 -


        60 -



     E
        50 -
     u
     %..0

     ID
        40 -


        30 -


        20 -


        10 -


         0
                                      97
          1964     1967     1970     1  3     1976     1979      1982     1985     19 88


        FIGURE 3. Long-term discharge at the USGS gage at Hyakka River
                    State Park (B140).

                                              9










                Subbasin Descriptions

                The Myakka River basin is composed of over 60 subbasins
           (Figure 4).     However, not all the individual subbasins are
           associated with a continuous record gaging station. Therefore, for
           the purposes of this study, the watershed was divided into eight
           gaged subbasins. Each gaged subbasin contains a number of minor
           ungaged basins.     Table B names the subbasins and lists the
           associated minor drainage basins.

                The Myakka Head subbasin is located in eastern Manatee County
           and western Hardee County and drains approximately 323.75 km         2.
           This area contains many small creeks that flow into the first of
           four major water detention areas associated with the river,
           Flatford's Swamp. The swamp covers an area of about 15.5 km-
           northwest of Myakka City.

                The primary land use in this subbasin is agriculture.           A
           phosphate mine reopened in July 1990 in this subbasin in the
           northern portion of the basin along Johnson Creek.

                The Myakka River is a small meandering creek in this subbasin.
           During much of the year, it is hardly a meter wide at the State
           Road 64 bridge. The channel is fairly well defined above and below
           Flatford's Swamp, but becomes poorly defined as the swamp widens to
           cover a large area.    The river is channelized just north of the
           gaging station at Myakka City.      The average discharge at this
           station is 3.7 cms, with a range from 0 to 191 cms. Myakka City
           and State Road 70 delineate the downstream extent of this subbasin.

                Downstream of Myakka City, the river flows southwest through
           southeastern Manatee County and the Tatum Sawgrass subbasin. The
           103.6 kM2 drainage area also includes portions of western Sarasota
           County.  This subbasin also contains the second major detention
           area in the watershed, Tatum Sawgrass.

                Agricultural land use is also dominant in this          subbasin.
           Although it is not heavily developed, the subbasin has been altered
           for agricultural development. Prior to 1974, Tatum Sawgrass was a
           large (36.26 kM2) freshwater wetland. Private interests installed
           dikes and ditches in this wetland to allow agricultural
           development. The alterations also reduced the storage capacity of
           this area and increased the magnitude and frequency of flood events
           downstream. The largest change in flood stage was a 19% increase
           in the 2-year flood (Hammett et al., 1978).







                                            10





                                  A 19   a 23                  A 20    a 2f                  a 21   R 22                 A 22 A 23                           1Biio





                     1 34
                                                                                                                                           T 34
                     IL-35                                                                                                                                   B130
                                                                                                                                                         1H

                                                                                                                                                             B140


                                                                                                                                           T 3 .5

                                                                                                                                               36

                                                                                                                                                             B150





                                                                                                                                           T                 B17 0
                                                                                                                                               36
                     737
                                                                                                                                           T   37    1>
                                           T T   I IL 11                                                                                                     >
                                                                                                                                                         1>
                                                                                                                                                        1>
                                                       Mr.            m
                                                                       Lh

                                                                                                                                                             B120
                                                                                                 444


                     T 37                                   1 1 K. 1
                                                                                                                                           7 37
                     t 38
                                                                                                                                               is
                                                                             p                                                                               B160
                                                                       1>

                                                                t>
                     IT 38                                                                                                                                   B180
                     ri a                                                                                                                  1 39

                                                                                                                                                          Gaging
                                 f                                                                                                                   *4440*0::::
                                          7r                                    77                                                                      Station
                     T 3
                                                                                                                                           T 39
                     T 40                                                                                                                  ---1
                                                                                                                                           T40






                                                                                       -!b

                     T 40                                                                                                                  T 40

                     t 41                                                                                                                  T 41



                                R Iola 2;                   a 201A 21                     q 21  A 22                   A 22  P 23
                     I@t'j














               FIGURE 4. Subbasin and gaging station locations within the Hyakka
                                       River Basin.










               TABLE B.       Basin names and associated drainage areas.

                  Sampling
                  Station Major Basin               Minor Basin(s)

                    B I 10 Myakka Head              Johnson Creek
                                                    Wingate Creek
                                                    Coker Creek
                                                    Taylor Creek
                                                    Sand Slough
                                                    Young Creek
                                                    Long Creek
                                                    Boggy Creek
                                                    Ogleby Creek
                                                    Maple Creek
                                                    Owen Branch
                                                    Sand Branch
                                                    Owen Creek
                                                    Three (3) unnamed drainage areas

                    B120 Howard Creek               Howard Creek

                    B130 Tatum Sawgrass             Tatum Sawgrass Slough
                                                    Sardis Branch
                                                    One (1) unnamed drainage area

                    B140 Upper Lake                 Indian Creek
                                                    Clay Gully
                                                    Mossy Island Slough
                                                    Howard Creek
                                                    One (1) unnamed drainage area

                    B ISO Ut)per Big Slough         Bud Slough
                                                    Wildcat Slough

                    B160 Lower Lake                 Fish Camp Drain

                    B170 Deer Prairie Creek         Deer Pairie Slough

                    B180 Lower Big Slough           Mud Lake Slough
                                                    Big Slough



                      Approximately 2 kilometers east of the Manatee/ Sarasota County
               line, the Myakka splits into the main channel, which heads west and
               skirts the southern edge of Tatum Sawgrass, and Clay Gully, which
               goes south and enters Upper Myakka Lake at its northeast corner.
               Due to alterations in Tatum Sawgrass, most of the normal flow of
               the river flows through Clay Gully, which has been dredged. The
               main channel of the river flows only during periods of high flow

                                                              12









          (Bowman, pers. comm.).     The gaging station for this subbasin is
          located on the State Road 780 bridge, and gages the flow of the
          main channel. The gage, which was installed for this study, showed
          a range of discharge from 0 to 103.6 cms during 1989.

               Immediately downstream of the 780 bridge, the Myakka River
          enters Upper Myakka Lake and the Myakka River State Park.            The
          drainage area associated with the Upper Lake subbasin is 114 km2
          and includes parts of northeastern Sarasota County and the northern
          portion of the State Park. Upper Myakka Lake, the third of the
          detention areas in the watershed, is located within this subbasin.

               Much of the Upper Lake subbasin is publicly owned.         To the
          north and west of Upper Lake are residential areas (zoned for low
          density, 1 unit per 5 acres).            These areas also include
          agricultural lands used for plant nurseries, range land, and citrus
          production.

               Upper Myakka Lake is a shallow depression.          The water is
          nutrient -enriched and the lake exhibits seasonally low dissolved
          oxygen levels and aquatic weed problems. Agricultural activities,
          spray irrigation fields and an effluent treatment system along
          Howard Creek are possible contributors to the poor water quality of
          the lake. Historically, Upper Lake had two outfalls, the Myakka
          River and Vanderipe Slough. The outfall to Vanderipe Slough was
          blocked with an earthen dam in the 1930's, and water no longer
          exits the lake there. Also in the 1930's, a dam was constructed at
          the outfall of the Myakka River in an attempt to better regulate
          water levels downstream. Culverts were later built to bypass this
          dam. Between the main channel of the Myakka and Vanderipe Slough
          is a large area of wetlands which are generally inundated during
          periods of high flow.

               The gaging station for this subbasin is on the main channel of
          the river, approximately 0.8 kilometers upriver from State Road 72.
          The mean discharge for the period of record at this site is 6.99
          cms, and the range is from 0 to 245.5 cms.

               Moving downstream, the Myakka becomes more a river and less a
          stream. At State Road 72, the channel is 50 meters wide and three
          meters deep at the center. As the river winds south through the
          marshes toward Lower Myakka Lake, the oak-cabbage palm hammock
          opens to a wide fresh water wetland that extends to Lower Myakka
          Lake.   The Lower Lake subbasin drains 62 km2 of central Sarasota
          County and the wilderness area of the State Park.

               Lower Lake is the fourth major detention area in the Myakka
          River watershed. Like Upper Lake, it is generally a shallow lake
          with an abundance of aquatic weeds. It does have one feature that
          sets it apart from Upper Lake, Deep Hole.           Believed to be a
          collapsed sinkhole, Deep Hole is 91.5 meters in diameter and 45 to


                                            13









           55 meters deep. Joyner and Sutcliffe (1976) reported a groundwater
           discharge of 0.04 cms. A video camera survey by the Mote Marine
           Laboratory in 1978 revealed an inverted cone of sediment nearly 24
           meters tall, suggesting a sediment sink rather than a ground water
           source.


                The Myakka River continues its meandering course generally
           south from Lower Lake. A private landowner built a dam just south
           of the State Park boundary (river mile 28.6).         The dam is a
           concrete structure with a 1.2 m  2 gate which is.generally closed
           The dam holds back about 1.2 meters of water, though high seasonai
           flows frequently overtop the dam.     The gaging station for this
           subbasin has an average discharge of 9.6 cms with median discharge
           of 2.9 cms.


                The four subbasins described above are on the main river
           channel. The remaining four basin gaging stations are located on
           tributaries of the Myakka: Howard Creek, Deer Prairie Slough, and
           Big Slough (two stations) .    Howard Creek discharges into Upper
           Myakka Lake.   Both Deer Prairie Slough and Big Slough enter the
           estuarine portion of the Myakka River at river miles 12.2 and 9.4,
           respectively.

                Howard Creek drains 51.8 km@ in northeastern Sarasota County.
           The creek flows south and enters the northwest portion of Upper
           Myakka Lake. The subbasin includes diversified agriculture,
           including cattle, citrus and sod operations. In April 1990, the
           City of Sarasota rerouted treatment plant effluent from Sarasota
           Bay to a ridge and furrow disposal system in this subbasin. The
           ridge and furrow system is designed for zero off-site discharge and
           to withstand a 5-year storm event. During the 1990 rainy season,
           the system's capacity was exceeded, and the effluent was again
           routed into Sarasota Bay. The range of discharge recorded at this
           gage is from 0 to 62.8 cms.

                Deer Prairie creek drains an area of 86 km2 in central
           Sarasota County. The creek is the major water conveyance for the
           T. Mabry Carlton Jr. Memorial Reserve, a 129.5 kM2  parcel owned by
           Sarasota County. It also drains the eastern portion of the Myakka
           River State Park.    Agriculture is the major land use in this
           subbasin.   An earthen dam impounds the creek 3.2 kilometers
           downstream from the gaging station.    The dam was constructed to
           prohibit brackish water from moving any further upstream, allowing
           year-round agricultural use of the water. The average discharge at
           this station is 0.72 cms and ranges from 0 to 27.5 cms.

                The Big Slough (also known as Myakkahatchee Creek) basin has
           two gaging stations associated with it.     The gaging station at
           State Road 72 represents a drainage area of 94.5 km 2. The primary
           land use in this   2part of the subbasin is agriculture.           An
           additional 130.3 km is gaged at Interstate Highway 75. Big Slough


                                           14









          was been dredged to provide more efficient transport of water to
          the City of North Port in southern Sarasota County. The city uses
          this creek as its major source of drinking water.          The gaging
          station on upper Big Slough has a period of record of 8 years. The
          mean discharge for the period was 0.9 cms, ranging from 0 to 70.2
          cms. The downstream gage, installed specifically for this study,
          showed discharges ranging from 0.01 to 6.09 cms.


          soil and vegetation Types in the Watershed

               In the Myakka Head subbasin,, the vegetation near-the river and
          @hroughout Flatford's Swamp is hardwood hammock. This association
          includes a canopy of ash (Fraxinus caroliniana), swamp maple (Acer
          rubrum) , bay (Gordonia larianthus) , hickory (Carya acruatica) , water
          oak (Quercus nigra) and magnolia (Magnolia grandiflora) .           The
          understory includes many vines, ferns, and an occasional saw
          palmetto (Sereno repens) thicket (Morris and Miller, 1976).

               The vegetation along the river changes from the hardwood
          hammocks of the Myakka Head subbasin to oak and cabbage palm
          hammock in the Tatum Sawgrass, Upper and Lower Lake subbasins. The
          canopy in this type of hammock is comprised of laurel (Quercus
          laurifolia) and live oaks (Ouercus virginiana) and cabbage palms
          (Sabal palmetto). The understory includes saw palmetto and various
          shrubs and grasses (Morris and Miller, 1976).         Some freshwater
          wetlands-associated plants including St. John's wort (Hypericum
          fasiculatum), pickrelweed (Pontaderia sp.), arrowhead (Sagittaria
          lancifolia) and beakrush (Rhynchospora sp.) remain in the deeper
          depressions, around the lakes and along sloughs.

               Near river mile 15, in the estuarine reach of the river, the
          oak and cabbage palm hammocks give way to the salt marsh/mangrove
          plant associations. Cord grass (Spartina sp.), black rush (Juncus
          roemerianus) , leather fern (Acrostichum aureum) , and cattail (Typha
          sp.) dominate the tidal marshes, along with red (Rhizophora
          mangle), black (Avicennia Serminans), and white mangroves
          (Languncularia racemosa) (Estevez, 1985).

               Pine flatwoods, composed of a canopy of slash pine (Pinus
          ellioti) and an understory of saw palmetto, dominate the remainder
          of the basin. Other vegetation types present in the basin include
          prairies and improved pasture.

               In the upper reaches of the watershed, the soils near the
          river are typically alluvial, sandy, with low organic content. At
          river mile 15.5, the organic content of the soils increases,
          marking the transition from fresh to saltwater habitats (Soil
          Conservation Service, 1988).

               The soils in the remainder of the basin are typically soils of
          the flatwoods. These soils are level and sandy. Most are poorly

                                            15








           drained and have a subsoil that is dark colored and sandy in the
           upper part and loamy in the lower part (Soil Conservation Service,
           1988).



                Description of the Estuarine Study Area

                The study area for the estuarine reach of the Myakka River
           extends from river mile 21 to river mile -2 in Charlotte Harbor.
           The tidal reach is normally well mixed, with stratification
           occurring in the downstream portion of the river        ' only during
           periods of high flow and high tide. Backwater effects from tides
           have been recorded as far upstream as river mile 28.6 (the control
           structure in the Lower Lake subbasin) during periods of low flow.
           At river mile 26.1, the daily fluctuation in stage averaged 0.13
           meters due to tidal effects (Hammett, 1989).       There are 4 major
           tributaries in the estuarine reach of the river (Figure 5). They
           are: Curry Creek, Deer Prairie Creek, Warm Mineral Springs, and Big
           Slough.

                 Downstream of the control structure, the river channel is
           deeply incised, and the limestone bed of the river is frequently
           exposed. The river continues to meander through oak-cabbage palm
           hammock on a south-southwest course through central Sarasota
           County.    Numerous narrow, shallow sloughs, most of which are
           abandoned meander loops of the river, characterize the river area
           from the control structure to river mile 23.5 (Milligan, 1990).
           Pine flatwoods extend to the banks of the river in several areas
           along this segment of the river. Where the river flows through
           these relatively higher and drier sections, high sand bluffs have
           been created. The water in this river segment is generally fresh.

                Between river miles 23.5 and 22, the character of the river is
           very similar to the segment upstream. The sloughs, however, become
           .less numerous, wider and deeper.     These sloughs are lined with
           willow (Salix caroliniana) and popash, and frequently contain
           floating mats of marsh vegetation (Milligan, 1990).         The f irst
           residential development on the river occurs at river mile 23 on the
           west bank of the river. Residences occur on the west bank of the
           river to river mile 21 (Border Road).

                From river miles 22 to 16,, the river begins to change.
           Sloughs become nearly absent from the landscape. The river becomes
           less meanderous and the channel less incised. The laurel and live
           oaks in hammocks are replaced by pines. Residential developments
           occur on both sides of the river from river miles 21 to 19.5
           (Interstate 75) .   The influence of Charlotte Harbor's tides is
           evidenced by elevated salinity during periods of low flow.           In
           1985, salinity at Border Road exceeded 10 ppt (Hammett, 1989). A
           salinity of 2 ppt was recorded at river mile 19.5 by project staff.


                                             16








                                                   a 19 A 2z,                 R 20 A 21                     R 21 A 22                   R 22 R 23







                                     T
                                     1 3@                                                                                                                  T 34
                                                                                                                                                           T 35









                                     T 35
                                                                                                                                                           T 35
                                     T 36
                                                                                                                                                           T 36







                                  -IT 36
                                     T 37                                                                                                                  T 36
                                                                                                                                                           T 37





                                     :T 37                                                                                                                 T 37
                                     T
                                        39
                                                                                                                       d                                   T 38





                                                                               b
                                                             Ool@
                                     !_T 31 - -/I'.       , -
                                                                                                                                                           T 38
                                     T 39        a
                                                                                                                                                           T 39





                                                                                    c
                                                                                                                                         71


                                     T 33


                                     T 4
                                                                                                                                                           T 39


                                                                                                                                                           T41,









                                     T 40                                                                                                                  T
                                                                                                                                                              @O
                                     :T 41                                                                                                                 T 411
                                                 A 491A                      A 20 R 21                    A 21 R 22
                                     1                                            1                            1                       R 22  R 23

                FIGURE 5. Major tributaries of the Myakka River estuary; (a) Curry
                                          Creek; (b) Deer Prairie Creek; (c) Warm mineral springs;
                                          (d) Big Slough.                                      17








               The most upstream of the four major tributaries, Curry Creek%
               occurs at river mile 20.2.                   Table C lists the estuary sampling
               sites and associated salinity data collected during 1989. Snook
               Haven Fish Camp and a campground are located at river mile 17.8.



               TABLE C. Salinity values for estuarine stations.

                                                                -salinity
                      Site        River Mile          Mean, ppt           Range, pp@t

                      E280            16.5                1.50              0.0-11.0
                      E270            14.2                3.26              0.0-15.1
                      E260            12.2                5.57              0.1-18.1
                      E250            10.6                8.23              0.2-20.1
                      E240             8.5              10.05               1.0-21.5
                      E230             5.o              15.56               5.2-24.9
                      E220             3.0              18-84               9.5-26.1
                      E210            -2.0              23.37              17.4-27.9




                      Below river mile 15, the                    river widens and the fringing
               hammocks give way to salt marshes dominated by black rush and
               leather fern. The river remains undeveloped between Snook Haven
               and river mile 11.5, with the exception of a campground at river
               mile 14.5. The first mangrove along the river occurs near river
               mile 13. Deer Prairie Creek enters the Myakka at river mile 12.2,
               just upstream of the Highway 41 bridge.

                         Residential development increases below river mile 11.5
               (Highway 41 bridge). Many of the developments include canals for
               river access, extensive use of hardened shorelines and numerous
               piers and docks.            Approximately 18% of the shorelines from this
               point to the mouth of the river have been hardened. The disturbed
               nature of this river segment is also reflected by the presence of
               two      exotic        plant         species,         Brazilian          pepper         (Schinus
               terebinthifolius) and Australian pine (Casuarina eqgisetifolia),
               along 27% of the shoreline (Estevez et al., 1990).

                      The hogchocker (Trinectes maculatus) has been identified as
               the dominant f ish species in the tidal Myakka River (Estevez, 1985;
               1986).      This fish accounted for 81% of the total number of fish


                 Curry Creek canal was dredged in the late 1950's to provide an outlet for approximately 10% of
               the seasonal flood flows of the Myakka River. The canal is approximately 5 miles long, connecting
               the river with Roberts Bay on the west coast. The original engineering plans for the canal indicated
               that excess flow would be directed toward the west and Roberts Bay (De Leuw, Cather, and Brill,
               1959). Recent empirical evidence, however, indicates that the canal does not function as intended.


                                                                18









         collected in trawls during 1985 studies.         The hogchocker is
         primarily a demersal f eeder, indicating that the benthic infauna
         and epifauna are the major energy pathway in this portion of the
         river (Browder, 1987).

              Studies of the benthos by Mote Marine Laboratory (Estevez,
         1985; 1986; Milligan, 1990) suggest various zonation schemes for
         the river based on this important component. The zones differed
         for molluscs, annelids, and crustaceans.     The suggested schemes
         might be better judged based on the additional studies of the food
         habits of the hogchocker in-situ (i.e. anaiysis of stomach
         contents).   The schemes also need to be related to zonations
         suggested by soil types, vegetation associations, and salinity
         distributions.

              The lower portion of the Myakka River, beginning at river mile
         2, is protected as part of the Charlotte Harbor Aquatic Preserve.
         The Peace River flows into Charlotte Harbor south of Hog Island at
         river mile -2. The Peace River exerts a strong influence in the
         salinity structure in the lower part of the Myakka River.































                                          19













         III. STUDY METHODS

         Rainfall and Hydrology

              Rainfall

              Rainfall measurements are taken at several stations within the
         study area; however, these stations are not distributed evenly
         across the watershed.     Therefore, rainfall data could not be
         obtained for each "delineated" subbasin.       Figure 6 shows the
         locations of the rainfall stations within and ndar the watershed.
         Rainfall data used in this report were collected by MOAA, Sarasota
         County, Florida Department of Natural Resources (FDNR; Myakka River
         State Park), and the North Port Water Authority.

              NOAA maintains a climatological observation network for the
         entire United States. Three of these stations were used to assess
         long-term rainfall patterns for the study area. The station at the
         Myakka River State Park is the only one of the three located within
         the watershed. The station at Fort Green lies just north of the
         northeast corner of the watershed. The Venice station lies west of
         the basin. Table D gives the coordinates and periods of record for
         these stations. Several rainfall stations, maintained by the Park
         Service, Sarasota County, and the North Port Water Authority, occur
         within the watershed.    The period of record for these stations
         ranges from five to six years (Table E).

              Total rainfall and monthly means were calculated for each
         long-term rainfall station to determine how rain during the study
         period related to long-term patterns.        This information was
         important for providing perspective on whether rainfall patterns
         and amounts found during the course of the study were reflective of
         average or "normal" conditions.

              The short and intermediate-term rainfall records provide
         information on the spatial variation of rainfall that can exist
         within the study area. Spatial differences in rainfall related to
         summer convective storms were examined by comparing monthly
         rainfall totals for June 1989 through September 1989 for six
         stations within the river basin.

              Hydrology

              As part of a cooperative agreement with Sarasota County, the
         United States Geological Survey records stage and discharge at
         several sites within the Myakka River basin. Four gaging stations
         are located on the main body of the River, one on Howard Creek, one
         on Deer Prairie Slough, and two on Big Slough Canal (Figure 4).
         Table F lists the gaging stations that were coupled with sampling
         locations for this study and the period of record for each. one
         record includes values since 1936, although most of the records


                                         20






                                                                                                                                                              A A
                                                                        A 19  R 25               A 20  A as                 A 21  A 22                R 221A 23


                                                          f_1_34
                                                                                                                                                                         T 34

                                                                                                                                                                         T 35








                                                           T 35
                                                                                                                                                                         T

                                                                                                                                                                         36









                                                                                                                                                                         T 36

                                                                                                                                                                         T 37



                                                                                         02
                                                         J 37                            0 M93,
                                                                                                            j    3                                                       T 37
                                                                                                                               4

                                                                                                                                                                         T 38
                                                                                                                    MS1

                                                                                              MS2
                                                                            _@pS4
                                                                                                                                                                         T
                                                                                                               '_=r'L7                                                   1 39
                                                                                                                    r--j
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                                                            33
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                                                                                                                                                                         T 3-1

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                                                                                                                                                                         T 40

                                                         T 41
                                                                                                                                                                         T 41



                                                                    a :9@4                   A 20IR at                  A at R 22                 a 22  A 23


                            FIGURE 6.                  Location of rainfall stations vithin and near the Hyakka,
                                                       River vatershed. Long-term stations are: (a) Fort Green;
                                                       (b) Hyakka River State Park; and (c) Venice. Short-term
                                                       stations at Hyakka River State Park are: (1) Morth
                                                       Entrance; (2) FPL; (3) Rookery; and (4) Preserve.
                                                       Stations MS1-MS5 are on the Carlton Reserve.


                                                                                                            21













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       TABLE F. Summary of information on USGS gaging stations within the MYakka River watershed.
         Station   Gaging    Location                                                           Average
           ID     Station    Lat/Long             Name                Period of Record      Discharg


         -BIIO    02298608    27-2036       Myakka River at         Feb 1963 - Sept 1966;          3.7
                              820925          Myakka City            Oct 1977 - present


          B120    02298760    271717         Howard Creek            Oct 1983 - present            N/A
                              822025         Near Sarasota



          B130    02298700    271805        Myakka River at          Apr 1989 - present            N/A
                              82-1515       S.R. 780 bridge


          B140    02298830    271425          Myakka River           Aug 1936 - present            6.99

                              821850         Near Sarasota



          B150    02299410    271135        Big Slough Canal         Oct 1980 - present            32.5
                              820840        Near Myakka City


          B160    02298880    271107           akka River at         Mar 1986 - present            9.6

                              822121      Control Near Laurel



          B170    02299160    270651      Deer Prairie Slough        Apr 1981 - present            0.72

                              821550   Near North Port Charlotte



         -B180    02299455    270630        Big Slough Canal         Apr 1989 - present            N/A
                              821220          in North Port


                                                                      23










          have a much shorter period of record. Two gages (at stations B130
          and B180) were installed in 1989, specifically for this project.

               As with rainfall, the long-term discharge records allowed
          comparisons of data collected in 1989 with mean values established
          over the entire period of record.        A composite hydrograph of
          discharge for the entire period of record was developed for each
          gaging station. These data were then compared to discharge data
          for the project year. This comparison was used to determine if the
          period of intensive study was representative of "normal" hydrologic
          conditions for the river.


          Storm Hydrographs and Rainfall


               A detailed analysis of rainfall/runoff relationships within
          the Myakka River basin was carried out by developing storm
          hydrographs for the eight gaging stations located along the major
          tributaries of the watershed.      The discharge data used in the
          development of the hydrographs is summarized in Table G.

               Two periods of rainfall activity in the 1989 study year were
          chosen to represent typical storm conditions within the basin.
          Rainfall data from eleven regional monitoring stations were used in
          the development of the hydrographs. These data are summarized in
          Table H.    Rainfall and streamflow data collected during these
          periods was used to develop the storm hydrographs.         The f irst
          periodf hereafter referred to as storm 1, began on July 15 and
          continued until August 9.     Frequent convective storms occurred
          during this period producing substantial variations in distribution
          of rainfall throughout the watershed. The second period, storm 2,
          began on September 22 and continued until October 16.        Rainfall
          during this period occurred within a four day span which was
          preceded and followed by periods of inactivity.

               The storm hydrographs for both periods were developed by the
          methods detailed below.       However, because of the distinct
          differences in rainfall patterns between the two periods, the
          methods used to analyze the hydrographs differed for each storm
          event. The results of the hydrograph analyses appear in Tables I
          and J.



               Hydrograph Development

               Two hydrographs, corresponding to the two storm periods, were
          developed for each of the eight stream gaging stations and
          corresponding subbasins. These hydrographs were constructed in a
          manner that would facilitate the use of United States Soil
          Conservation Service (SCS) methods of analysis. Discharge data for


                                           24






            TABLE G. sunmary of monthly discharge (cms) data at six USGS gaging static
                              River watershed.


                Stream Gauge                        i         F        M        A        M                          A        S        0


                Myakka City (2298608)
                    Total    Monthly              26.32    '12.96   60.87     13.65    12.31   48."     369."    263.16   232.97   78.39     17.
                    Mean    Daily                 0.85      0.46     1.96     0.46     0.40     1.63     11-94    8.49     7.75    25.30     0.
                    Median - Daily                0.40      0.40     0.71     0.37     0.09     0.48     8.66   - 9.28     6.59     1.47     0.
                    Maximum - Daily               2.80      1.02     9.71     1.90     3.03     8.60     27.25    12.82   21.65    12.03     0.
                    Minimum - Daily               0.28      0.31     0.28     0.14     0.02     0.02     4.95     3.11     1.42     0.68     0.

                Howard Creak (2299760)
                    Total    Monthly              1.86      0.83     1.01     O.OD     O.OD     O.W      0.22     7.53    31.83     4.12     0.
                    Mom     Daily                 0.06      0.03     0.03     0.00     0.00     0.00     0.01     0.24     1.06     0.13     0.
                    Median - Daily                0.02      0.02     0.02     0.00     0.00     0.00     0.00     0.45     1.06     0.09     0.
                    Maximum - Daily               0.24      0.05     0.10     0.00     O.W      O.W      0.06     0.68     2.55     0.76     0.
                    Minimum - Daily               0.02      0.02,    0.00     0.00     0.00     0.00     0.00     0.10     0.14     0.03     0.
                Nyakka/Sarazota (229800)
                    Total - Monthly               61.07    50.29    71.91    39.90     32.18    15.77   =.21     238.03   271.74   215.42
                    Mean - Deny                   1.97      1.80     2.32     1.33     1.04     0.53     8.14     7.68     9.06     6.95     1.
                    Median - DaUY                 1.56      1.73     3.11     1.95     1.53     0.57     9.86     9.17    10.92     5.55     1.
                    Maximum - Daily               2.69      2.69     3.40     1.67     -1.27    1.67     15.31    11.18   14.91    16.50     2.
                    minimum - Daily               1."       0.99     0.96     1.08     0.57     0.24     1.92     5.38     4.90     2.41     1.

                Hyakka/Laurel (ZMM)
                    Total    Monthly              1.73      1.62     2.07     0.00     1.40     1.29     5.22     5.56     5.84    249.78    30.
                    Mean    Daily                 0.06      0.06     0.07     0.00     0.05     0.04     0.17     0.18     0.19     8.06     1.
                    Median - Daily                0.05      0.06     0.07     0.05     0.04     0.04     0.18     0.18     0.20     8.38     1 .
                    maximum - Daily               0.07      0.07     0.08     0.00     0.06     0.05     0.23     0.22     0.25    24.59     2.
                    "404     - Daily              0.04      0.05     0.05     O.OD     0.04     0.04     0.05     0.15     0.14     2-.63    0.

                Dear Prairie Slough   (2299160)
                    Total    Monthly              0.99      0.48     0.87     0.00     0.00     0.04     2.12     20.04   17.50     6.74     1.
                    Mom     Daily                 .0.03     0.02     0.03     0.00     0.00     0.00     0.07     0.65     0.58     Oo22     .0.
                    Median - Daily                0.02      0.02     O.M      0.00     0.00     0.00     N/A      1.08     0.93     0.18     0.
                    Maximum - Daily               0.13      0.04     0.08     0.00     0.00     0.01     0.71     2.09     2.07     0.62     0.
                    Minimum - Daily               0.01      0.01     0.00     0.00     0.00     0.00     0.00     0.13     0.10     0.10     0.

                Big Slough Conal (2299410)
                    Total - Monthly               3.15      3.81     6.11     2.87     2.30     2.40     16.24    20.50   12.27     9.03     2.
                    Mean - Daily                  0.17      0.14     0.20     0.10     0.08     0.08     0.52     0.66     0.41     0.29     0.
                    Median     Daily              0.12      0.13     0.17     0.10     0.07     0.08     0.45     0.57     0.28     0.19     0.
                    Maximum     Daily             0.48      0.17     0.62     0.16     0.27     0.17     1. 16    2.52     1.50     1.30     0.
                    Minimum - Daily               0.09      0.10     0.07     0.06     0.05     0.04     .0.12    0.15     0.13     0.08     0.

                                                                                           25








                 TABix H. (continued)





                 Rain Gouge                   3          F          M           A          M           j          i           A          S


                 Preserve
                    Total Rainfall        59.94        1.78      98.55       22.61       39.88    213.61      246.89     106.17      207.01      106.
                    Mean - Daily           2.03        0.00       3.30        0.76       1.27        7.11       7.87       3.56        6.86       3.
                    Median - Daily         0.00        0.00       0.00        0.00       0.00        1.52       1.52       0.00        0.76       0.

                 HOAA
                    Total Rainfall        71.88        5.84      41.15        18.54      32.00    194.82      244.09     140.46      178.56      75.
                    Mean - Daily           2.29        0.25       1.27        0.51       1.02        6.60       7.87       4.57        5.84       2.
                    Medain - Daily         0.00        0.00       0.00        0.00       0.00        5.59       0.00       0.00        1.27       0.

                 -MS2
                    Total Rainfall        79.50        8.89      87.88        5.08       3.56     208.03      112.27     130.56      108.20      61.
                    Mean - Daily           2.54        0.25       2.79        0.25       0.00        6.86       3.56       4.32        3.56       2.
                    Median - Daily         0.00        0.00       0.00        0.00       0.00        0.00       0.00       0.00        0.00       0.

                 MS3
                    Total Rainfall        57.15        2.54      74.17        6.10       38.35    130.56      107.95       60.45     205.23      92.
                    Mean - Daily           1.78        0.00       2.29        0.25       1.27        4.32       3.56       2.03        6.80       3.
                    Median - Daily         0.00        0.00       0.00        0.00       0.00        0.00       0.00       0.00        0.25       0.

                 MS4
                    Total Rainfall        51.05        3.56      11.94        6.60       5.59     177.80      274.83     185.17      235.46      63.
                    Mean - Daily           1.52        0.25       0.51        0.25       0.25        5.84       8.89       6.10        7.87       2.
                    Median - Daily         0.00        0.00       0.00        0.00       0.00        0.00       0.00       0.00        0.51       0.











                                                                                                  27




    M M4 M, M) M, MI M mi M, M) Mj Mf M, M) M




          TABI,E H. Sunmary of monthly rainfall (mm) data within the Hyakka River wate




            Rain Gauge                            F          M          A          M          i           i          A          s          0


            Ft. Green
              Total Rainfall        68.58       0.00      46.99      29.21        3.81    298.45     261.11      176.53     168.91      25.40
              Mean - Daily           2.29       0.00       1.52       9.65        0.25       9.91       8.38       5.59       5.59       8.13
              Median - Daily         0.00       0.00       0.00       0.00        0.00       2.54       0.00       0.00       0.00       0.00

            Myakka River State Park
              Total Rainfall        71.88       5.84      25.91      18.54       32.00    195.07     244.09      139.70     175.01      100.58
              Mean - Daily           2.29       0.25       0.76       0.51        1.02       6.60       7.87       4.57       5.84       3.30
              Median - Daily         0.00       0.00       0.00       0.00        0.00       2.29       0.00       0.00       11.43      0.00

            Venice
              Total Rainfall        69.85       3.81      67.31      14.99        1.52    215.90     138.18      140.46     223.01      47.24
              Mean - Daily           2.29       0.25       2.29       0.51        0.00       7.11       4.57       4.57       7.37       1.52
              Median - Daily         0.00       0.00       0.00       0.00        0.00       0.00       0.00       0.00       1.78       0.00

            North Entrance
              Total Rainfall        79.25       5.08      83.57      16.26        3.56    213.61     236.98      165.35     188.72      53.85
              Mean - Daily           2.54       0.25       2.79       0.51        0.00       7.11       7.62       5.33       6.35       1.78
              Median - Daily         0.00       0.00       0.00       0.00        0.00       2.03       3.81       0.00       1.27       0.00

            FPL
              Total Rainfall        64.01       10.41     71.63      34.80        6.86    270.76     119.38      152.40     219.96      69.34
              Mean - Daily           2.03       0.51       2.29       1.27        0.25       9.14       3.81       4.83       7.37       2.29
              Median - Daily         0.00       0.00       0.00       0.00        0.00       0.76       2.54       0.00       0.76       0.00

            Rookery
              Total Rainfall        71.12       8.89      103.12     28.19       26.42    234.44     257.81      130.81     175.77      72.14
              Mean - Daily           2.29       0.25       3.30       1.02        0.76       7.87       8.38       4.32       5.84       2.29
              Median - Daily         0.00       0.00       0.00       0.00        0.00       0.76       3.81       0.00       0.76       0.00








                                                                                        26









       TABLE I. Results of storm 1 hydrograph analysis.




                                                                                  Total       Direct
                                                          Subbasin              Rgdnfall      Runoff    A
        Stream Gage/                                        Area                    P           R
        Subbasin                                     hectares ___(mi2)              (mm)      -(mm)
        Myakka City (2298608)
                                                     32376        (125)           188.2        18.8

        Myakka/S.R. 780 (2298700)
                                                     42737        (165)           153.2        38.1'

        Myakka/Sarasota (2298830)
                                                     59313        (229)           141.2         9.2

       .Myakka/Laurel (2298880)
                                                     65529        (253)           115.3        19.6

        Howard Creek (2298760)
                                                       5180       (20)            181.9         2.5

        Deer Prairie Slough (2299160)
                                                       8547       (33)             130.6        5.3

        Big Slough Canal (2299410)
                                                       9583       (37)              89.4       11.8

        Big Slough Canal North Port (2299455)
                                                     24088        (93)            104.9         8.5





                                                              28









             TABLE J. Results of storm 2 hydrograph analysis.





                                                                               Total       Direct        Total        Peak Flow       Time to
                                                       Subbasin               Rainfall     Runoff    Abstraction        Rate           Peak
               Stream Gage/                             Area       2)            P           R             F               p            Tp
               Subbasin                          hectares      (mi              (mm)        (mm)         (MM)          0/8)       -(hra)

               Myakka City (2298608)
                                                 32376         (125)            79.3        31.0          48.3          20.4            99
               Myakka/S.R. 780 (2298700)         42736         (165)           103.1        70.4          33.0          66.0           103
               myakka/sarasi,ta (2298830)        59313         (229)           102.4        14.7          87.6          11.5           155
               Myakka/Laurel (2298880)           65529         (253)           109.5        21.8          87.7          28.3            -

               Howard Creek (2298760)
                                                   5180        (20)            103.1        22.6          80.7           2.4            39

               Deer Prairie Slough (2299160)
                                                   8547        (33)              3.12        0.8          78.5           1.4            52

               Big Slough Canal (2299410)
                                                   9583        (37)             83.6         8.4          75.2           1.4           138

               Big Slough Canal North Port (2299455)
                                                 24088         (93)             81.8         7.4          74.4           3.4            30















                                                                                           29










         each hydrograph consisted of hourly and daily flow rates recorded
         at the respective station. Base flow volume was isolated from the
         plotted discharge curve by extending a horizontal straight line
         from the beginning point of the rising limb to a point of
         intersection with the receding limb. The area between the curve
         and this line was assumed to be the direct runoff volume (R)
         produced by the storm event.

              Rainfall hyetographs were then constructed for each of the
         hydrographs, based on daily rainfall records. The rainfall amount
         for each day was taken to be a simple arithmetic mean of
         measurements from selected monitoring stations associated with each
         subbasin. This method of rainfall calculation was considered to be
         adequate since the individual subbasins are of such large area that
         the ef fects of rainfall distribution would be of small consequence.
         The data consisted of daily rainfall totals only and included no
         information on variations of intensity within the 24 hour period.
         Since no hourly intensity data were available, rainfall amounts
         were presented as millimeters per 24 hours.


              Storm 1 Hydrograph Analysis

              Rainfall activity during the period of July 15 and August 9
         was typical for the southwest Florida region. Frequent, localized,
         @onvective storms produced wide variations in rainfall amount and
         intensity throughout the Nyakka basin.      Daily rainfalls ranging
         from 9.9 mm. to 71.6 mm were recorded at various monitoring stations
         throughout the basin.     The resulting runof f from these storms
         produced hydrographs that were in many cases multi-peaked, thereby
         yielding indistinct correlations between rainfall and runoff. The
         SCS method of analysis provides no means of partitioning combined
         flows represented by the multiple peaks, therefore, no attempt was
         made to calculate SCS comparison parameters. However, examination
         of these hydrographs did provide volumetric comparisons of total
         period rainfall and total direct runoff which were useful in
         understanding the retention characteristics of the subbasin.

              Storm 2 Hydrograph Analysis

              Rainfall activity during the period from September 22 to
         October 16 was much more stable than during the prior storm period.
         Rainfall occurred daily during a five day span from September 23
         until September 27 at all monitoring stations within the Myakka
         basin. Daily amounts ranging from 0.5 mm to 58.4 mm were recorded
         in the basin with fairly consistent distributions within each
         subbasin. This five day span had been proceeded by four days of
         zero precipitation, and was followed by ten days of zero
         precipitation. These periods of inactivity effectively isolated
         the f ive day storm thus providing an ideal situation for the
         creation of single-peaked hydrographs necessary for reliable SCS
         analysis.                        30









                The peak rate factor I'M was calculated for each storm 2
           hydrograph in an effort to characterize hydrograph shape and
           provide a means of comparison to the SCS unit hydrograph. This
           was accomplished by the use of the following relationship as given
           in SCS publication TR-55:
                                     K     (qP x TP)
                                            (A x R)


           where:


                                        = peak flow rate
                                     TP = time to peak
                                        =  basin area
                                     R = direct runoff

                In an effort to understand the -effects of ground cover and
           land use within the Myakka basin, SCS curve numbers (CN) were
           treated in the analysis of storm 2 hydrographs. From rainfall data
           and hydrograph runoff estimations, curve numbers were then back-
           calculated using two accepted SCS relationships detailed below.
                                           (P - .2S)2
                                     R     ----------                 (2)
           where:                          (P + .8s)

                                     R     runoff
                                     P     total rainfall
                                     S     potential abstraction


                Equation (2) is solved f or S, which is an estimate of the
           maximum retention for the basin. The curve number, which is an
           indication of the potential runof f of the basin, is inversely
           related to S by:
                                     CN     1000                      (3)
                                           (10 + S)

                A curve number was calculated for each hydrograph in this
           manner. The resulting values were then compared to accepted SCS
           values for the soil cover and land uses found in the basin.







                                            31










          Water Chemistry

              Sampling Periodicity

              Sampling was conducted throughout 1989 during 17 regularly
          scheduled sampling runs. Sampling periodicity was approximately
          every three weeks during periods of low rainfall (October - May)
          and every two weeks during periods of high rainfall (June -
          September). Sampling was conducted over a two day period; basin
          sampling on day one and estuary sampling on day.two.

              In addition to regular sampling events, sampling.was conducted
          during two storm events to,characterize loading rates during high
          flow periods. To accomplish this, several samples were collected
          at each site over a short time period. Samples were collected
          during the rising arm of the hydrograph (n=3), at the peak (n=l)
          and during the declining arm (n=3).

              To obtain the desired distribution of samples across the
          hydrograph, historic rainfall events were compared with their
          associated hydrographs.   In addition to amount and duration of
          rainfallf factors such as stream stage, channel morphology and
          depth of the water table can influence hydrograph behavior.
          Therefore, separate analyses were conducted for several stations.
          This resulted in sampling regimes that were specific for each site
          (Table K).


              Station Locations

              A total of eighteen sampling stations   were monitored; eight
          within the river basin (basin sites) and ten in the estuary and
          tidal portion of the river (estuary sites) (Figure 7). Appendix A
          contains a description of the sampling locations. Stations within
          the basin were chosen so that subbasin water quality could be
          characterized.   Sampling was done in close proximity to USGS
          continuous record gaging stations so that nutrient loading rates
          could be determined. Project personnel were not allowed access to
          one gaging station that is on private property, therefore one
          station (B170), was located approximately 1.2 kilometers downstream
          of the corresponding gaging station. on each sampling date, basin
          sampling began at the northern part of the watershed and proceeded
          south.

              Eight of the ten estuary sites were related to monitoring
          sites established by Mote Marine Laboratory for wet and dry season
          characterizations of the Myakka River (Estevez 1985; 1986). These
          sites ranged from Charlotte Harbor to the "big bend" area (River
          miles -2.1 to 16.2). The locations of the remaining two stations
          ("floating" stations) were determined in the field from salinity
          data obtained from the eight fixed stations. These stations were
          chosen such that there were no large gaps in salinity between

                                          32





            TABLE K. Determination of days to Peak and fall for selected storm events

                                             8110                              8120                             B140
                               Days to Days to                    Days to Days to                    Days to Days   tc
                                 Peak        Fall      Total          Peak     Fall     Total            Peak  Fall
                                    3        5         a              3        7        10               4       9
                                    2        6         a              2        3        5                5      12
                                    3        9         12             1        5        6                7      16
                                    4        10        14             4        4        a                5      6
                                    2        7         9              2        7        9                4      is
                                    5        7         12             3        4        7                7      16
                                    2        9         11             3        2        5                5      13
                                    5        6         11             1        6        7                6      10
                  Mean            3.3        7.4       10.6           2.4      4.8      7.1              5.4   12.5
                  Minimum           2        5         3              1        2        5                4      6
                  Maximum           5        10        14             4        7        10               7      28
                  Std. Dev.       1.2        1.7       2.0            1.0      1.7      1.7              1.2   3.s


                                                         8150                               B160
                                                Days to Days to                   Days to Days to
                                                       Peak  Fall Total                 Peak    Fall Total
                                                       7     7        14                6       9        is
                                                       2     6        a                 7       16       23
                                                       2     2        4                 9       6        15
                                                       2     6        8                 S       14       19
                                                       4     5        9                 5       10       15
                                                       2     5        7                 11      14       25
                                                       1     6        7                 7       12       19
                                                       5     7        12                6       15       21
                 Mean                                  3.1  5.5   8.6                7.0     12.0    19.0
                 minimum                               1     2        4                 .5      6        15
                 Maximum                               7     7        14                Ll      16       25
                 Std. Dev.                             1.9  1.5   2.9                1.9     3.2     3.6

                                                                        33








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                                                                         -Lo
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                                                                                                   @ I
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                                     At                                                                    .10                                  -  $
                                                                                      TOT


                                                                                rf
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                                                                                                                       41         0     0
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                                                                             07  v
                                                                                                   IAIC                    Al
                                                                                                   I                   led

                                                                                                    ir

                                       14                                                     a
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                              101                                                                                                                 lot,


                                                                     X.
                                           %                fij   i     I I, . I,    -             1. 1    ,.d&        :.4,   I -            . 0
                                                                                             P.





                                                         P,
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                                                                                                           0
                                                                                                           0

                                                                                                           7
                                 tu                                                                    fe      So
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                                                                                                                       04IN0    oo

                                      Ik
                                                                                                                I, r
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                                                                                                                  --A

                       FIGURE 7. Location                     of basin and                 estuary         sampling sites.


                                                                                         34









           stations. In general, the floating stations were located so that
           at least four stations were in the 0 to 10 ppt salinity range.
           Sampling in the estuary began at the southern most station and
           proceeded upstream. Generally, sampling was done through a rising
           tide and a slack high tide.

                Sampling Methods and in-situ Measurements

                Measurements    of   dissolved    oxygent    temperature,     and
           conductivity at basin sites were taken at 0.5 m,  or at mid-depth if
           the water depth was too shallow at allow for      readings at 0. 5 m
           without disturbing bottom sediments. At estuary sites, a vertical
           prof ile was taken at 0. 5 ra intervals for dissolved oxygen,
           temperature, conductivity and salinity. Measurements were taken on
           the downcast and the upcast.

                Measurements were taken with YSI Model 33 S-C-T meter and
           Model 57 dissolved oxygen meter with a remote stirrer. Meters were
           calibrated in the laboratory prior to sampling. The D.O. meter was
           calibrated in chlorine-free, distilled water by Winkler titration
           (EPA method 360.1). Air calibration was checked at every site, and
           recalibration was done as necessary. The SCT meter was checked in
           the lab against a KC1 standard.

                Water samples at basin sites were collected at mid-depth with
           an Alpha Bottle (Wildco). When water depth was too shallow for
           alpha-bottle use without disturbing bottom sediments, samples were
           collected by hand-dipping sample containers. Hand-dip samples were
           taken facing the flow of the water. Estuary water samples were
           collected at mid-depth when the water column was vertically mixed.
           When the water column was stratified (defined as a 3 o/oo or
           greater change in salinity or 1.5 mg/l or greater change in
           dissolved oxygen over a 0.5 meter or less change in depth) , samples
           were collected at the mid-depth of both strata.

                Water samples were poured directly into clean 1/2 liter
           polyethylene bottles.    Replicate samples were collected at each
           station.   pH readings were taken from each sample by pouring
           approximately 15 ml of the sample into a clean 30 ml container. pH
           was measured with a Beckman Model 10 digital pH meter. The meter
           was 2-point calibrated in the lab and I-point calibrated (pH 7.0)
           at every site.    Water samples were immediately put on ice and
           delivered to the Mote Marine Laboratory after sampling was
           complete, usually within two hours.

                Wind speed and direction were measured at an exposed site
           near the sampling location. Wind speed was measured with-a hand
           held (Dwyer) wind gage,'and wind direction was measured with a hand
           held compass.      Air temperature was measured by placing a
           thermometer in a non-enclosed area away from direct sunlight.



                                            35










          Cloud cover and other pertinent meteorological information were
          recorded. Station depth was recorded with a lead line marked in
          meters.

                In addition, Secchi disk depths were taken at all estuary
          sites.    Measurements are made with a 50 cm oceanographic-style
          disk.   Secchi disk depths were measured for both the white and
          black sides of the disk.

                Laboratory Analysis

                The parameters analyzed and the methods used are listed in
          Table L. Note Marine Laboratory analyzed all parameters except
          particulate nitrogen and carbon.        For particulate nitrogen and
          carbon analyses, 250 ml of sample water was filtered through
          precombusted glass f iber filters (Gelman A/E 2 5 mm) . Filters were
          rinsed three times with 10 ml of deionized water, folded with the
          residue inward and wrapped in precombusted foil. The filters were
          frozen, packed on dry ice and shipped overnight to the SWFWMD
          laboratory for subsequent analysis.


          TABLE L. Chemical parameters and methods used for analysis.


                Parameters                            Methodsi         units



          DISSOLVED COMPONENTS

                Ammonium-Nitrogen                     SM   417F        mg-N L-1
                Total Kjeldahl Nitrogen               EPA  351.2       mg-N L-'L
                Nitrate-Nitrite-Nitrogen              EPA  353.2       mg-N  L-1
                Orthophosphorus                       EPA  365.1       mg-P  L-1
                Organic Carbon                        EPA  415.1       mg-C  L-1

          PARTICULATE COMPONENTS

                Total Phosphorus                      EPA 365.1        mg-P  L-1
                Total Carbon                          P.E.             mg-C  L-1
                Total Nitrogen                        P.E.             mg-N  L-1

          OTHER

                Total Suspended Solids                SM 209D          mg    L-1
                Turbidity                             EPA 180.1        NTU



           SM = Standard Methods, 15th Ed; EPA = EPA 600/4-79-020 Methods for Chemical Analysis of
          Water and Waste Water; P.E. = Perkin-Elmer Model 2400 Elemental Analyzer Manual.


                                             36









           Nutrient Flux Analysis

                The data for water from seven of the eight stations sampled
           were evaluated to determine f luxes of materials (nutrients and
           solids) from the various subbasins of the Hyakka River Watershed
           and to elucidate processes influencing the transport of these
           materials.   The reason for using results from only seven of the
           eight stations is that discharge data for them (all except B130)
           were available for the entire study period along with water
           chemistry. Data on water chemistry collected from storm sampling
           campaigns were used to assess the importance of storm events on the
           fluxes, (i.e., to see if these events produced more efficient
           delivery effects).    Water chemistry of samples collected from
           monthly transects of the Myakka River estuary were compared to that
           of the freshwater sources in the watershed to evaluate processes
           affecting transport and removal of materials in the estuarine
           environment.

                The following sections describe methods used to reduce and
           analyze the data for the purposes described above.


                Estimates of Annual Material Flux

                The flux or load of a chemical substance transported from
           subbasins of the Myakka River watershed is simply the product of
           the chemical concentration and water discharge.        Instantaneous
           values of flux are relatively simple to derive for each river
           station using measured substance concentrations and instantaneous
           or daily mean discharge at the time of sampling. It is much more
           difficult to estimate, with a high degree of accuracy, fluxes over
           longer periods of time such as a year or more since this requires
           long term records of concentration (C) and discharge (Q), so the
           flux (F) can be calculated by  integration using the equation:


                                    F = f CQdt (1)
                                         0


                It would be easy to calculate fluxes if concentrations of
           substances were constant over all variations in discharge. This,
           however, is not the case since the concentrations of virtually all
           substances, both particulate and soluble, vary with discharge.
           Nonetheless, several approaches have been used to calculate f luxes
           with limited data collected over various flow conditions of a
           watershed.     Generally, the approaches used involve either
           extrapolation or interpolation of the data.         Each of these
           approaches is discussed below.



                                           37










               Extrapolation Method for Estimating Material Flux

               This procedure attempts to extrapolate the available database
          by   developing   rating   relationships   which    link    chemical
          concentrations measured at infrequent intervals to stream discharge
          at the time of sampling.       Rating relationships are normally
          developed for sites with discharge monitoring facilities so that
          the rating function may be applied to a continuous flow record,
          thus allowing for extrapolation of chemical concentration (and
          flux) between periods of sample collection. Simple power functions
          of the form:

                               Concentration = aQb (2)

          are used to relate the concentration of a substance and river flow,
          Q.   Such relationships have been routinely documented by many
          studies. For example, suspended sediments generally show increased
          concentration with discharge following a relationship described in
          equation (2) with b being a positive number. In the case of total
          dissolved solids, a similar relationship is observed, but b is
          sometimes negative (Figure 8).    Rating relationships or rating
          curves have been demonstrated for many specific substances, for
          both natural and anthropogenically disturbed (e.g., agricultural
          areas) watersheds (Nilsson, 1971; Turvey, 1975; Walling and Webb,
          1983; Walling and Kane, 1984).

               Although rating relationships for total dissolved solids often
          exhibit decreasing concentrations with increasing discharge
          typically due to dilution, specific dissolved substances such as
          nutrients often show increases with discharge (Walling and Webb,
          1984; Webb and Walling, 1985).

               Rating curves are developed by obtaining concentration data
          over seasonal variations in discharge for a given watershed.
          Fitting concentration data to discharge is usually accomplished by
          least-squares regression techniques. This approach was employed in
          the present study using the observed concentrations of constituents
          and mean discharge for the station on the day of sample collection
          and applying a log transformation of equation (2).

               other authors (e.g., Jansson, 1985) have argued that other
          methods of curve fitting are more appropriate, and in some cases
          (e.g., Hall, 1970; Davis and Zorbrist, 1978; Foster, 1980), the
          relationship between concentration and discharge will not be
          described by a simple power function. Given the limited data set
          for each station, the least-squares regression approach used in
          this study is more appropriate.

               Many   investigators  have   stressed   the   complexity    and
          variability of storm-period sediment and solute responses to
          discharge (Miller and Drever, 1977; Walling and Foster, 1978;
          Foster, 1978a,b; Reid et al., 1981, Dupraz et al., 1982; Webb and

                                          38










                                    saw


                                    Cx     IC%ft
                                    E
                                    %wo

                                    C
                                    0
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                                    41M.
                                    C


                                    C



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                                    C                                 COW.'.0w.
                                    e  Ile                            W^*
                                    E                                w



                                                                     11 Co..






                                    C
                                    0  it
                                    Q             do
                                    zo       son
                                    co       Discharge (m3s-1km-2)

                    b)

                            5000-
                        E

                                                    see
                           1000- Dolores River
                        M
                                    near Cisco. Utah.
                        E    500-   USA
                                                                    1619

                        C
                        0

                             100-

                              50-
                                                                 C   5
                                                                     30-0094
                        '0          8iver Barle. at Brushford.
                        0           Somerset. UK
                        M    10 1       1   1       1  1       1           1  i
                        An      0.1         1         410        100        1000
                                                            3 -1
                                               Discharge (M s

              FIGURE S.  Concentration-diadharge         rating    relationship      for.
                         dissolved,     particulate     and    particulate-associated
                         substances in rivers (after (a) Walling and Webb, 1983
                         and (b) Walling and Webb,, 1981).

                                                   39









           Walling, 1983; Walling and Webb, 1986a,b). Thus, it is important
           to   determine   concentration    relationships    to     storm-related
           variations in flow. In practice, for a given watershed, separate
           rating curves can be developed for seasonal flow and storm-related
           flow.  For this study, however, the data collected during storm
           events were combined with the data from the periodically collected
           routine samples.

                Once the rating curves are developed (assuming the least
           square relationship is significant), annual flux of a given
           material by each river is calculated using the f6llowing equation,
                                          n    b+1
                                   Flux = I aQi   t (3)
                                         i=1
           where Q, is the mean    daily discharge recorded at the specific
           stream gauge, n = 365,  a and b are constants derived from the least
           square regression analysis of concentration on discharge, and t is
           the time over which Q, is averaged.

                Interpolation Method for Estimating Material Flux

                Several interpolation procedures have been used for estimating
           total loads or fluxes of materials. Five representative numerical
           procedures are listed in Table M.         These procedures make the
           assumption that the chemical    concentration of a water sample is
           representative of conditions in the river for the period between
           sampling.    These approaches essentially attempt to weigh the
           concentration to discharge.     For the present study, Method 5 was
           used. For each parameter, the calculations were carried out using
           the results from all samples collected January through December
           1989. For these calculations,   n generally was around 30-35 and the
           conversion factor K was adjusted for a discharge record of 12
           months.

                Estuarine Chemistry

                Advection-diffusion   models have    been used by many inves-
           tigators to interpret estuarine chemical data (e.g., Li and Chan,
           1979; Kaul and Froelich, 1984).      These models use salinity as a
           tracer. The distribution of a constituent in estuarine waters can
           be compared to salinity to determine whether a substance is: 1)
           conservatively transported throughout the estuary, 2) removed from
           the water column or 3) added to the water column due to local input
           (e.g., anthropogenic, release from sediments, etc.). These types of
           estuarine behaviors are demonstrated in Figure 9.

                From the advection-diffusion models using salinity as a
           conservative tracer, the intercept of the extrapolation (or
           tangent) of the constituent-salinity curve at the high salinity end
           of the curve where change in constituent concentration with change
           in salinity is constant, is defined as the apparent zero salinity

                                             40








            TABLE M. Interpolation methods for flux calculations.






                    Method                                Numerical Prowdute
                                                     rk  C      01
                                     101AL  1LOAt, K(x     H    - )
                                                              W, n

                                                            C,
                                     IVIAL LOAD   K01
                                                            n

                                                    n   C 0
                                     IDIAL LOAD - KI
                                                         n

                                    IDIAL LOAD - KIE PIC)P

                                    IDIAL LOAD -   Ki11(Ci0J   or
                                                      n
                                                      I 0j
                                                     1=1


                                CouviRsjoh rwor. ID 1AVE Arcouki or PLRJOV or Rt CORD


                        It   a  INSIANIANEDUS CONUNIRAIM ASSUMED UJIM      3NDIVIDUAL SAMPIAS

                             &  INSIANIANEDUS DISCHARGI Al 1JM1 01 SAMPL11NG


                                N:&k DISCHARCl FDA pIRIOD or RICDR.,@


                         g.    K-*Ak DISCHARGI FOS INIERVAL 9111(110o SAMPLfS

                               hUmfirli or SAmPLtS









                                                   41




















                                                                      30
         a)                                         A Z E.               0
          -300-
                                                                      20

          U200-                                                          0
         =L        AZE                                               -10 ZZ
          0100-                                                          P7
         U-
              0-                                                     -0
               0     10     20     30           0   10   20   30




                         C)     AZE

                          10





                         0
                         E 5-
                         C





                           0
                             0      10     20      30
                                    Salinity (%o)




         FIGURE 9. Examples of different estuarine behavior of trace metals:
                   (a)   removal  (after Figueres    et al.,    1978;  (b)
                   conservative; and (c) release (Windom, unpubl. data).

                                        42









           end-member (AZE) . It can be demonstrated mathematically that river
           discharge multiplied by the difference in the observed zero
           salinity concentration and the AZE value gives the rate of removal,
           or release, of the constituent, per unit time, necessary to produce
           the observed concentration distribution.       The only assumption
           required is that the concentration of the constituent in the
           freshwater input is constant over the residence time of the
           estuary.    For the Myakka River estuary, this assumption is
           satisfied sufficiently to draw the conclusions that will be made.

                Following the approach described above (advection-dif fusion
           model) , monthly data for concentrations of dissolved nitrate +
           nitrite (N03+NO 2)1 orthophosphate Rod 1  organic carbon (DOC), and
           ammonia; total suspended solids (TSS) ; and particulate organic
           carbon (PC) , nitrogen (PN) and phosphorus (PP) were plotted against
           salinity. Concentration of all freshwater samples taken during the
           same sampling period is also plotted as the freshwater end members.


           Sediment Chemistry

                Sampling Locations

                Sediment samples were collected from four stations in the
           Myakka River and one station in Charlotte Harbor at the mouth of
           the Myakka River in November 1989.     At the same time, sediments
           were collected from several other stations in the Peace River and
           upper Charlotte Harbor.     Data from some of these stations are
           included in this report for comparison with data from the Myakka
           River. Station locations for all sites are listed in Table N.


           TABLE N.  Dates and location for Myakka River, Peace River and
                     selected Charlotte Harbor sediment sampling stations.

           STATION      DATE     LATITUDE   LONGITUDE               LORAN


           MYK-1      11/07/89   27 01.94   82 15.20      30869.2    44164.1
           MYK-2      11/07/89   27 04.25   82 18.81      30871.6    44206.7
           MYK-3      11/07/89   27 03.24   82 17.59      30869.6    44191.1
           MYK-4      11/07/89   27 00.98   82 16.33      30861.4    44168.7
           PER-1      08/29/85   26 57.08   82 03.25      62681.9    44037.8
           PER-1      11/07/89   26 57.01   82 03.21      30874.9    44037.5
           PER-2      11/07/89   26 59.65   81 59.79      30896.4    44021.0
           PER-3      11/07/89   26 58.20   82 00.65      30887.2    44021.3
           CHH-2      07/13/85   26 54.65   82 09.67      30846.8    14165.1
           CHH-2      11/07/89   26 54.65   82 09.67      30846.8    44081.2
           CHH-7      09/24/86   26 51.17   82 08.95      14158.6    44058.9
           CHH-7      11/09/89   26 51.17   82 08.95      30831.2    44059.0
           CHH-19     11/08/89   26 55.18   82 10.96      30846.2    44094.7
           CHH-20     11/08/89   26 54.44   82 10.58      30843.4    44087.9


                                            43










               Sampling Methods

               Sediments from all stations were analyzed for nutrients and
          metals.   In addition, several classes of organic compounds were
          measured in the samples from stations MYK-1 and MYK-3. FDER had
          previously collected sediment chemistry data from other stations in
          Charlotte Harbor and the Peace River (locations listed in Table N)
          these data are also presented in this report.

               Sediments were collected with a stainless steel Ponar grab.
          The grab samples represented surficial sediments to a depth of
          approximately 5 cm. At each station, triplicate grabs were taken
          and two were analyzed. The third sample was held in reserve in the
          event of sample loss.

               All samples were placed in pre-cleaned containers, stored on
          ice, and shipped to the Savannah Laboratories and Environmental
          Services (SL&ES, Savannah, GA) for processing within 24 hours.

               Laboratory Analysis

               Metals. Sediment metal concentrations were determined for ten
          metals: aluminum, arsenic, cadmium, chromium, copper, lead, iron,
          mercury, nickel, and zinc. For all metals except mercury, sediment
          was dried at 800 C, thoroughly mixed, and a 0.3 to 0.5 g portion
          weighed into a 100 ml polytetrafluoroethylene vial.      Five ml of
          Ultrex HF and 10 ml concentrated Ultrex HN03 were added, the vials
          capped, and the sample digested by refluxing at 1000 C for 48
          hours. After digestion, the sample was taken to dryness and the
          residue dissolved in I ml concentrated Ultrex HN03 and 9 ml
          deionized, double distilled water.     Total digestion using HF is
          essential for releasing all metals from aluminosilicate mineral
          lattices. Sediment samples for mercury were first digested with
          HZS04 and HN03 in a water bath at 600 C and then further oxidized
          with potassium permanganate.

               Aluminum and zinc were analyzed using flame atomic absorption
          spectroscopy (AAS) . Cadmium, chromium, copper, lead, and nickel
          were analyzed by flameless AAS using a Zeeman furnace. Flameless
          AAS methods were used for arsenic (hydride) and mercury (cold
          vapor). The AAS methods are described in APHA (1985).

               Duplicate laboratory analyses and spikes were performed on 10%
          of all samples.    National Bureau of Standards (NBS) Estuarine
          Sediment Standard Reference Material 1646 was run with each batch
          of sediment samples. Analyses of all sediment samples in a batch
          were repeated if analytical results of the Standard Reference
          Material deviated by more than two standard deviations (lab
          results) from the mean reported by NBS.




                                           44









                Nutrients.    Total organic carbon (TOC)      total Kjeldahl
           nitrogen (TKN) and total phosphorus (TP) were determined according
           to methods described in APHA (1985).

                organics.     Chlorinated pesticides and polychlorinated
           biphenyls (PCB) were analyzed by Method 608 (40 CFR, Part 136).
           Semi-volatile organics and polynuclear aromatic hydrocarbons (PAH)
           were analyzed by Methods 8270 and 8310 (EPA SW 846), respectively.
           The compounds measured and detection limits are listed in Table 0.











































                                           45










         TABLE 0. organic compounds measured and detection limits for July
                   1985 (CHH-2) and November 1989 (KYK-1, MYK-3) sediment
                   samples.


                   Compound                            Detection Limit


         Station CHH-2, July 1985

              Polynuclear Aromatic Hydrocarbons (PAH)
                   Acenapthene                             0.1 mg kg
                   Acenapthylene                           0.1,
                   Chrysene + benzo(a)anthracene           0.2
                   Benzo(a)pyrene                          0.2
                   Benzo(b,k)fluoranthene                  0.2
                   Benzo(g,h,i)perylene                    0.4
                   Fluoranthene                            0.1
                   Fluorene                                0.1
                   Indeno(1,2,3-cd)pyrene
                    + Dibenzo(a,h)anthracene               0.4
                   Napthalene                              0.1
                   Pyrene                                  0.1
                   Phenanthrene + anthracene               0.1



         Stations  MYK-1, MYK-3, November 1989

                   Chlorinated Pesticides
                   Aldrin                                 1 pg kg'l
                   alpha-BHC                              1
                   beta-BHC                               1
                   delta-BHC                              1
                   gamma-BHC                              1
                   Chlordane                              10
                   4,41-DDD                               2
                   4,41-DDE                               2
                   4,41-DDT                               5
                   Dieldrin                               2
                   Endosulfan 1                           2
                   Endosulfan 11                          5
                   Endosulfan sulfate                     5
                   Endrin                                 2
                   Endrin Aldehyde                        5
                   Heptachlor                             1
                   Heptachlor epoxide                     2
                   Kepone                                 5
                   Methoxychlor                           10
                   Toxaphene                              20





                                         46









           TABLE 0. (continued)


                     Compound                               Detection Limit


                 Polychlorinated biphenyls (PCB)
                     Aroclor  1016                              5 pg kg-1
                     Aroclor  1221                              5
                     Aroclor  1232                              5
                     Aroclor  1242                              5
                     Aroclor  1248                              5
                     Aroclor  1254                              5
                     Aroclor  1260                              5

                Aliphatic hydrocarbons
                     CIO aliphatics                           25  ug kg"
                     CII aliphatics                           25
                     C12 aliphatics                           25
                     C13 aliphatics                           25
                     C14 aliphatics                           25
                     C15 aliphatics                           25
                     C16 aliphatics                           25
                     C17 aliphatics                           25
                     C18 aliphatics                           25
                     C19 aliphatics                           25
                     C20 aliphatics                           25
                     C21 aliphatics                           25
                     C22 aliphatics                           25
                     C23 aliphatics                           25
                     C24 aliphatics                           25
                     C25 aliphatics                           50
                     C26 aliphatics                           50
                     C27 aliphatics                           50
                     C28 aliphatics                           50
                     C29 aliphatics                           50
                     C30 aliphatics                           50

                Polynuclear Aromatic Hydrocarbons (PAH)
                     Acenapthene                              40 jLg kg
                     Acenapthylene                            40
                     Anthracene                               40
                     Benzo(a)anthracene                       40
                     Benzo(a)pyrene                           40
                     Benzo(b)fluoranthene                     40
                     Benzo(g,h,i)perylene                     40
                     Benzo(k)fluoranthene                     40
                     Chrysene                                 40
                     Dibenzo(a,h)anthracene                   40
                     Fluoranthene                             40



                                             47










         TABLE 0. (continued)


                  Compound                             Detection Limit

                  Fluorene                               40
                  Indeno(1,2,3-cd)pyrene                 40
                  Napthalene                             40
                  Pyrene                                 40
                  Phenanthrene                           40
                  I-Methylnaphthalene                    40
                  2-Methylnaphthalene                    40
                  Benzonitrile                           85
                  Quinoline                              85
                  Quinaldine                             135
                  8-Methylquinaline                      85
                  7,8-Benzoquinoline                     85
                  2,4-Dimethylquinoline                  135
                  Acridine                               135
                  Carbazole                              85










































                                         48













          IV. RESULTS

          Rainfall and Hydrological Results

               Rainfall

               Appendix B contains a detailed listing of monthly rainfall
          levels for the period of record at the long-term rainfall station.
          Rainfall for the 1989 study period was below the mean for the
          period of record at all long-term rainfall stations. Annual
          rainfall for two long-term rainfall stations within and near the
          study area is shown in Figure 10.     Rainfall in 1989 at the NOAA
          station in Myakka River State Park was 256 mm below the mean for
          the period 1944 through 1989.       A comparison of mean monthly
          rainfall for the period of record with monthly rainfall for 1989
          indicates that lower than average rainfall in the late winter and
          spring, particularly during February and May, contributed greatly
          to the low rainfall in 1989 (Figure 11).

               spatial variability of rainfall inputs within the watershed is
          high, especially during summer months when rainfall results from
          highly localized convective storms. Figure 12 shows 1989 monthly
          rainfall for June through September from six sites within the
          basin. Most sites are within four miles of each other (Figure 6).
          Not only do the sites vary in rainfall amount, the relationship
          among sites is not consistent from month to month (i.e., site 1
          does not always receive more rainfall that site 2).

               Hydrology

               Hydrographs for the seven gauged streams during the period 1
          October 1988 to 30 September 1989 are shown in Figure 13. These
          data indicate that the general seasonal discharge patterns of all
          subbasins are similar with a well defined low flow period between
          November and June and a high discharge period during the remainder
          of the year.

          Storm Hydrograph and Rainfall

               Myakka City (B110)

               Gaging Station #2298608 is located at the State Road 70 bridge
          near Myakka City. This is the furthermost upstream station on the
          main body of the River and monitors a watershed of 32,376 ha. The
          watershed is quite wide for its length and is drained by numerous
          streams.   It contains several large areas of potential surface
          retention in the form of depressional wetlands.

               The storm 1 hydrograph (Figure 14) for this gage was
          characterized by a series of three distinct peaks. All of these
          exhibited shapes characteristic of a wide watershed with steep-
          sloped rising limbs followed by receding limbs of fairly constant

                                           49





                    a)                                            Total Yearly Rainfall
                                                                   Fort Green. Florida
                          2400


                          2200                                                                         -LWAN- 1351


                          2000


                          1800


                          1600


                          1400

                     E
                          1200


                          1000


                          800


                          600


                          400


                          200

                            0                                            1

                                1956        1960          1964          1966'        1972               1985           i989
                          b)                                         Total Yearly Rainfall
                                                                   Ujakka River State Park
                              25W

                                                                                                      -MEAN- 1422
                              2250  -



                              2000  -



                              1750  -



                              1500  -

                          E
                              1250  -



                              1000



                              750



                              500



                              250


                                 0  ..................              ..........                             ........

                                    19"  1948   1952   1956    Igeo    1964 19se      1972   1976    1980    1984 1.988


                 FIGURE 10. Long-term annual rainfall for (a) Fort Green and
                                     (b) Myakka         River State Park.


                                                                          n





             300



             270 -



             240 -
                                                                       ..........



             210



             180
          E
          E
             150

         4-


             120



               90



               60
                                            ..........



               30




                              F     M      A     M            i      A      S      0

                                                         MONTH
       FIGM 11.        Comparison   of mean monthly rainfall    for  1944-1989 (triangles)
                       rainfall for 1989 (bars) at myakka River      State Park.

                                                        51







                        400


                                      4
                        360           3

                                      XS3
                        .320          112
                                      X134


                        280


                    E
                    E   240


                    M
                    a   zuu
                    ix



                        160



                        120



                          80



                                        June                      July                       August

            FIGURE 12.           Variability of rainfall for June through September, 1989 at
                                 the watershed.
                                                                    RM


                                                                    RM







                                                                    NM
                                         SM                         RM
















                                                                          52






                     B110                                     8160


                jaCCM                                    go=



                  0
                  M         40   so    M                              AN   M



                OMM
                2MM  B120                                      B170

                                                         loom

                mom
                                                           4Mw








                                                         am=
                jc@. B140                                mom   B180

                Gomm                                     am=


                                                           OL          -A
                            410        so                   M              M



                OMM  . . . . . . .
                  . B150                                 Day=275  Date: 10/1/88
                Soo=
                                                         Day=641  Date: 9/30/89'
                mom




                  M         An    M    M



       FIGURE 13.   Seasonal variation in discharge at subbasin stream gaging stat

                                                 53






















                               7/15/al    7/16/69   7/17/611  7/18/19    7/19/59   7/20/69    7/21/89   7/32/09    7/23/89   7/24/Be    7/25/ag   7/26/60    7/27/5,   7/26/89    7/22/89    7/30/09   7/31/69    6/1/82     8/2/09    6/3/89     0/4/8
                            25

                            24

                            23

                            22

                            21
                   LO       20

                            12
                   E        'a
                            17
                   Li       Is
                   0        15
                   C)@      44
                   <        13


                   cn
                   F@       to



                   W                                          --- 1\
                                                                                                    ..........................................             .............................................
                   cn                                                                                                                                                              (Bosenow)                           .........................




                             a         24        44        72         96        120        1.,       166        192       216       240        76.       268        312        &W        360        M4        406        432        4w        00
                                                                                                                                                       TIME (HOURS)





                            FIGURE 14.                          Myakka City (B110) - Storm 1.

                                                                                                                                                            54










         slope. This indicates that an initial surge was produced by excess
         runoff from areas near the basin outlet but drainage quickly became
         uniform after peak flow (qP) had been reached.
               A high base flow remained constant at this station during most
         of the study period and was estimated to be 5.2 cms.                 Each
         succeeding peak rose more sharply from this with the advent of an
         intense rainfall event. This illustrates the steady increase in
         soil moisture produced by the frequent low intensity rainfall which
         occurred throughout the study period.

               Total rainfall (P) for this storm period was estimated to be
         188.2 mm based on records of the Fort Green monitoring station and
         the monit'oring station at the North entrance of Myakka River State
         Park. Direct runoff (R) for the period, as indicated by the storm
         hydrograph, was 18.8 mm, yielding an abstraction (F) of 169.4 mm.
         Thus, 90 percent of the estimated excess rainfall was retained in
         the watershed.

               The storm 2 hydrograph (Figure 15) for this station was
         single-peaked with a peak flow (%) of 20.4 cms.          This peak was
         similar in shape to those of the storm 1 hydrograph except that it
         had a narrower base. Examination of the rainfall records indicated
         that antecedent soil moisture levels were high prior to the second
         storm, accounting for the more rapid increase and recession of flow
         rate (q P)
               Total rainfall (P) for this period was estimated to be 79.3
         mm. Examination of the hydrograph indicated that 31.0 mm of direct
         runoff (R) was produced by the storm yielding a 61 percent
         retention rate with a total abstraction (F) of 48.3 mm.               The
         difference in abstraction between the two storms illustrates that
         the level of soil moisture has a significant bearing on the
         retention capacity of this subbasin.

               The peak rate factor (K) for this hydrograph was found to be
         0.73. This closely compares to the SCS Unit Hydrograph model peak
         rate factor (K) of 0.75, which indicates that the SCS model could
         closely approximate runoff behavior for events similar to this
         storm.

               The curve number (CN) was back-calculated as described
         previously.    Assuming medium antecedent moisture conditions, a
         value of 84 was obtained. According to SCS guidelines, the poorly-
         drained sand covering much of the Myakka basin would fall into soil
         groups B or C. Appropriate curve numbers for open areas with this
         type of soil cover would range from 61 to 86, depending on land
         use.      Therefore,    SCS   guidelines    would    provide    adequate
         determination of curve numbers for this subbasin.

               Under low antecedent soil moisture conditi     ons this subbasin
         has high retention capacity due to a combination of large

                                            55





















                          0/7z/so           9/24/89  1/25/81   9/26/19  0/71/59  9/28/09            9/30/62   10/1/59  10/2/ge  10/3/so  10/4/89   10/5/69  10/s/So  10/7/811  SO/s/69  10/t/09  101/10/89 to/11/69 1 CA 2/119
                       23                             NIM     1".1w                                                                                                                          -1==@
                       24

                       23

                       22

                       21

                       10

                       to
               E       is
                       17

                       Is

                       15
               (Y      14
               <       13


                       it
               0       10
               :2      :
               <       7
               Lu
               of

               Cn      4

                       3

                       2
                                                   .............................................................................                      ................................       ..........................


                        0        24       40                Is       120      144       IGO      tol      214       240      364      3"        317      3M       AO       364       40       432       456      460
                                                                                                                                    TIME (HOURS)





                       FIGURE 15.                          Myakka City (B110) - Storm 2.

                                                                                                                                         56









         depressional surface storage areas and the in-situ water storage
         capacity of the soil cover. However, during extended periods of
         frequent precipitation this storage is lost and short flow peaking
         times and high peak flows can occur. This is due mainly to ef fects
         of the relatively short, wide watershed which tend to decrease
         concentration times.

              Myakka River at S.R. 780 (B130)

              Gaging station #2298700 is located at the State Road 780
         bridge, near the north entrance of the Myakka kiver State Park.
         This watershed includes the Myakka City subbasin plus an additional
         10,361 ha for a total area of 42,737 ha. Significant portions of
         this area are cultivated and have been ditched to provide
         irrigation and drainage. Tatum Sawgrass is partially drained by
         branches upstream of the gaging station which have a noticeable
         effect on streamflow activity.      The portion of the watershed
         downstream from Myakka City narrows sharply due to the presence of
         numerous small streams which meander away from the main channel in
         both easterly and westerly directions but eventually join the river
         downstream of the gaging station.

              The hydrograph for this storm I (Figure 16) was composed of
         two low, wide based peaks, the largest of which reached a maximum
         flow rate (q ) of 34 cms. These peaks corresponded to two separate
         and distin&? periods of rainfall. However, as a result of overlap
         of the two events, accurate calculation of SCS parameters was
         impractical.    Comparison of this hydrograph to the storm 1
         hydrograph of the Myakka City station shows that the short rise
         time (Tr) observed in the Myakka City subbasin had been moderated
         substantially by passage through the additional watershed. This
         results from the narrow shape of the additional drainage area which
         tends to increase the distance that runoff must travel from the
         upper reaches of the watershed while adding only a small amount of
         catchment surface near the gaging station.

              Total rainfall (P) for this storm period, based on data taken
         at the North Entrance monitoring station, was estimated to be 153.2
         Mm.   Direct runoff (R) was estimated to be 38.2 mm with an 82
         percent abstraction (F) of 125.3 mm. This high abstraction was a
         product of low antecedent soil moisture conditions that existed
         prior to the storm events, and reflects the 90 percent retention
         rate observed in that portion of the watershed monitored by the
         Myakka City station.

              The storm 2 hydrograph (Figure 17) for this station is a
         single-peaked curve with rising and receding limbs of nearly- equal
         slope. Peak f low (qp) for this event reached 66 cms with a time to
         peak (Tp) of 119 hours. The peak exhibited a shorter base width
         than the peaks of the storm 1 hydrograph, reflecting an increased
         ground moisture content and subsequent loss of basin retention
         capacity. Further illustration in the loss of retention capacity

                                          57



















                                             7/16/59    7/17/69     7/18/69    7/19/91    7/20/49     7/31/60    7/22/66    7/2.1/19    7/24A9     7/23/00     7/26/111   7/27/09     7/la/49    7/29/69     7/30/89    7/31/89     a/l/st      6/2/80     4/3/6#      4/4/6
                                120                                                                                                                                                                                               VIM           ------


                                110

                    11-N




                    E           go

                                so


                    rY          70


                    7           60
                    u
                    ul
                                30



                                40

                    ui
                    ry          30

                    V)          20


                                0
                                                                                                             ............................................
                                                                                                                                                                                        ...........................................................
                                                                                                                                                                                                                   (13asenow)
                                0
                                0         24         46         72                    1"          144        168         192        216        240         244         zoo        all        334         360        304         408        432         45$        480
                                                                                                                                                                    TIME (HOURS)




                                FIGURE 16.                               Myakka River at S.R. 780 (B130) - Storm 1.

                                                                                                                                                                          58














                             1/22/69   1/23/91    2/24/19    0/26/49   1/26/46    1/27/49    fp/n/80    0/2t/st   0/30/st    10/l/u     10/2/69    10/3/59    10/4/99   10/5/61    1010A9     10/7/80    10/b/89    10/9/69   lotiolge   10111A9    10/1-2/8.0




               rn
                 E



               Clf

                 r
               u
               co
               Es      30



                       30


               (A



                       10
                                                                                                                                                                                               ------------
                                                                .......................................................................                                                                        ........
                       0
                          0         24        44        72         of        120        144        Ion        192        216       240        264        288        312        3M        360        364        406        432        436       460        504
                                                                                                                                                       TIME (HOURS)




                      FIGURE 17.                                Myakka River at S.R. 780 (B130)                                                                       Storm 2.

                                                                                                                                                          59









          was found by the comparison of rainfall (P) and direct runoff (R)
          A direct runoff volume (R) of 70.4 mm resulted from 103.1 mm of
          rainfall (P) yielding a total abstraction (F) of 33.0 mm, with only
          a 32 percent retention rate. This is considerably lower than the
          retention observed during storm 1.

                The peak rate factor (K), calculated to be 0.81, w   as slightly
          higher than the accepted SCS value of 0.75. This seems to be a
          function of a disproportionately long time to peak (103 hours).
          Otherwise, the SCS Unit Hydrograph model provides a good
          approximation of rainfall/runoff relations for this subbasin.

                The back-calculated curve number (CN) was found to be 89 which
          reasonably approximates composite values in the range suggested by
          SCS guidelines for areas of combined agriculture and idle lands.

                The upper portion of the watershed, which is wide, is capable
          of collecting large amounts of rainfall during dry conditions and
          is capable of providing storage in both surface depressions and
          within the sandy topsoil. During wet periods this storage capacity
          is diminished.

                The overall configuration of this watershed tends to dampen
          the effects of fluctuations in storage capacity. The lower portion
          of the watershed, which is narrow, presents much less catchment
          area.   Therefore, low initial flow rates are generated near the
          basin outlet and the time of concentration is increased.            The
          resultant effect is an increase in residence time and a more even
          rate of flow.



                Myakka River between Upper and Lower Lakes (B140)

                Gaging Station #2298830 is located on the main channel of the
          River at a point midway between Upper Lake Myakka and Lower Lake
          Myakka. The corresponding watershed includes all portions of the
          Myakka Basin upstream of the station as well as the Howard Creek
          subbasin, which drains into Upper Lake Myakka. The total surface
          area of the watershed is 59,313 ha. Potential surface retention
          areas include Tatum Sawgrass, Upper Lake Myakka, and numerous
          shallow depressional areas.

                The storm 1 hydrograph (Figure 18) was composed of a low,
          extremely wide feature with no distinguishable peak.        There was
          however a recognizable correlation between rainfall occurrence and
          variations in runof f rate. The rising limb of the curve was gently
          sloped as was the receding limb. This illustrates the moderating
          effect of Upper Lake Myakka on runoff from the watershed.

                Total rainfall (P) , based on monitoring stations in the Myakka
          State Park, was estimated to be 141.2 mm. of this amount, 125.3 mm
          was retained in the watershed for a total abstraction (F) of 89

                                            60























                           7/13/89   7/16/09   7/17/09   I/iS/09   7/19/0#    7/20/89   7/21/09   7/22/69   7/23/89    7/24/tt   7/23/89   7/3S/11    7/37/51   7/la/89   7/2#/Bl   7/30/69    7/31/69   6/l/89     8/2/60    0/3/69     6/4/69
                         2b

                         24

                         23

                         22

                         2t
               V)

                         is
               E'a

                         le

                         t5

                         t4
               <         13
               r         12
               u
               cn        11





               LLJ
               fy                                                                                      ............................................................................................................


                         3

                         2

                         1

                         0
                         0        24        46        72                  120       144        log       192       216       240        264       2"        312        336       360       394       408        432       436        "0        504
                                                                                                                                                TIME (HOURS)



                         FIGURE 18.                        Myakka River between Upper and Lower Lakes (B140) - Storm 1.



                                                                                                                                                     61









          percent. This rate of retention was comparable with rates observed
          in other subbasins during this storm.

               The storm 2 hydrograph (Figure 19) consisted of a single low,
          wide-based peak climaxed by a peak flow rate (qP) of 11.5 cms. The
          most notable feature of this curve was the extremely shallow slope
          of the receding limb produced by the retention capacity of Upper
          Lake Myakka.   The curve indicated no effects of inflow from the
          Howard Creek subbasin presumably because the creek drains into
          Upper Lake Myakka, thus blending smoothly with runoff from other
          areas of the watershed.

               Total rainfall (P) for this storm period was estimated to be
          102.4 mm. The total abstraction (F) retained by the watershed was
          found to be 86 percent, or 87.6 mm. This high rate of abstraction
          was attributed to the presence of Upper Lake Myakka as well as the
          numerous depressional areas within the watershed.

               The peak rate factor (K) was calculated to be 0.73 which
          closely approximates the accepted SCS value of 0.75. Based on this
          observation, the SCS unit hydrograph model should be adequate to
          describe and predict rainfall/runoff behavior of this subbasin.

               The subbasin curve number (CN) was back-calculated to be 74.
          This falls in the middle of the range of values (61 to 86) given by
          SCS guidelines for watersheds containing the soil type and land use
          found in this subbasin.

               The combined features of abundant surface storage and a
          relatively narrow downstream configuration create a dramatic
          moderating effect on flow rate.    Because of this, variations in
          soil moisture content have minimal effect on residence time. This
          effect extends to inflow from Howard Creek.



               Myakka River at control near Laurel (B160)

               Gaging Station #2298880 is located 153 m downstream of the
          Lower Lake Myakka control structure. The watershed includes all
          previously described subbasins as well as an additional area of
          6,216 ha (including Lower Lake Myakka) for a total surface area of
          65,529 ha. The presence of the control structure makes analysis by
          SCS methods impractical.        Therefore, only rainfall-runoff
          comparisons were performed.

               The storm I hydrograph (Figure 20) was composed of a major
          peaking feature that contained several smaller peaks, a pronounced
          climactic peak, and a receding limb interrupted by a vertical
          increase in flow rate. The smaller peaks roughly correlated with
          rainfall events, while the major feature illustrates the moderating
          effect of the control structure.



                                          62




























                        24

                        23

                        22

                        21

                        20

                        to



                        17



                        is

                        14
              <         13
              r         U
              u
              (A        11
                        10








                                                            ..............................................................................................................................................
              (A        4                                                                                                                                   (Boseflow)

                        3

                        2



                        0
                                  24        48        72                   120        144       isil       102        all       240        254       264        312        339       360        3"         40        433        434       4W         504
                                                                                                                                                   TIME (HOURS)



                        FIGURE 19.                            Myakka, River between Upper and Lower Lakes (B140) - Storm 2.

                                                                                                                                                       63



















                                    7A318t     7/16/69    7/17/80    7/la/80     7/19/112   7/20/99     7/21/49    7/22/tg    1/73/09    7/24/69    7/23/89     7/20/19    7/27/gg    7/18/to     7/30/60     7/30/89   7/31/09     $/'/to      6/2/to     8/3/8f     4/4
                               33                                                                                                                                                                                                                                    --
                                                                                                                                                                                                               .. ....... .
                                                                   12-                                                                                                                                         . ... .... ...
                               34                                                                                                               Nf
                               33

                               32

                               31



                               29



                               27

                               24

                               23
                     Cj@       24

                               23

                               22

                               21

                               20
                               to                      "I
                               is

                               17

                     CY-

                     (A        14

                               13

                               11                                                                                        ......................................................................................................
                               it                                                                                                                                                                                          (Baseflow)

                               to
                                  0         24         48         n                     920         144        1"         tol        210         240        264        2"         312         sm         340          3"        4"         Q2          4M         40
                                                                                                                                                                     TIME (HOURS)




                             FIGURE 2 0.                                Myakka River at control near Laurel (B160)                                                                                                     Storm 1.

                                                                                                                                                                        64










              Total rainfall (P) was estimated to be 115.3 mm, based on data
         obtained at monitoring stations located in Myakka River State Park.
         Direct runoff (R) amounted to 19.6 mm after an abstraction (F) of
         95.7 mm had been retained by the watershed. This yields retention
         rate of 83 percent which is in keeping with those of the other sub-
         basins during this storm.

              The storm 2 hydrograph (Figure 21) follows the same major
         trend as the storm 1 hydrograph, with a multi-peaked rising limb
         and a climactic peak.    Because of a lack of discharge data for
         October 3 through October 7, only a rough estimation of direct
         runoff (R) could be made. Using the available data, direct runoff
         (R) was estimated to be 21.8 mm. When this was compared to the
         total rainfall (P), an abstraction (F) of 19.6 was obtained. This
         indicates that 80 percent of the rainfall was retained in the
         watershed.

              Due to the presence of the control structure, more detailed
         observation and analysis is necessary to fully develop a predictive
         capability for this subbasin. However,, the general characteristics
         of rainfall/runoff relations seem to indicate that this portion of
         the Myakka subbasin is an excellent moderator of flow rate for the
         remainder of the subbasin upstream.


              Howard Creek (B120)

              Gaging station #228760 is located on Howard Creek approxi-
         mately 1.5 km upstream of Upper Lake Myakka.      The Howard Creek
         watershed, with a surface area of 5180 ha, is the smallest subbasin
         treated in this study. The creek drains a rather narrow area along
         its length. There are few distinct branches from the main creek
         channel in the lower portion of the drainage area while the upper
         portion of the basin has overland connection with the creek. There
         are areas of sparse development in the upper reaches of the
         watershed and a small number of depressional wet areas scattered
         throughout.

              For three and a half months prior to storm 1, the Howard Creek
         gaging station recorded zero flow rates with the exception of the
         first seven days of July. Therefore, extremely low antecedent soil
         moisture conditions greatly influenced the shape of the storm 1
         hydrograph (Figure 22). A minimal base flow rate of 40.6 mm was
         created by rainfall which began on July 18 and continued through
         July 27. During this period a total of 181.9 mm of rain fell, as
         estimated from records of the monitoring station located at the
         north entrance of the Myakka River State Park.     of this amount,
         179.4 mm was retained by the watershed to yield a 99 percent
         abstraction rate.

              The storm 2 hydrograph (Figure 23  contrasted sharply with the
         storm 1 hydrograph. Frequent rainfall had occurred prior to the

                                          65





















                                1/21/119                                                                                                                          W/4/99     10/5/02    s0/a/12   10/7/89    10/6/81    10/11/110  10/w/ae    w/ii/btp   10/12/0
                              30
                              29                                                                                                                                                                 OEM

                              26

                              27

                              26

                              23

                              24
                   E          23
                   @,.,o      22

                              21

                              20
                   (Y         it
                   <          is

                              17

                              Is

                              13
                              :4
                   <          3
                              12
                   w
                              11

                              10
                                                                  ......................................               .....................................................................................................







                              0        24         48                              120        144        111        102        210        240       2114       2"         sit        3M         360        364        400        432        4M         "a
                                                                                                                                                            TIME (HOURS)




                              FIGURE 21.                                 Myakka River at control near Laurel (B160) - Storm 2.

                                                                                                                                                                  66


























                           7/15/at     7/10/19   7/1 Y/ag   7/18/59    7/19/09    7/20/00    7/31/81    7/21/1,    7/23/,,    7/24/82     7/23/60    7/26/69    7/27/49    7/28/89    7/29/69    7/30/as     7/31/so    4/1/69      6/2/80     6/3/89     6/4/09
                      2.3

                      2.4

                      2.3

                      L2
              W       2.1

                      2.0
              E       1-9
                      1.8
              Ld      1.7
              (D      1.6
              O:f     1.5
              <       1.4

                      1.3

                      1.2



                      1.0

                      0.9
              < 0.6

                      0.7

                      0.6

                      0.3

                      0,4

                      0.3

                      IL2

                      0.1

                      0.0
                          a        24         48         72                   120        144        is$        192         210        240        26.        2"         312         uG        360         364        406        432        436         eo         30'
                                                                                                                                                          TIME (HOURS)



                      FIGURE 22.                                 Howard Creek (B120) - Storm 1.

                                                                                                                                                               67

























                             1/72/09  1/23/69   0/24/69  9/25/69   9/26/69  0/27/49   I/U/46    0/24/59  1/30/69   IQ/1/59   10/l/se  10/3/40   10/4/49   10/5/69  10/4/69   10/7AO    10/2/86  10/s/es   10/10/59  10/11/80 10/12
                                                       is
                        L4

                        L3


                 V)     2.1

                        LO
                 E      1-1
                        1.6

                        1.7

                        1.6

                        1.5
                 <      1.4

                        1.3

                        1.2

                        1.1

                        1.0

                        0.1
                 <      0.4


                        0,4

                        0.5

                        0.4

                        0.3

                        0,2
                        0.1                   ..............................................                                                                                                    - - - - - - - - - - -
                                                                                                                                                 .............................
                        0.0
                           0                  44       72       of       120       144       Is$       192      216       240      n4        28i       312      336                364       400       432       4N       4W
                                                                                                                                           TIME        (HOURS)




                        FIGURE 23.                           Howard Creek (B120)                                         Storm 2.

                                                                                                                                               68









         second study period, thereby increasing the soil moisture content
         in the watershed. This was evident by the shape of the single peak
         of the hydrograph which rose almost vertically reaching a peak flow
         (q ) of 2.4 cms within 39 hours. The receding limb of the curve
         foilowed a much more gentle slope, returning to the preceding base
         flow of 0.1 cms after a period of 11 days.

              The peak rate factor (K) was calculated to be 0.29 which was
         well below the standard SCS value of 0.75. This can be directly
         attributed to the short time to peak (Tp). Based on this finding,
         extreme care should be exercised in applying' SCS methods of
         rainfall/runoff prediction to this subbasin.

              A curve number (CN) of 76 was back-calculated from pertinent
         event specific data, which agrees with those set forth in SCS
         guidelines.

              The analysis of this subbasin suggests that the most critical
         factor in the determination of rainfall/runoff relations is the
         antecedent soil moisture condition. The two hydrographs represent
         extreme ends of the spectrum of soil moisture content and indicate
         that substantial fluctuations in flow conditions can occur in short
         time periods.


              Deer Prairie Slough (B170)

              Gaging Station #2299160 is located on Deer Prairie Creek, 1.6
         km north of Interstate 75. This subbasin contains a surface area
         of 9,583 ha.   The watershed is elongated along the axis of the
         creek and adjoining slough.   The upper reaches of the watershed
         contain numerous surface-isolated depressional features and areas
         of swampland.

              Storm 1 was preceded by two months of zero flow, or in some
         cases minimal flow.    Rainfall began on July 22 and continued
         sporadically through August 1. The curve depicted on the storm 1
         hydrograph (Figure 24) is based on an incomplete data set.
         Streamflow data prior to July 28 was not available for this gaging
         station. Examination of this curve shows that the flow rate rises
         rapidly in response to rainfall events, and then quickly
         diminishes. This is attributed to the presence of channelization
         of the lower one quarter of the watershed which quickly passed
         runoff from that area through the gaging station.      It was also
         noted that the return to base flow requires an extended period of
         time due to the lack of channelization in the upper reaches of the
         watershed.

              A total of 130.6 mm of rain fell during the study period of
         which 5.3 mm was passed out of the watershed as direct runoff (R).
         Thus, 125.3 mm or 96 percent of the rainfall was retained.


                                         69



















                              7/13/69   7/16/90    7/17/69    7/16/80   7/11/69    7/30/49   7/21/00    7/12/59   7/23/81    7/24AJ    7/33/89    7/26/59. 7/27/91     7/20/99    7/29/89   7130181    7/31/60    AA189      6/2/60     6/3/89    4/4/69
                              2..

                              L#

                              2.3

                              2.2

                              It
                  Lo          2.0

                  rn
                  E

                  Ld          1.6

                              1.4
                  <           1.3

                              1.2

                  V)          1.1
                              1.0

                              Ms

                              0.8
                  <           0.7
                  w
                              0.9

                              0.5
                  V)          14

                              0.3

                              0.2

                              W
                                                                                                                                                                                                                                        (Bosenow)
                              0       24         46        72         of        120       144        164       192        214        240       264        2U        312        336        360        364       406        432       456        460
                                                                                                                                                        TIME (HOURS)



                              FIGURE 24.                            Deer Prairie Slough (B170)                                                            Storm 1.
                                                                                                                                                                            1@@

                                                                                                                                                             70










              The storm 2 hydrograph (Figure 25) consisted of a single peak
        on the rising limb, which was nearly vertical. A peak flow (qP) of
        1. 4 cms occurred after a time to peak (Tp) of 52 hours.           The
        receding limb of the curve was marked by several fluctuations
        having no correlation to the rainfall pattern.          This may be
        attributed to variations in the flow pattern of the creek brought
        about by uneven distributions of rainfall within the subbasin . A
        peak rate factor (K) of 3.83 was calculated for this hydrograph
        which rendered comparison to the standard SCS value of 0.75
        useless.    The extreme quickness with which flow rate increased
        bears no resemblance to the SCS prediction of runoff behavior.

              A subbasin curve number (CN) of 76 was back-calculated which
        reasonably approximates the accepted SCS value for the type of soil
        cover and land use found in this area.

              The extremely short times required to reach peak flow within
        this subbasin render the standard SCS hydrograph ineffective in
        predicting runoff behavior. This subbasin can be divided into two
        distinct sections based on retention characteristics. The lower
        one quarter is highly channelized, thus residence time is minimal
        in this area. The remainder of the area tends to retain runoff in
        depressional and marshy surface storage releasing runoff in a
        steady low flow.      Therefore, it is believed that a further
        breakdown of this subbasin for study would permit a more reliable
        prediction of the characteristic rainfall/runoff response.


              Big Slough Canal at S.R. 72 (BISO)

              Gaging Station #2299410 is located on the upper reach of Big
        Slough Canal at the State Road 72 bridge.             This subbasin
        encompasses an area of 9,583 ha in which at least six flowing wells
        are located. The watershed is drained by numerous streams, both
        ditched and natural, and contains several depressional surface
        features.

              The storm 1 hydrograph (Figure 26) consisted of two major
        peaking features within which several small peaks appear, roughly
        corresponding to the pattern of rainfall that occurred during the
        study period.     Because of these smaller features, a reliable
        analogy to the SCS hydrograph was impractical.

              Total rainfall (P) during this storm period was estimated to
        be 89.4 mm, based on records of monitoring stations in the Myakka
        River State Park.    Direct runoff (R), as indicated by the storm
        hydrograph, was 11.8 mm, yielding a total abstraction (F) of 77.6
        mm. Thus, 87 percent of the excess rainfall (P) was retained in
        the watershed.

              The storm 2 hydrograph (Figure 27) was single-peaked with a
        peak flow of 1.4 cms. A span of 138 hours elapsed before flow

                                          71


















                              Z5 1/22/89 0/23/96  8134A#   9/26/46   I/n/59    1/37/49  #/U/49    9/21/90  8/30/10   10/1/49   10/2/90   10/3/tt  10/4/99   10/3/62   10/4/69                     10/9/59   10/10/69  10AIAS 10/1

                              L4
                              2.3               ME
                              2.2

                              2.1

                              2.0

                              to
                   E          1-8
                              1.7

                              1.4

                              1.3

                              1.4
                   <          1-3
                   r
                   U          1.2
                              1.1

                              1.0

                              0.



                              0.7

                              0.6

                              0.5



                              0.3


                              0.1                  ....................................        .....................................................                     .......................


                              0       24       44                          120       144       Is$       192      216       240      264       26d       312       3a       zoo       U4       40        432       456       4W
                                                                                                                                             TIME (HOURS)




                        FIGURE 25.                            Deer Prairie Slough (B170) - Storm 2.

                                                                                                                                               72























                         1/15/al    7/14/89    1/1 IAO    ?/'a/&'    7/19/80    7/20/89    7/21/111               7/23/80    7/24/09    7/25/69    7/26/gl      1/21/69   7/20/1,    1/79/09    1/10/411   1/31/tt     4/i/se     &/?/at     0/3/29      6/4/02     0/5

                    2.4

                    2.3

                    L2

                    LI



                    1.9
            E 1-0
                    1,7

                    1.6


            Q1      1.4
            <       tj
            -r      1.2
            U
            CA      1-1
                    1.0

                    04


            LIJ     0.6
            ry

            (A      0.4

                    0.3
                    01                                                                                                                                                 ..................         ......   ...........................................
                                                                                      ....................................                ......................                                 (Boseflow)


                        0        24         45         72         Od         120        044        ISO        102         216        340        264        3"          312       334        360        364         406        432        436         440        504
                                                                                                                                                         TIME (HOURS)



                        FIGURE 26.                               Big Slough at S.R. 72 (B150) - Storm I.

                                                                                                                                                               73

























                                                         8/22/69           IM149              8/24/99            1/26/49            I/N/49             9/3?/49            1/241/49           8/22/611          9/30/49            10/1/111           1011/112           10/3/50            10/4/91           10/5/at            W/11/11$           10/7/99            00/11/49           to/11/of           10110/51           10/11169           10/121
                                                2.3                                                      1.-  Q0.                 gomip                                      -                                                                    -
                                                2.4

                                                L3



                                                2.1

                                                2.0

                                                1.11
                                    E           1-8
                                                1.7

                                                1.4


                                    rY          1.4
                                    <           1.3
                                    F           1.2


                                                1.0

                                                0.0

                                                0.8
                                    <           0.7

                                                0.6

                                                0.5
                                    (A



                                                0.2
                                                CL3


                                                                                                           .........................................                                                               .................................


                                                      0                14                 46                n                  66                120                144                 Isq!              192                me                 340               2"                 2111               312               3M                  "o                 3"                 -00               432                 436                4"
                                                                                                                                                                                                                                                                                 TIME (HOURS)



                                                FIGURE 27.                                                                Big Slough at S.R. 72 (B150) - Storm 2.

                                                                                                                                                                                                                                                                                         74









         peaked.   This extended time to peak (Tp) is indicative of the
         retention capacity of this subbasin.

              A total rainfall (P) of 83.6 mm was estimated for this period
         which produced a direct runoff (R) of 8.4 mm.         Thus, a total
         abstraction (F) of 75.2 mm was retained by the watershed.        This
         abstraction rate of 90 percent is nearly the same as that observed
         during the first storm. This indicates that antecedent moisture
         conditions, which varied between the two storms, have a minimal
         effect on the retention capacity of this subbasin.

              The calculated peak rate factor (K) of 0.86 for this
         hydrograph is somewhat higher than the SCS standard value of 0.75.
         This is a result of the extended time to peak (Tp) that elapsed
         during this storm period, and suggests that the effects of intense
         rainfall events would be moderated.

              A curve number (CN) of 77 was back-calculated for this
         subbasin. This value compares reasonably to the range of values
         suggested by SCS guidelines for this type of soil cover and land
         use.


              Despite the ditching present in this portion of the Big Slough
         canal drainage basin, a high rate of retention was observed during
         both storm events with little influence by antecedent moisture
         conditions.   This is due in part to the presence of the f lowing
         wells which tend to moderate soil moisture levels.

              Big Slough Canal at North Port (BI80)

              Gaging Station #2299455 is located on Big Slough Canal near
         North Port.    This watershed has a total area of 24,088 ha and
         encompasses the entire Big Slough Canal drainage basin, including
         the area of Big Slough Canal described previously. Flowing wells
         are present throughout this watershed, many of which are drained by
         ditches.

              The storm 1 hydrograph (Figure 28) was composed of a series of
         three peaks, two of which were similar in shape. The shape of the
         curve generally correlates with rainfall events of the study
         period.

              Total rainfall (P) for this period was estimated to be 104.9
         mm, with a resulting direct runoff (R) of 8.5 mm. This yielded a
         92 percent retention with a total abstraction (F) of 96.4 mm.

              The storm 2 hydrograph (Figure 29) was single-peaked with a
         peak flow rate (P) of 3.4 cms. The rising limb of the curve was
         nearly vertical, with a time to peak (Tp) of 30 hours.            The
         receding limb began with a rapid decline but reached a more gentle
         slope approximately 24 hours after the peak flow (q   P) occurred.

                                          75


















                                7/15/al   7/16/59   7/1 ?/a 9  7/18/59    1/19/82   7/30/41   7/21/80    7/22/61   7/23/69    7/21/69   7/25/ag   7/24/09    7/27/09    I/la/61   7/21/89    7/30/89   7/31                  6/1/69    6/3/s,









                  Ld
                  CD        3.0
                  ry


                  7


                  C/')
                            Lo





                  LLJ
                  cr-
                            1.0




                                                                                                                                                                                                                               ..................
                                                                                                                                                                                                    easef low


                              0        24        46         72                  120        ...       Is$        192       M          3"        ft.        "I        pi        M          340       36.        408        432       436        480
                                                                                                                                                       TIME (HOURS)



                         FIGURE 28.                                Big Slough at North Port (B180)                                                                    Storm 1.

                                                                                                                                                           76



















                              0 0/22/99      0/13/49     0/24/110    1/25/90      I/n/"       9/27/89     0/26/89     1/21/49      9/30/60      10/1/90     10/l/90     10/3/60      tC/4/49     10/3/69     lo/,/,,      10PAD       10AAD       10/t/90     10/10/89     10/11AD     10/12/89





                            co


                  E

                  Li
                  0         10
                  Q@













                  cn


                                                     . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .




                               0          24          48          72                      120         1.4          Us          192          1w          W                                                3"           360         364         406          432         436,        4W           so
                                                                                                                                                                              TIME           (HOURS)



                       FIGURE 29.                                      Big Slough at North Port (B180) -                                                                                     Storm 2.

                                                                                                                                                                               77








                Total rainfall for this period was estimated to be 81.8 mm.
          Direct runoff (R), based on estimations from the hydrograph, was
          found to be 7.4 mm, with a total abstraction of 74.4 mm, yielding
          a retention of 91 percent.

                The peak f low f actor (K) for this hydrograph was calculated to
          be 0.21. This value is considerably lower than the SCS standard
          value of 0.75   primarily because of the short time to peak (Tp) .
          Therefore, the SCS unit hydrograph would not provide a reliable
          model for this  subbasin.

                The curve number (CN) for this watershed was back-calculated
          to be 77 which  falls within the range of 61 to 86 suggested by SCS
          guidelines for  the soil type and land use found in this subbasin.

                The effects of the ditching present in the lower portions of
          this subbasin are evident in the shape of the storm 2 hydrograph
          The ditching allows f low to peak and recede rapidly. These initiai
          rapid fluctuations are followed by a more even passage of runoff
          from the upper reaches of the watershed which is impeded somewhat
          by the absence of intense ditching.

          River and Tributary Water Chemistry Results

                Physical summary

                A summary of physical data for basin stations is contained in
          Appendix C. Seasonal variations in water temperature, with maximum
          values of around 30-320C, were similar for stations B140 through
          B180 (Figure 30). Stations B110-B130 had maximum water temperature
          of less than 300C. Maximum temperatures at all stations occurred
          between May and September.      pH varied f rom about 6 (with one
          exception of 5.69 at Station B140 during August) to about 9 (Figure
          31). The highest pH values were observed at Station B180. Lowest
          pH was observed at all stations during high discharge (June-
          September) as a result of increased organic acids flushed from the
          watershed.

                Conductivity values ranged from 128 to 1090 umhos (Figure 32).
          Conductivity values for sites on the Myakka River (ie. B110, B130    '
          B140 and B160) were below 610 umhos for the entire sampling period.
          Conductivity was generally the highest at stations B150 and B180
          (ie. Big Slough).    Lowest conductivity values were found during
          periods of high discharge.

                Dissolved oxygen values ranged from 0.05 to 15.40 mg/l (Table
          P). Thirty-one percent of all dissolved oxygen values fell below
          5.00 mg/l. Lowest values were generally found in July, August and
          September (Figure 33). over half of all dissolved oxygen values for
          sites B130 (80%) and B140 (53%) were below 5.00 mg/l, while no
          values below 5.00 mg/l were found at site B150. Saturation values


                                           78









                                                        Temperature (C)                                                Temperature (C)



                                     01-18     -                                                   01-18      -
                                     02-06     -                                                   02-06      -
                                     02-27     -                                                   02-27      -
                            rn
                            M        03-13     -                                                   03-13      -
                            IV
                                     04-10     -                                                   04-10      -

                                     05-01     -                                                   05-01      -
                                                                                                   05-30      -
                            H        05-30     -
                                     06-26     -                                                   06-26      -
                                     07-10     -                                                   07-10      -
                                     08-07     -                                                   08-07      -
                                     08-21     -                                                   08-21      -                    0
                            0        09-11     -                                                   09-11      -
                            0
                            H.       10-30     -                                                   10-30      -                  0
                                     11-13     -                                                   11-13      -                 0

                                     12-04     -                                                   12-04      - 0











                                                       Temperature (C)                                                Temperature (C)

                                                                               LA (A CIA                                                  I'a (A W CA
                                                              0"-P'Mwo"-P-                                                   0     4@ 0 co 0        4


                                     01-18     -           30.1            04 .10                  01-18      -
                                     02-06     -          'I               w w w tx                02-06      -                                rM to
                                                                           @- 1.- 0- I-w                                                       B." $--
                                                                           M OP. CA                02-27      -          4"                    co CA
                                     02-27 -             43       1        0 0 0                                                               00
                                     03-13     -                v                                  03-13      -                0.4
                                     04-10     -                     .14   0              P        04-10      -
                                                                                          w                                                              w
                                     05-01                          01334                 P-       05-01      -                  14                      P"
                                                                                          to                                                             CA
                                     05-30                                 0143           P        05-30      -
                                     06-26                             0   1040                    06-26      -
                                     07-10                                       43                07-10      -
                                                                                                   08-07      -                                          co
                                     08-07     -
                                     08-21     -                           *4 N                    08-21      -
                                     09-11                                                         09-11      -
                                     10-30                        4H                               10-30      -                  qq
                                     11-13     -                40                                 11-13      -                  W
                                     12-04     -    o<                                             12-04          0 .4











                                                                             pH                                                                           pH


                                                      Ln                 14       OD        co        0                            Ln       0)         li      co        CIO

                                                                                                                                                          ..........
                                          01-18       -                                                               01-18        -
                                          02-06       -                                                               02-06        -
                                          02-27       -                                                               02-27        -
                               m
                                          03-13                           0                                           03-13        -
                               0          04-10                                                                       04-10
                               lw         05-01                                                                       05-01        -                             0
                                          05-30                                                                       05-30        -
                                          06-26                                                                       06-26        -
                                          07-10                                                                       07-10        -                   0
                               rt         08-07                                                                       08-07        -           9
                               0          08-21                                                                       08-21        -               0
                                          09-11       -             9                                 -               09-11        -             0
                                          10-30       -                                               -               10-30        -                      9
                                          11-13       -                  0                            -               11-13
                                          12-04       -                                               -               12-04

                               rt

                               tor
                               ol
                      co       m




                               ct
                               m
                               w
                                                                              pH                                                                          pH


                                                      Ln       (M        -j       OD        co                                     Ln       (D                 ou        (D       0


                                          01-18       -                4 <130                                         01-18        -                  .1*
                                          02-06       -            40 4D                                              02-06        -                    .1
                                          02-27       -                0 0                                            02-27        -
                                          03-13       -          4.0           0                                      03-13        -              0
                                          04-10       -                *4                0                 p          04-10        -
                                          05-01       -               004                                             05-01        -                    0
                                                                                                           CA)                                                                          CA
                                          05-30       -              40 0                                             05-30        -                    0
                                          06-26       -           0140                                                06-26        -                  4
                                          07-10       -                                                               07-10        -
                                                                                                           6                                                                            t7i
                                          08-07       -                                                               08-07        -                                                    CD
                                                                                                           P6
                                          08-21       -           40      0                                           08-21        -               <0

                                          09-11       -                                                               09-11        -
                                                                                                           0                                                             .10
                                          10-30       -              .060                                             10-30        -
                                                                                      w w w tu                                                                           tij tu
                                          11-13       -                 -W            P- P-- " I-.- -                 11-13        -                      40             @-A I-
                                                                                      C) 1A. CJ $.-                                                                      CD CA
                                          12-04 -                         04    *1    0000-                           12-04









                                            Conductivity                                    Conductivity


                                                            0 0                         0 0 0      0   0    0  0
                                   0  0 0 0      0   0 0 0 0                     0  0 0 0 0        0   0    0  0


                           01-18                                          01-18  -          0
                           02-06                                          02-06  -
                           02-27                                          02-27  -          0
                           03-13                                          03-13 -
                     m     04-10                                          04-10 -
                     0
                     :5    05-01 -           0                            05-01 -
                     19                                                   05-30  -          0
                           05-30 -

                           06-26 -                                        06-26
                           07-10 -                                        07-10 -           0
                           08-07   -  0                                   08-07  -
                           08-21   -  0                                   08-21  -
                     0     09-11   -  0                                   09-11  -
                           10-30   -  0                                   10-30 -           0
                     :3    11-13 -                                        11-13  -
                     0     12-04   -  0                                   12-04 -       0
                     0






                CO


                                            Conductivity                                    Conductivity
                     rt                                                                            - - -
                     tr               "   4- 0) 00                                          0) 00  0   "       ;;    I
                                      0   0  0 0 0 0                                0   0   0  0   0   0   0   0
                     IV            0  0   0  0 0 0 0           0                 0  0   0   0
                     m

                           01-18 -    40  0                               01-18 -                 0
                                                                          02-06  -    0      0
                           02-06 -    @OD
                     m     02-27   -  41 OD                               02-27  -      0      0
                                                                   w
                                                                          03-13 -           00
                           03-13   -    w                          $.-
                           04-10 -        40 0                     9      04-10 -                  00
                                                                   w

                                                                   Ca
                                                                   p      05-30 -
                           05-01   -                               1.-    05-01  -                 *0
                           05-30   -      0"                       w
                           06-26   -      (044                            06-26  -          0    0
                                                                   &
                           07-10   -  0-04                                07-10  -            00
                           08-07   -  0                                   OB-07  -     00
                                                                   la.
                           08-21   -  0                            w      08-21  -          0
                                                                          09-11  -      00
                           09-11   -  41
                           io-30      40                 0414*            10-30 -           00          to w   -
                                                                                                        I- P@
                           11-13                                          11-13  -                      CO LA  -
                                                         M.P,C.01-                                      00
                           12-04      4D                                  12-04 -            OD








             TABLE P. Summary of             dissolved oxygen values at basin sites.

                                             B110                       B130                        B140

                       DATE          TIME    D.O.   SAT         TIME    D.O.   SAT          TIME    D.O.   SAT %       TIME

                    19890118         1055    7.93    85.6       1142    4.00    44.9        1229    4.70    49.7       1345
                    19890206         1020    6.75    76.6       1058    2.90    30.1        1143    5.20    61.3       1340
                    19890227         1029    9.90    94.1       1112    7.15    82.0        1228    9.40    97.4       1427
                    19890313         1005    9.30    99.4       1040    4.85    52.4        1124    7.20    80.1       1332
                    19890410         1044    7.50    86.0       1125    3.62    43.1        1205    7.50    91.0       1410
                    19890501         1024    9.55   111.6       1106    3.60    43.7        1144    5.00    62.3       1318
                    19890530          930    3.48    43.8       1016    2.45    31.4        1052    4.50    58.7       1224
                    19890626         1005    5.11    62.0       1101    6.65    83.6        1131    4.30    55.1       1322
                    19890710         1041    2.94    37.6       1125    0.71      9.3       1200    0.05      0.7      1358
                    19890807         1048    4.26    54.5       1122    1.60    21.2        1150    0.38      5.1      1316
                    19890821         1035    4.39    55.2       1110    1.63    20.9        1136    2.00    26.3       1307
                    19890911         1052    4.26    54.1       1128    2.62    34.2        1332    1.39    18.4       1457
                    19891030         1008    5.71    65.5       1049    2.42    27.8        1125    4.60    53.7       1323
                    19891113         1020    7.41    83.3       1050    4.48    50.3        1128    6.30    70.8       1254
                    19891204         1119   10.60   103.0       1149    7.70    76.5        1229    9.80   101.6       1358

                               MIN             2.9   37.6                 0.7     9.3                 0.1     0.7
                               MAX           10.6   111.6                 7.7   83.6                  9.8  101.6



                                             B120                       B170                        B150                     B

                                     TIME    D.O.   SAT         TIME    D.O.   SAT %        TIME    D.O.   SAT %       TIME

                    19890118          950    9.00    95.2       1640   11.80   132.6        1306    8.05    86.9       1710
                    19890206          908    8.39    92.5       1510   12.10   144.0        1238    8.10    94.6       1535
                    19890227          915    8.80    80.8       1630   11.70   123.8        1311    10.40  110.1       1706
                    19890313          911   10.40   112.3       1522    8.35    96.6        1156    8.35    93.8       1458
                    19890410          955    6.35    74.2       1612   11.00   148.4        1306    8.40   100.0       1550
                    19890501          940    5.10    61.3       1503    9.60   129.6        1217    7.10    87.8       1440
                    19890530                                                                1128    6.31    78.0       1425
                    19890626                                    1501    6.92    87.0        1203    6.60    84.5       1438-
                    19890710          944    8.15   106.3       1550    7.20    98.9        1233    6.83    91.3       1528
                    19890807          956    3.83    50.3       1504    5.98    82.1        1220    5.39    70.8       1446
                    19890821          947    1.64    19.2       2109    4.75    63.0        1209    5.77    75.2       2042
                    19890911          949    0.24      3.1      1719    6.20    83.7        1400    7.01    91.4       i658
                    19891030          910    6.06    69.5       1525    7.99    93.3        1153    8.20    94.9       1504
                    19891113          923    9.25   103.9       1506    7.58    88.6        1154    8.23    94.4       1445
                    19891204         1024    12.80  119.0       1545   10.00   101.5        1258    11.80  113.4       1527

                               MIN             0.2     3.1                4.8   63.0                  5.4   70.8
                               MAX           12.8   119.0               12.1   148.4                11.8   113.4


                                                                                82







                                          DO (mg/1)                                        DO (mg1l)
                                 0         m    -  i@a' :@ 1@ -
                                              w 0

                                                         r--T-
                         01-18
                         02:-06                                        01-18
                         02-27                                         02-06
                         03-13                                         02-27
                                                                       03-13    -              0
                   0     04-10   -                0                    04-10    -          0
                         05-01   -             0                       05-01            0
                         05-30   -                                     05-30
                         06-26   -
                                                                       06-26
                         07-10   -            0                                                                01
                                                                       07-10                0
                         08-07   -         0                           08-07    -    0
                   rr    08-21   -                                     08-21    -  0
                   0     09-11   -                                     09-11    -P
                         10-30   -            0                        10-30    -          0
                         11-13   -            0
                         12-04   -                                     11-13    -
                                                                       12-  04                     0


                   m
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                                              II II II I I .           01-18    -   10      41
                         0-1-18  -    <9      0                        02-06    -           <0
                         02-06   -  -1 410                                          mw
                                                                m      0 24 - 2 7   1-.- P-    0
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                         03-13   -      4     4                        04-10                0                  co
                         04-10   -    @l      41 0              co
                         05-01   -    114     00                L4     05-01                                   cn
                                                                p      05-30               0          11
                                                                       06-26               oll
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                         06-26         40 KI                           07-10    -          01                  CL
                         07-10   -1000                          0                                              co
                         08-07   -4CB 0                         >      08-07    -      10                      co
                                                  114-10        z      08-21    -       110
                         08-21   - AOO                          0
                         09-11   -4EI 0           w w wtz       w      09-11    -          <30
                                                  " I-- @-- ?-1        10-30    -           01
                         10-30   -  -0 4* 0       m 00. C#) $"
                         11-13   -     11 40      0000      1   0      11-13    -           0 .0
                                                                       12-04    -                0 <1
                         12-04   -            11 46









          below 10% were found at B120, B130 and B140 (Table P)         Super-
          saturation values were found at all sites except B130.         These
          values suggest that night-time dissolved oxygen values may fall to
          extremely low values, with the possibility of anoxic conditions.
          Supersaturated values were most common during periods of low
          discharge.
          PO   Of the dissolved species analyzed (i.e., DOC, NH4, N03+NO2 @nd
            4) all but nitrate + nitrite exhibited a seasonal variation
          (Appendix C and D).   For all sampling stations, DOC had maximum
          concentrations during high runoff. The other di'ssolved nutrients
          with the exception of nitrate and nitrite exhibited highest
          concentrations generally during high discharge also, but the
          pattern was not as consistent as that observed with DOC. This is
          clearly reflected in the rating curve analyses discussed below.

               Particulate carbon, nitrogen and phosphorus showed no relation
          to runoff. The particulate carbon and nitrogen data from the last
          half of the study, however, have not been evaluated.

               Total suspended solid concentrations (TSS) varied erratically
          during the study period at most stations. Highest suspended solid
          concentrations often occurred during high discharge, but this was
          not the rule.



               Annual Nutrient Loads

               The data on water chemistry collected at each station can be
          combined with discharge data to calculate annual fluxes or loads
          f rom the various subbasins of the Myakka watershed. The approaches
          to making such calculations were discussed above and the f irst
          involves the extrapolation of data using rating curves. of course,
          this approach assumes that statistically significant rating curves
          can be established.

               The establishment of rating curves was attempted using the
          data from seven stations for which water chemistry and discharge
          data were available.   Log-transformed data were used to regress
          concentration, C, on discharge, Q, assuming the following expected
          relationship:


                                   Log C = a+bLogQ



          where a and b are regression constants.

               The results of regression analyses of the data (Table Q)
          indicate that only dissolved organic carbon concentrations are
          significantly related to discharge. Dissolved phosphate is

                                          84









                        TABLE                     Rating curve parameters and statistics.


                                                               Station                                  a                        b                        ra                       P


                                                               Hilo                                0.751                    0.106                    0.733                     0.000
                                                               B120                                0.673                    0.177                    0.868                     0.000
                          Dissolved                            B140                                0.381                    0.1,10                   0.661                     0.000
                          Organic                              HIM                                 0.118                    0.2-58                   0.717                     0.000
                          Carbon                               B160                                0.134                    0.300                    0.787                     O.ODO
                                                               B 170                               0.750                    0.136                    0.865                     0.000
                                                               HIM                                 0.365                    0.138                    0.941                     0.000

                                                               8110                                -2.363                   0.117                    0.096                     0.141
                                                               B120                                -1.291                   -0.114                   0.127                     0.291
                          Dissolved                            B140                                -1.134                   -0.108                   0.012                     0.690
                          Nitrate                              11150                               1.670                    -U49                     0.176                     0.041
                          Nitrite                              B 160                               -0.505                   -0.297                   0.079                     0.230
                                                               B 170                               -1.525                   -0.012                   0,001                     0.916
                                                               11180                               -2.888                   0.342                    0.101                     0.213

                                                               13110                               -1.374                   -0.002                   0.000                     0.980
                                                               B 120                               -1.322                   0.044                    0,010                     0.736
                          Dissolved                            B140                                -5.111                   0.697                    0,615                     0.000
                          Anunortia                            B 150                               -0.052                   -0.317                   0.214                     0.020
                                                               B160                                -0.997                   -0.065                   0.002                     0,838
                                                               B 170                               -1.952                   0.048                    0.008                     0.712
                                                               11180                               -2.119                   0.106                    0.060                     0.285


                                                               Hilo                                -1.375                   0.152                    0.345                     0.002
                                                               B120                                -1.236                   0.231                    0.741                     0.000
                          Dissolved                            B140                                -3.474                   0.517                    0.719                     0.000
                          Phosphate                            B 150                               -2.081                   0.317                    0.527                     0.000
                                                               B 160                               -2.081                   0.392                    0.405                     0.001
                                                               B 170                               0.407                    -0325                    0601                      0.001
                                                               B180                                -0.369                   -0*.062                  0,067                     0.259

                                                               11110                               0.009                    0.012                    0.002                     0.656
                                                               8120                                0.690                    0.026                    0,003                     0.854
                          Total                                B140                                -2-248                   0.418                    0183                      0.009
                          Suspended                            H 150                               -0.662                   0.205                    0.230                     0.015
                          Solids                               B 160                               1.849                    -0.370                   0.114                     0.125
                                                               11170                               -0.116                   0.105                    0.085                     0.293
                                                               13180                               0.236                    0.051                    0.109                     0.347

                                                               11110                               -0.481                   -0.090                   0.067                     0.471
                                                               B120                                2.574                    -0.979                   0.846                     0.027
                          Particulate                          B140                                -2.168                   0.330                    0.396                     0.038
                          Organic                              B150                                -3.592                   0.754                    0.094                     0.333
                          Carbon                               B 160                               -1.745                   0.430                    0.087                     0.378
                                                               B 170                               -2-075                   0.446                    0.174                     0.410
                                                               B180                                -1.901                   0.301                    0.228                     0.279

                                                               11110                               -1.322                   -0.138                   0.065                     0.476
                                                               8120                                1.820                    -1.064                   0.868                     0.021
                          Particulate                          B 140                               -2.787                   0.271                    0,172                     0.205
                          Organic                              13150                               -2.179                   0.151                    0.002                     0.882
                          Nitrogen                             B 160                               -1.681                   0.174                    0.005                     0.840
                                                               B170                                -3.290                   0.475                    0,071                     0.610
                                                               8180                                -3.203                   0.389                    0.275                     0.227

                                                               Hilo                                -1.968                   -0.069                   0.036                     0.372
                                                               B 120                               -1.620                   0.129                    0.071                     0.338
                          Particulate                          B140                                -3.835                   0.330                    0.272                     0.011
                          Phosphorous                          DISO                                -2.482                   0.127                    0.066                     0.216
                                                               B160                                -1.396                   -0.1v                    0.011                     0.635
                                                               B 170                               -1.382                   -0.093                   0.033                     0.519
                                                               B180                                -3.021                   0.255                    0.361                     0.004








          significantly related to discharge for all but two stations. Very
          few additional significant relationships are observed between
          nutrient (or TSS) concentrations and discharge.

                Because of the general lack of significant relationships
          between nutrients and discharge, the extrapolation approach to
          assessing annual fluxes or loads does not appear appropriate.
          Nonetheless, this exercise is useful for the purpose of comparing
          subbasins.   For example, the rating curves for all stations are
          similar for DOC (i.e., all slopes of regression curves are
          positive), but results from most stations have n6gative slopes for
          regression curves relating dissolved nitrate + nitrite to discharge
          (Table Q). Negative slopes are sometimes indicative of constant
          inputs (e.g., from anthropogenic sources) the effects of which are
          diluted at high discharge.

               Given the availability data for concentrations and discharge,
          the best approach to estimating annual fluxes of nutrients is by
          interpolation. For this purpose, we used Method 5 shown in Table
          M.   Results yield the annual dissolved and particulate nutrient
          f luxes f or each station (Table R) .   These can be compared with
          subbasin area, discharge and other watershed characteristics to
          assess the relative efficiency of nutrient transport from each (to
          be done in later drafts).


          Estuarine Water Chemistry Results

               A summary of physical and chemical data for estuary stations
          is contained in Appendix E.       The results of the analyses of
          dissolved and particulate nutrients in estuarine samples are
          plotted against salinity in Appendix F.       Results f or the seven
          freshwater stations are plotted on the left part of each plot (left
          of zero salinity) in increasing order of station number from left
          to right. Comparing the freshwater concentrations of a substance
          to its concentrations at higher salinities provides a basis for
          judging estuarine behavior of the substance as discussed in the
          data reduction section. For this purpose, a line is subjectively
          drawn through the data for concentration versus salinity and
          interpreted as in Figure 9. The following discussion summarizes
          the behavior of the nutrients based on their estuarine
          distributions (some data are missing in this preliminary analysis) .

               Dissolved organic carbon is removed during estuarine transport
          from July through February. These are generally times of highest
          f luxes into the head of the estuary due to f reshwater runof f .
          Following these large inputs, much of the dissolved organic carbon
          must flocculate, forming particles. This is generally compatible
          with the observed particulate concentrations in the head waters of
          the estuary which are considerably enriched over freshwater levels.



                                           86








          TABLE R. Annual fluxes of dissolved and particulate nutrients (metric tons).




                                   ----------------- ft-.-.Dissolved --- - ------------------ - ------------------- Particulate ------------ ft--

              Station              Organic       Nitrate Ammonia Phosphate              Organic Organic        Phos- Total Susp.
                                    Carbon      + Nitrite                               Carbon      Nitrite phorous Solids



              13110                   5,900         5.8         13         98              9.9        1.3        1.3     310


              B120                      880         0.6           3        22              0.2        0.02       3.0     230


              B140                    5,000         5.7         22         79             59          7.6        3.5     500


              B150                     420          3.0         0.6          5             1.6        0.2        0.3       39


              B 160                      97         0.1         0.3          1             2.3        0.4        0.07      11


              B170                      570         0.5         0.4          1             0.8        0.2        0.4       67


              B180                    1,800         7.6         2. 1        14             3.6        0.5        1.6     230






                                                                       87








                In general, dissolved phosphate appears to follow DOC in its
          estuarine distribution.     Phosphate removal in the upper estuary
          appears to be matched by increased particulate phosphorous in the
          same region.

                Both dissolved nitrate-nitrite and ammonia have complex
          estuarine distributions.     In general, all species of dissolved
          nitrogen appear to be removed in the upper reaches of the estuary.
          Maxima at higher salinities suggest that some soluble nitrogen is
          released.

                Estuarine concentrations of total suspended. solids are
          generally greater than those in rivers. These concentrations are
          probably mostly due to resuspension of estuarine sediment and/or
          sediment transported into the estuary from the seaward end.
          Certainly some of the increased in suspended solids is also due to
          biogenic particle production.

          Sediment Chemistry Results

                Metals

                Results of sediment metal analyses are listed in Table S. The
          concentrations of seven trace metals (arsenic, cadmium, chromium,
          copper, lead, nickel, zinc, and mercury) were compared to the
          concentration of aluminum (FDER, 1988) to determine whether
          sediments were enriched with trace metals.         Results of these
          comparisons are shown in Figures 34 and 35.

                The sediments sampled in the Myakka River consisted largely of
          fine sand. Sands, because of their mineral composition and grain
          size, tend to have low metal concentrations.        This tendency is
          illustrated by the range of aluminum concentrations in Myakka River
          (370 to 1850). Concentrations of other metals were also low and
          fell within expected natural ranges (based on the metal:aluminum
          relationships).

                other sediments sampled in upper Charlotte Harbor were also
          predominately fine sand and had correspondingly low metal
          concentrations. Metal concentrations were within natural ranges.
          In the Peace River, the sediments had a greater proportion of fine-
          grained material, thus metal concentrations were higher than in the
          Myakka River and upper Charlotte Harbor. Metal concentrations were
          within natural ranges, however, with the exception of cadmium at
          station PER-2 which was slightly above the naturally expected
          range.

                Mercury cannot be evaluated by its relationship to aluminum.
          Nevertheless, in its statewide survey of metals in sediments from
          natural estuarine sites, FDER found that mercury concentrations did
          not exceed 0.21 (FDER, 1988).      Mercury concentrations from all
          stations in the Myakka River and upper Charlotte Harbor were less

                                            88







            TABLE S. Metal concentrations (ug g-1) in Myakka River, Peace River and Up
                               Harbor sediments.





                                          Aluminum a   Arsenic       Cadmium       Chromium      Copper         Iron        Lead        Nickel       Zinc
                       Station    Date    Mean  sd    Mean     sd   Mean    sd     Mean    sd   Mean sd     Mean   sd     Mean sd      Mean sd     Mean s


                       MYK-01  11/07/89   1850  354   0.940 0.085   0.210  0.014   6.30  1.70   0.94  0.08  1750    71   1.600 0.141   2.70  0.14  3.10  0.
                       MYK-02  11107189    370  127   1.000 _,.Ob   0.125  0.021   1.02  0.11   0.88  0.08   260    85   0.575 0.106   1.60  0.42  0.88  0.
                       MYK-03  11/07/89    630  212   1.100 0.14    0.155  0.007   2.35  1.48   1.05  0.07   765   290   0.775 0.163   2.25  0.78  0.91  0.
                       MYK-04  11/07/89   1030  382   1.150 0.07    0.130  0.014   1.80  0.99   1.03  0.10  1900      0  1.115 0.262   1.90  0.42  2.70  0.
                       PER-01  08/29/85   6133  404   2.567 0.75    0.323  0.021   13.67 1.15   4.00  0.35  3767   153   3.600 0.520   -1.0  -1.0  13.67 1.
                       PER-01  11/07/89   1900  707   0.960 0.33    0.155  0.021   4.40  1.98   0.71  0.11  1950   212   1.750 0.071   2.05  1.20  3.35  0.
                       PER-02  11/07/89  23000  5657  2.150 0.07    0.755  0.078   49.00  16.97 3.70  0.00  22500  2121  17.500 4.950  11.50 2.12  44.00 7.
                       PER-03  11/07/89   12500 707   2.650 0.21    0.145  0.035   23.50 3.54   1.80  0.28  9450   5020  10.150 1.202  2.70  0.00  26.50 0.
                       CHH-02  07/13/85   1333  208   0.507 0.05    0.067  0.006   4.70  0.56   0.75  0.06   797   136   1.833 0.252   -1.0  -1.0  2.83  0.
                       CHH-02  11/07/89   1400  141   0.930 0.09    0.220  0.085   3.65  0.64   1.05  0.07  1150    71   1.050 0.212   2.35  1.91  1.05  0.
                       CHH-07  09/24/86    320    99  0.205 0.00    0.010  0.000   1.05  0.07   0.66  0.01   150    42   0.300 0.042   1.85  0.21  1.05  0.
                       CHH-07  11/09/89    375  106   0.640 0.11    0.170  0.057   1.65  0.21   0.72  0.27   270    57   0.440 0.226   1.20  0.14  0.86  0.
                       CHH-19  11/08/89   2400  283   0.765 0.00    0.210  0.000   6.55  0.35   0.43  0.03  2800      0  1.850 0.071   1.85  1.06  3.40  0.
                       CHH-20  11/08/89   1025  247.  0.695 0.02    0.205  0.134   2.25  1.34   0.59  0.13  1070   325   -0.980 0.311  1.90  1.13  1.75  0.


                  a standard deviation.
                  b_1 = no data.
                   C-2 = below detection limit of 0.01 pg g-     Ifor mercury.






                                                                                              89












            a)                          Amenic/Aluminurn                                           b)                          Cadmium/Aluminum

               100                                                                                        1,                                                             P2



                                                                                                                   C7
               10                                                                                  E                                13  eM o                     P3
                                                                                                                   0     0       0      0.                       0
                                                                            3
                                                                            I    _M                   &I -:                         C2
                                                                                 Cr                                                 0
                            M2 OWS                      9
                           a          4C =2@0- C I I                                                                                --
                                        93 _ C2 0                                                 E
                         CiC7                                                                     U              C7
             0.1                                                                                      0.01,       a



                                                                     0000                                                      1000                         100M
                                          Aluminum (Ppm)                                                                            Aluminum (ppm)

               C)                       Chromium/Aluminum                                           d)                         CopW/Aluminurn

               100
                                                                                 C@2
                                                                                                         10-:
           E                                                                                        E
           CL                                                                                       CL                                                    Pj---           OF2
               10                                                                                   9L                                                            CF3
                                                                                                                                           Ml
                                                                                                                                           P1
                              7
                                                                                                                                                9





                                                                                                      0.1
                                                                     0000                                                     1 000                         lam
                                          Aluminum (Ppm)                                                                            Aluminum (Ppm)







                     FIGURE 34.                         Sediment concentrations of (a)                                                    arsenic,                 (b)
                                                        cadmium, (c) chromium and (d) copper.                                                              Points
                                                        within the two outer lines are considered to be
                                                        within the range for natural sediments (FDER,
                                                                                                                                                                  3
                                          C:2
                      513                  C
                            C           13 %12
                            7











                                                                                                                                    Mj; gC23 P,















                                                        1988).

                                                                                            90













     a)            Lead/Aluminum              b)            Nickel/Aluminum

      100



                                      an




                          Is
                                                            C60    9

           13



      0
                 1000                                      1000
                   Aluminum (ppm) "low                       Aluminum (POM) am




                         C)            Zinc/Aluminum




                                                            32
                                                       CF3

                          r= 10.
                          CL
                          CL

                                          C2 CIO

                            V        GM3




                                      100D          10000
                                        Aluminum (ppm)





         FIGURE 35.      sediment concentrations of (a) lead, (b) nickel and
                         c) zinc.   Points within the two outer lines are
                         considered to be within the range       for natural
                          19


                                                      C7
           3C@7












                                                       rj
                                                  C"



                                       C1C
                                        @2
                                      M@3













                         sediments (FDER, 1988).


                                          91








           that 0.21 ppm, indicating that mercury was within natural ranges
           At one station in the Peace River (PER-2) mercury slightly exceede@
           the 0.21 ppm guideline for natural sediments.

                Nutrients

                Concentrations of TOC, TKN, and TP in Myakka River sediments
           are listed in Table T.      Differences among stations in sediment
           nutrient concentrations appear to be due primarily to sediment
           grain size.    stations with the greatest nutrient concentrations
           were those that had the highest aluminum conCentrations, high
           aluminum being an indicator of fine-grained sediments.


           TABLE T. Nutrients (ug g-1) in Kyakka River, Peace River and Upper
                     Charlotte Harbor sediments.


                                       TOC              TEN            _TP


           STATION    DATE       MEAN        sd     BEAN   sd     MEAN      sd


           MYK-01    11/07/89    5550      354       420   57   700.0      84.0
           MYK-02    11/07/89    1900      566         66  35   760.0     905.0
           MYK-03    11/07/89    2900      707       265     7  120.0        0.0
           MYK-04    11/07/89    5350      212       365   21   760.0      42.4
           PER-01    08/29/85    9067     1137       550  145      0.6       0.1
           PER-01    11/07/89    8350     1061       405  120   825.0     162.6
           PER-02    11/07/89  77500      3536      3800  131   5400.0    1131.3
           PER-03    11/07/89  60500      2121      1900  283   3500.0    989.9
           CHH-02    07/13/85    3600     1735       129   38    -1. 0a    -1.0
           CHH-02    11/07/89    4800     1131       280   57   950.0      70.7
           CHH-07    09/24/86    1400      212       130   42    26.5        7.7
           CHH-07    02/10/87    1200      141       115     7   52.0      12.0
           CHH-07    05/05/87    3750      778       815  134   114.0      23.0
           CHH-07    12/10/87    5400      283       250   42    87.0      12.7
           CHH-07    11/09/89    1400      141       195   92   106.0      33.9
           CHH-19    11/08/89  17500       707      1150   71   565.0      63.6
           CHH-20    11/08/89  14500       707       810  141   520.0     282.8

                     a -1 = no data.


                Sediment nutrient concentrations in the Myakka River, Peace
           River, and upper Charlotte Harbor were compared to concentrations
           in natural sediments throughout Florida. Figure 36 shows TOC/TKN
           relationships from four statewide (Florida) surveys of sediment
           nutrients in 1986 - 1987, and, for comparison, TOC/TKN
           relationships for Myakka River and vicinity surf ace sediments.
           Data from the Myakka River area are plotted in the bottom of Figure
           36 along with the best fit lines from the September - December
           1986, January - March 1978 and November - December 1987 statewide


                                              92











                a)


                -10000
                0,                                                  J
                3                                                     ie

                                                     &
                E

                                                  4
                4)
                                                A

                   low-                           a      0
                z



                V



                                                       4A&"           1986
                                                       QQ0Q0Jn1-_-M`o@@9. 1987
                                                       0==    I -June. 1987
                                                       4066      Dec. 1987


                         1000                 10000                100000
                                   Total Organic Carbon (mg/kg)


                b)



                  10000 -


                                                                 ",,V 2
                E                                                 a

                                                                P3

                2
                   WOO                            0129


                              C7
                                  e
                                 %Plo E) C2          Florida:   Doe. 1986
                                                     Florida: !(3n@L - March. 1987
                    100                              Florida: Nov. - Dec. 1987
                                 M2             CC= Myokka RWr & vicinity. 1985, 1989
                         1000                 10000                ;00000
                                   Total Organic Carbon (mg/kg)


          FIGURE 36.      TOC and TIKK concentrations from (a) natural Florida
                          coastal sediments and (b) Myakka River, Peace River
                          and Upper Charlotte Harbor sediments.

                                            93









          data (from the top of the f igure)    TKN/TP relationships are shown
          similarly in Figure 37. Although not statistically rigorous, these
          comparisons provide a starting point for interpreting sediment
          nutrient concentrations.

               Concentrations of TOC and TKN and the TOC/TKN ratios for the
          Myakka River area are typical of those found during the statewide
          surveys. TP concentrations also fall within the range of values
          found during the statewide surveys but TP/TKN ratios tend to be
          higher than typical values found throughout the state. Phosphorus-
          bearing minerals are common in southwest Florida-and in the Myakka
          River watershed, so the higher TP/TKN ratios are probably related
          to regional geologic features.

               organics

               No organic compounds in excess of the detection limits listed
          in Table 0 were detected in the sediments of the Myakka River or
          nearby stations.

































                                            94











                              a)
                                  10 0 OWO

                                                                                                                a


                                                                                                                               10


                                    1000                                                                             A
                                                                   oa@ 0
                                  E
                                  4n                               0     too         00                     20
                                  2   100                                                              0
                                  0                                                  0
                                  Z
                                  CL

                                  0
                                  Mc                  a                          40
                                  a.



                                                                                                 ^^*A# Sept.        Dec., 1986
                                                                                                 Q90W Jan.         March, 1987
                                                                                                                   June. 1987
                                                                                                         Nov.      Dec. 1987


                                                100                                  1000
                                                             Total Kjeldahl          Nitrogen    (mg/kg)             '00'00

                              b)

                                  10000-
                                                                                                Pj          P2

                                                                   C2
                                   1000 - M2                     a
                                                                     13V             C2%C 19

                                  2  100-.                    C70 M3           -:::I-
                                  0
                                  -C
                                  CL

                                  0
                                  z
                                  a.
                                      10-

                                  1.2                                                        Florida: Sept.      Dec. 1986
                                                                                             Flori4o: Jain.     Wnch, 1987
                                                                                             Floridc: Nov.      Dec. 198 7
                                         1                                   P1      C11= Myokkos RKw           vicinity, 1985. 1989

                                                                                     1000                            10000
                                                             Total Kjeldchl Nitrogen (mq/kg)



                  FIGURE 37.                   TKN and TP concentrations from (a) natural Florida
                                               coastal sediments and (b) Myakka River, Peace River
                                               and Upper Charlotte Harbor sediments.

                                                                                 95











         VIII. Future Directions

              Report Synopsis

              The results presented in this report represent the first
         effort to summarize the information obtained during the first year
         of the Myakka River Basin Project. The emphasis for this report is
         on assessing water quality and hydrology of the basin study area.
         Information is available for the tidal portion of the river (ex.
         Estevez 1985, 1986) ; however, there is a paucity of information for
         the basin study. Therefore, it was most important to characterize
         the basin study area.

              An additional reason for focusing on the basin study area was
         that activities are occurring (e.g. phosphate mining activity,
         sludge spreading), or are planned (e.g. Walton Tract landfill,
         Carlton Reserve wellfield), for the basin that could possibly
         influence water quality functioning within the basin and estuary.
         The information obtained during the course of the study is
         therefore important from a planning perspective.       Finally, the
         information is needed for effective use of the Geographic
         Information System (GIS) that has been developed for the basin.

              Future Technical Reports

              Future reports will focus on an expansion of the analysis of
         data from basin stations, including analysis of data collected in
         1990, as well as an examination of long-term water quality and
         hydrological trends. In addition, a detailed assessment of data
         from the estuary stations will be made.

              Management Tools

              Several management tools for the Myakka River basin have been
         developed as part of this project. They include: a computer model;
         studies of the benthic and vegetative communities; a shoreline
         assessment and mapping project; and, a spatial ly-related database.
         Each of these provides information on important processes within
         the basin.

              The computer model is capable of duplicating the salinity
         distributions in the tidal portion of the river.          This one-
         dimensional hydrodynamic model can be used to predict changes in
         the salinity structure that may result from increases or decreases
         in freshwater input to the system. Activities in the basin that
         could result in such an increase include additional hardened
         surface in the watershed or input of treated wastewater via one or
         more of the Myakka's tributaries. Water withdrawal for public or
         private water supply could result in a decrease in input.

              Biological studies have established the current composition
         and condition of riverine communities.        The zonation schemes


                                          96









          suggested by the data can be used for goal-setting as well as a
          comparison with future data gathering efforts.

               The shoreline mapping and assessment project provides
          quantified data on the presence of hardened shorelines, wetlands,
          and exotic species along the river. These figures will provide the
          basis for measurable management goals.

               The database provides a platform for building the GIS, which
          will allow cumulative impacts on the system to be assessed. The
          management of natural resources has traditionally been accomplished
          through the permitting process. This process assesses each impact
          on a system individually, and tends to be species oriented and
          segmented in approach.   Such a system cannot address cumulative
          impacts and simply will not work across political boundaries. Five
          counties, a city, SWFWMD, plus various state and federal agencies
          have permitting responsibilities within the Myakka River basin. A
          holistic approach involving goal-setting for the entire watershed
          and adoption of ordinances basin-wide that recognize and support
          these goals is needed.       A watershed GIS can provide this
          perspective.

               Management Plan

               Development of a management plan for the entire watershed will
          involve, most importantly, establishing basin-wide goals. Many of
          these goals will result from work done as part of this project. As
          part of the plan development, we will identify pathways to attain
          the established goals and propose implementation strategies.






















                                          97













                                                   LITERATURE CITED





             APHA. 1985. Standard methods for the examination of water and wastewater, 16th edition.
                     American Public Health Association, Washington, D.C.

             Browder, J. 1987. An ecosystem view of management research in the Myakka River.

             Davis, J.S. and J. Zobrist. 1978. The interrelationships among chemi6al parameters in rivers -
                     analyzing the effect of natural and anthropogenic sources. Progress WaterTechnology 10: 65-
                     78.

             De Leuw, Cather and Brill. 1959. Engineering report on drainage canal connecting Myakka River
                     and Roberts Bay. Sarasota County, 25 p.

             Drummond, R. 1977. The Myakka River Basin, characteristics of a watershed. Senior Thesis, New
                     College.

             Dupraz, C., F. LeLong, J.P. Trop and B. Dumazet. 1982. Comparative study of the effects of
                     vegetation on the hydrological and hydrochemical flows in three minor catchments of Mount
                     Lozere (France) - methodological aspects and first results. Ln- Hydrological Research Basins
                     and Their Use in Water Resources Planning. Landeshydrologie, Berne, pp. 671-682.

             Estevez, E.D. 1985. A wet-season characterization of the tidal Myakka River. Draft, 295 p.

             Estevez, E.D. 1986. A dry-season characterization of the tidal Myakka River. Draft, 171 p.

             Estevez, E.D., C.A. Palmer, R.K. Evans and G.A. Blanchard. 1990. Shorelines of the Myakka River,
                     Sarasota and Charlotte Counties, Florida. Mote Marine Laboratory Technical Report Number
                     179, 15 p.

             FDER. 1988. A guide to the interpretation of metal concentrations in estuarine sediments. Coastal
                     Zone management Section, Florida Department of Environmental Regulation, Tallahassee,
                     Florida.

             Figueres, G., J.M. Martin, and M. Meybeck. 1978. Iron behavior in Zaine estuary. Netherlands J.
                     Sea Res. 12; 329-340.


             Foster, I.D.L. 1978a. Seasonal solute behaviour of stormflow in a small agricultural catchment.
                     Catena. 5:151-163.

             Foster, I.D.L. 1978b. A multivariate model of storm-period solute behaviour. Journal of Hydrology
                     39:339-353.

             Foster, I.D.L. 1980. Chemical yields in runoff and denudation in a small arable catchment, East
                     Devon, England. Journal of Hydrology 47:349-368.

             Hall, F.R. 1970. Dissolved solids-discharge relationships. 1: Mixing models. Water Resources
                     Research 6:845-850.



                                                              98









               Hammett, K.M. 1989. Physical processes, salinity characteristics and potential salinity changes due
                       to freshwater withdrawals in the tidal Myakka River, Florida. Draft USGS Report.

               Hammett, K.M., J.F. Turner, Jr. and W.R. Murphy, Jr. 1978. Magnitude and Frequency of Flooding
                       on the Myakka River, Southwest Florida. U.S. Geological Survey, Water Resources
                       Investigations 78-65, 40 p.

               Hand, J., V. Tauxe and J. Watts. 1988. 1988 Florida water quality assessment 305(b) Technical
                       Report, 235 p.

               Jansson, M. 1985. A comparison of detransformed logarithmic regres@ions and power function
                       regressions. Geografiska Annaler 67A:61-70.

               Joyner, B.F. and H. Sutcliffe, Jr. 1976. Water Resources of the Myakka River. U.S. Geological
                       Survey, Water Resources Investigations 76-58, 87 p.

               Kaul, L.W. and P.N. Froelich. 1984. Modeling estuarine nutrient geochemistry in a simple system.
                       Geochem. Cosmochim. Acta. 48:1417-1433.

               Li, Y. and L. Chan. 1979. Desorption of Ba and    226Ra from river-borne sediments in the Hudson
                       estuary. Earth Plant. Sci. Lett. 43:343-350.

               Lincer, J.L. (ed.). 1979. Myakka River workshop, Draft, 67 p.

               Miller, W.R. and R.H. Drever. 1977. Water chemistry of a stream following a storm, Absaroka
                       Mountains, Wyoming. Geological Society of America Bulletin 88:286-290.

               Milligan, M. 1990. Myakka River biological study: Down's Dam to Snook Haven. 200 p.

               Morris, J. and J. Miller. 1976. The Myakka River corridor. 115 p.

               Nilsson, B. 1971. Sediment transport i svenska vattendrag. Ett IHD-projekt. Del. 1, Methodik,
                       UNGI Rapport 4, Uppsala.

               Reid, J.M., D.A. MacLeod and M.S. Cresser. 1981. Factors affecting the chemistry of precipitation
                       and river water in an upland catchment. Journal of Hydrology 50:129-145.

               Rosenau, J.C., G.L. Faulkner, C.W. Handry, Jr. and R.W. Hull. 1977. Springs of Florida. Bureau of
                       Geology Bulletin No. 31, Florida Department of Natural Resources, Tallahassee, Florida.

               Soil Conservation Service. 1983. Soil Survey of Manatee County, Florida, 159 p.

               Soil Conservation Service. 1988. Soil Survey of Sarasota County, Florida. Draft Report.

               Turvey, N.D. 1975. Water quality in a tropical rain forested catchment. Journal of Hydrology
                       27:111-125.


               Walling, D.E. and I.D.L. Foster. 1978. The 1976 drought and nitrate levels in the River Exe Basin.
                       Journal of the Institution of Water Engineers and Scientists 32:341-352.

               Walling, D.E. and P. Kane. 1984. Suspended sediment properties and their geornorphological
                       significance. In: Catchment Experiments in Fluvial Geomorphology. T.P. Burt and D.E.

                                                               99










                     Walling, Editors. Geo Books, Norwich, pp. 311-334.

             Walling, D.E. and B.W. Webb. 1981. The reliability of suspended sediment load data. IAHS
                     Publication 133: 177-194.

             Walling, D.E. and B.W. Webb. 1983. The dissolved loads of rivers: A global overview. IAHS
                     Publication 141:3-20.


             Walling, D.E. and B.W. Webb. 1984. Local variation of nitrate levels in the Exe Basin, Devon, UK.
                     Beitrage Zur Hydologie 10:71 -100.

             Walling, D.E. and B.W. Webb. 1986a. Solutes in river systems. Ln. Solute Processes. S.T. Trudgill,
                     Editor. Wiley, Chichester, pp. 251-327.

             Walling, D.E. and W.B. Webb. 1986b. Suspended load in gravel bed rivers: UK experience. Lw.
                     Problems of Sediment Transport in Gravel-Bed Rivers. C.R. Thorne, R.D. Hey and J.C.
                     Bathurst, editors. Wiley, Chichester (in press).

             Webb, B.W. and D.E. Walling, 1983. Stream solute behaviour in the River Exe basin, Devon, UK.
                     IAHS Publication 414:153-169.

             Webb, B.W. and D.E. Walling. 1985. Nitrate behavior in streamflow from a grassland catchment in
                     Devon, U.K. Water Research 19:1005-1016.

             Winchester, B.H., J.S. Bays, J.C. Heguian and R.L. Knight. 1985. Physiography and vegetation
                     zonation of shallow emergent marshes in southwestern Florida. Wetlands 5:99-118.




























                                                            100




 I
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 I                    Basin and Estuary Station Descriptions
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             MYAM<A RXVE-.R FRESH H2 0 SAMI-LTNC@; POIN-rS

        Station                       Station Description
      Designation

         B110         Myakka City at bridge on State Rd 70
                      Sample at USGS Continuous Record Gaging Station
                      #02298608       27020'36"       82009'25"
                      Manatee Co.    Section 13 Township 36S     Range 21E

         B120         Howard Creek on Hi Hat Ranch approximately 4 mi.
                      south of State Rd. 780
                      Sample at USGS Continuous Record Gaging Station
                      #02298760       27017'17"       82020'25"
                      Sarasota Co. Section 6 Township 37S        Range 20E

         B130         Myakka River near Clay Gully inflow.     Sample from
                      bridge on Clay Gully Road.    North of Myakka River
                      State Park.
                      Sample at USGS Continuous Record Gaging Station
                      #02298700       27018'05"       82015'15"
                      Sarasota Co. Section 36 Township      36S Range 20E

         B140         Myakka River in the Myakka River State Park. 1/2
                      mile north of the State Road 72 entrance to the
                      State Park on the west bank of the river.
                      Sample at USGS Continuous Record Gaging Station
                      #02298830       27014'25"       82018'50"
                      Sarasota Co. Section 21 Township 37S Range 20E

         B150         Big Slough Canal at bridge on State Road 72 near
                      Myakka River State Park
                      Sample at USGS Continuous Record Gaging Station
                      #02299410       27011'35"       82008'40"
                      Sarasota Co. Section 6 Township 38S        Range 22E

         B155         Deer Prairie Slough at bridge on State Road 72.
                      Stage recorder to be installed by May 31, 1990.
                      Sarasota Co. Section 4 Township 38S        Range 21E

         B160         Myakka River on Chuck Down's property, 500ft
                      downstream from concrete dam.
                      Sample at USGS Continuous Record Gaging Station
                      #02298880       27011'07"       82021'21"
                      Sarasota Co. Section 12 Township 38S       Range 19E















         B165         Myakka River at bridge on Border Road.
                      Sample will be taken in the channel on the north
                      side of the bridge.
                      Correlate to USGS Continuous Record*Gaging Station
                      #02298880 (ie. B160)
                      Sarasota Co. Section 31 Township 38S      Range 19E

         B170         Deer Prairie Slough at bridge on 1-75. Sample will
                      be taken in the channel on the north side of the
                      bridge.
                      Correlate to USGS Continous Record Gaging Station
                      #02299160       27006'51"       82021'50"
                      Sarasota Co. Section 21 Township 39S      Range 21E

         B175         Deer Prairie Slough at the southern boundary of the
                      T. Mabry Carlton Jr. Memorial Reserve.
                      Stage recorder to be installed by May 31, 1990.
                      Sarasota Co.    Section 36 Township 38S Range 20E

         B180         Big Slough in North Port, 25 yards upstream from
                      1-75 bridge.
                      Sample at USGS Continous Record Gaging Station
                      #02299455       27006'30"       82012'20"
                      Sarasota Co. Section 9     Township 39S    Range 21E





















                  P4YAI<I<A RTVIER ]ESTUAIZIWE SrArrJEONS


         Station                               Station Description
       Designation

         E210         In Charlotte Harbor; 1.5 nautical miles SSE
                      (compass heading 140) of number 9 square green
                      channel marker at the Sarasota-Charlotte county
                      line; sample 25 yards west of the number 8
                      triangular red channel marker. Longitude W82:09:58;
                      Latitude N26:54:51. Loran Coordinates 14165.4
                      44080.0


         E220         In the Myakka River; 100 yards west of the El
                      Jobean Bridge (Highway 771) on the south side of
                      the channel; between the second and third canals in
                      the development on the south bank of the river; 75
                      yards south along the bisected railroad bridge.
                      Longitude W82:13:02 Latitude N26:57:22. Loran
                      Coordinates 14165.0 44122.1


         E230         In Myakka Bay; 50 yards north of hexagonal channel
                      marker B; line up between the canal on the west
                      bank and the large dead tree on the east bank.
                      Longitude W82:14:45 Latitude N26:59:00. Loran
                      Coordinates 14166.3 44143.2


         E240         In the Myakka River; 25 yards east of the dock with
                      a red bench; this dock is the first of three docks
                      south of statue (Myakka River God) on the south end
                      of   the   Tarpon   Point   development.     Longitude
                      W82:16:39 Latitude N27:00:83. Loran Coordinates
                      14166.8 44178.7


         E250         In the Myakka River; north of Big Slough mouth; on
                      the west side of the island off a trailer park; 200
                      yards south of the number 3 green square channel
                      marker; line up between the 2 headless palms on the
                      island to the east and just south of an area of low
                      mangroves on the west bank. Longitude W82:16:88
                      Latitude N27:01:98. Loran Coordinates 14168.5
                      44178.8















             E260         On the Myakka River; north of the highway 41 bridge
                          and Becky's Bait Bucket; 50 yards north of the
                          mouth of Deer Prairie Creek 25 feet from the tip of
                          the island with 3 palm trees;. sample in mid-
                          channel. Longitude W82:17:77 Latitude N27:03:03.
                          Loran Coordinates 14169.2 44191.8


             E270         On the Myakka River; upstream of the last mangrove;
                          after a bend with a single Australian pine; sample
                          in midstream at the first palm which hangs out over
                          the water; channel markers number 8 red triangular
                          and number 9 green square are 500 yards upstream.
                          Longitude W82:18:86 Latitude N27:03:94. Loran
                          Coordinates 14169.1 44205.7

             E280         On the Myakka River; three left bends in the river
                          followed by three right bends upstream of Rambler's
                          Rest Campground; the area is known as Big Bend and
                          is characterized by a high white sand bank on the
                          east bank of the river. Longitude W82:17:63
                          Latitude N27:02:52. Loran Coordinates 14170.1
                          44219.4


              8 "fixed" stations listed above plus 2 "floating" stations




 I
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                        Summary of Longterm Rainfall Data
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              Rainfall Data Sunmary
              Station: Fort Green Period of Record:         Sep-55      to      Apr-90
                                     Missing data:          Nov-71      Mar-75    and      Feb-76     to       Dec-84


                              YEARS
                 mwm          1955      1956      1957      1958        1959    im            1%1       1%2       1%3        1%4       1%5
                JANUARY                  0,1411     1*070    7,700      3,011     1.020     2.650     1.150     2.620     3.760      1.860
                FEBRUARY                 1.840      7.320    3.310      2.890     5.360     3.570     0.560     8.290     5.570      3.890
                 MARCH                   0.170      4.600    7.810      7.670     5.470     2.230     4.650     1.400     3.170      4.760
                 APRIL                   3.000      5.380    4.060      4.100     2.730     1.840     3.580     0.400     0.440      3.140
                  MAY                    1.470      2.540    3.540      8.950     1.780     2.510     2.460     7.000     4.170      0.130
                  JUNE                   3.150    11.660     9.940      10.070  11.000      7.160    13.550     9.800     4.370     11.650
                  JULY                  11.270    10.890     3.690      8.120   21.560      5.220     5.780     6.410     8.960     16.430
                 AUGUST                 11.780      9.800    2.380      15.070    8.460    13.230    11.740     6.560     5.870      2.980
                SEPTEMBER      6.670     7.140      7.100    2.440      8.930   18.450      1.430    10.760     8.530     5.550      5.190
                0cmm           1.380     2.710      3.610    3.170      6.920     3.080     0.060     1.470     0.400     2.700      1.980
                NOVEMBER       1.510     0.200      3.940    2.000      1.050     0.020     0.970     2.290     5.510     1.540      0.530
                DECEM13ER      0,150     0*11*      2*570    5,190      2.080     2.310     0.570     0.Z10     2.460     1.150      2.350


                 TWAL         10.410    43.670    71.480    55.230      78.870  81.240     41.440    58.260    59.380     47.250    54.890





                 MwFH            1966      1967     1968       1%9        1970  1971          1972      1973      1974      1975       1976
                JANUARY        6.420     0.840      0.340    3.230      2.000     0.520     0.670     5.400     0.040     0.820      1.440
                FEBRUARY       2.570     3.770      2.120    2.280      3.100     4.580     5.370     2.480     1.220     2.270
                 MARCH         0.700     0.360      0.870    7.110      8.510     0.960     5.400     3.440     0.440
                 APRIL         3*450     0,100      0,620    1,300      0*140     0*570     1,800     3*640     0*540     0*710
                  MAY          3.710     0.660      4.430    1.870      8.480     3.300     5.610     2.330     2.010     7.060
                  JUNE         7.830    14.200    13.960     8.290      3.780     8.470     6.700     3.620    11.910     10.710
                  JULY         4.540    17.100      8.920    4.650      3.720     5.000     4.910    10.710    10.450     9.910
                 AUGUST        5.340    10.530      8.580    8.700      4.100     9.850    11.250     7.930     3.640     9.540
                SEPTEMBER      3.300     2.990      3.130    7.630      5.690     6.190     0.480     5.320     3.470     8.580
                0CfOBER        3.680     1.110      3.920    3.970      1.570     8.770     2.900     1.200     0.000     4.910
                NCNEMBER       0.660     0.500      4.040    1.750      0.580               3.460     1.290     0.100     0.500
                DECEMBER       0.670     2.000      1.460    4.990      0.570     1.320     2.940     3.400     2.420     0.730


                 Turn         42.870    54.060    52.390    55.770      42.240  49.530     51.490    50.760    36.240     55.740





                 mm              1985      1986     1987       1988       1989      1990     N       MEAN
                JANUARY        1.960     2.950      1.250    2.000      2.700     0.200        27     2.188
                FEBRUARY       1.150     1.100      0.700    2.500      0.000     4.150        26     3.152
                 Nun           1.980     4.220    10.850     6.150      1.850     1.600        25     3.855
                 APRIL         1.760     1.050      0.180    1.700      1.150     1.900        26     1.892
                  MAY          1.050     1.750      5.540    1.000      0.150                  25     3.340
                  JUNE         6.670    13.020      6.220    1.840      11.750                 25     8.853
                  JULY         1*110     6*400      9*750   10*400      10*210                 25     8.928
                 AUGUST        8.260     8.760      2.500   15.150      6.950                  25     8.358
                SEPTEMBER      4.900     3.640      5.400   10.290      6.650                  26     6.148
                OCIOBER        2.250     2.340      3.000    0.800      1.000                  26     2.650
                NOVEMBER       0.700     0.850      6.300    3.500      1.050                  25     1.794
                DECEMBER       1.250     3.750      0.200    1.200      4.800                  26     2.000

                 TMAL         40.060    49.830    51.890    56.530      18.330                       53.157













                   Rainfall Data Sumary
                   Station:     Myaklm River State Park
                                           Period of Record:         Sep,-43    to        Jan-90
                                           Missing Data:             Apr-49     and       Jan-67     to      Aug-67
                                 YEAR
                       ?KWTH         1943       1944      1945       1946       1947      1948       1949       1950      1951       1952        1953
                       JANUARY                  1.070     1.380      0.910      0.810     4.330      0.640      0.000     0.320      0.740     3.570
                       FEBRUARY                 0.280     0.410      2.700      3.730     0.440      0.340      0.010     1.900      4.250     4.000
                       MA RCH                   2.220     0.160      1.540      7.040     0.490      0.420      1.370     1.350      4.560     0.410
                       APRIL                    0.730     0.000      0.040      3.240     7.020                 0.430     6.220      0.490     3.610
                       MAY                      4.200     0.420      5.330      1.310     1.350      0.620      2.320     0.*610     1.740     0.350
                       im                       7.490   11.800       5.960      12.750    2.870      6.330   10.200       6.450      7.420    12.530
                       JULY                     6.860   14.420       6.950      12.740    9.180      5.950      8.530   12.630       3.840     5.890
                       AUGUST                   5.330   10.740       6.330      8.450     5.480    16.600       7.210     6.360      7.390     6.680
                   SEPTEMBER       6.000        6.840     5.210      6.550      8.510     9.440      8.430      6.300     7.010      6.910     9.950
                       oclCm       6.400        3.380     3.590      2.160      2.330     1.470      1.680      2.350   10.010       9.320     6.050
                       NOVEMBER    0.710        0.200     0.370      0.600      5.040     1.690      2.320      0.020     2.080      3.390     5.130
                       DECEMBER    0.000        0.470     2.110      0.610      2.050     0.790      0.030      3.550     0.540      1.800     2.990


                       WFAL       13.110     39.070     50.610       39.680     68.000    44.550   43.360    42.290     55.480     51.850     61.160





                       mwm           1954       1955      1956       1957       1958      1959       1960       1961      1962       1963        1964
                       JANUARY     2.340        2.170     1.100      1.640      6.820     2.650      1.150      2.520     2.060      2.200     3.030
                       FEBRUARY    1.680        2.810     2.260      5.410      3.740     2.520      4.360      4.970     1.800      6.010     4.260
                       Nun         2.150        1.700     0.080      6.160      8.210     8.800      4.470      1.710     2.520      0.910     4.900
                       APRIL       7.100        1.360     1.940      6.820      2.740     1.700      3.270      3.Z10     5.010      0.450     0.650
                       MAY         5.120        0.500     3.530      5.080      2.900     12.810     2.240      2.360     3.220      5.590     2.260
                       JUNE        8.360        3.530     3.550      11.030     3.740     9.230      5.680      5.150     9.230      6.330     4.500
                       JULY        6.310     10.600       4.480      4.870      7.650     6.750    14.860       5.950     3.550      3.350     7.360
                       AUGUST      5.650        7.170     5.350      11.880     10.370    12.670     7.260      6.310   11.810     14.210      8.510
                   SEPTEMBER      10.690        5.760     9.960      12.820     4.880     8.M      14.040       2.360   22.490       7.420    10.230
                       OCIIOBER    3.350        1.010     5.240      6.290      6.240     7.700      2.500      1.160     0.850      0.300     1.770
                       NOVEM       3.640        0.800     0.410      1.520      4.730     2.300      2.080      0.540     2.360      4.520     1.100
                       DECEMBER    2.710        0.830     0.250      2.100      6.320     2.220      1.760      0.160     0.220      2.640     1.550


                       IWAL       59.100     38.240     38.150       75.620     68.340    77.590   63.670    36.460     65.120     53.930     50.120





                       MXTH          1965       1966      1967       1968       1969      1970       1971       1972      1973       1974        1975
                       JANUARY     0.980        5.130                0.090      2.200     3.350      0.660      0.610     8.250      0.000     0.540
                       FEBRUARY    3.780        3.190                0.850      2.220     1.510      2.390      4.620     1.500      3.390     1.160
                       MARCH       2.270        0.230                1.760      9.740     6.210      1.510      3.480     2.750      0.470     0. M
                       APRIL       1.690        3.240                0.720      0.920     0.120      0.330      2.020     2.570      0.960     0.500
                       HAY         0.830        2.820                6.020      4.930     8.850      2.320      4.800     0.560      3.600     7.950
                       JUNE       12.800        8.110                16.600     10.380    4.660      4.880   13.380       7.160    20.030      8.230
                       JULY       14.330        7.850                13.240     5.210     7.170    10.490       1.810   19.340     10.610     17.730
                       AUGUST     14.540        7.710                8.100      7.490     12.370   18.610       7.870     7.750      5.050     5.830
                   SEPTEMBER       5.520        4.240   11.820       6.310      9.100     5.510      8.490      2.290     8.090      5.460     5.180
                       CCIUBER     5.130        1.310     1.280      2.910      5.110     1.150      5.460      4.640     0.440      0.000     6.090
                       NOVEMBER    0.300        0.540     0.540      2.860      2.480     0.860      1.770      5.010     0.700      0.390     0.580
                       DECEMBER    1.630        0.960     2.090      1.100      3.600     0.460      2.850      3.850     2.110      3.210     0.660


                       WrAL       63.800     45.330     15.730       60.560     63.380    52.220   59.760    54.380     61.220     53.170     55.300











              Rainfall Summ-y, OR ... page 2


                 Mwm            1976     1977     1978     1979      1980     1981     1982     1983      1984     1985     1986
                JANUARY       1.360    2.280    4.900    7.380     3.550    0.660    2.060    2.710     1.000    0.810    1.790
                FEBRUARY      0.490    1.530    5.490    3.070     3.700    5.880    2.670    9.550     2.440    0.970    1.660
                 MARCH        0.600    0.290    3.260    1.150     1.710    1.530    6.620    7.810     5.410    2.800    4.400
                 APRIL        1.000    1.040    0.150    0.660     4.210    0.000    5.050    2.720     3.310    2.090    0.970
                  14AY        7.550    5.330    0.640    4.650     4.010    1.910    2.810    1.990     4.290    0.230    1.940
                  JUNE       10.930    6.990    13.700   3.070     2.490   15.770   15.610    9.330     2.870    5.580.   7.530
                  JULY        6.600   10.150    7.200    7.320     6.480    8.170   13.240    11.890    15.470   7.460    5.580
                 AUG=         5.170    9.100    7.200    13.250    15.990  19.850   11.730    7.410     7.290    9.100    7.090
                SEPIEMBER     9.620   11.080    6.350    21.080    10.150   5.960   11.980    11.670    4.190    9.590    2.400
                ocmm          LZIO     0.610    0.610    1.230     1.030    1.780    3.240    2.660     2.760    1.910    5.920
                NOVEMBER      3.130    3.000    1.080    1.120     4.040    4.870    0.690    4.420     2.360    3.080    1.310
                DECEMBER      1.730    5.970    3.820    2.950     1.150    1.190   .1.020    8.200     0.360    0.410    3.530

                 11DIAL      49*450   57,370    54*400   66*930    58*510  67*570   76*721    80.360    51.750   44.030   44.120





                 MWM           1987      1988     1989     1990    N       MEAN
                JANUARY       4.960    4.490    2.830    0.170        47    2.217
                FEBRUARY      2.540    2.410    0.230                 46    2.720
                 MARCH       12.880    5.170    1.020                 46    3.154
                 APRIL        0.020    1.660    0.730                 45    2.062
                  MAY         5.570    2.630    1.260                 46    3.290
                  JUNE        7*630    3,200    7*680                 46    8.103
                  JMY         9.900    8.670    9.610                 46    8.657
                 AUGUSr       9.510   15.620    5.580                 46    9.152
                SEMEMBER      8.160   11.470    6.890                 48    8.180
                ocmm          4.410    2.140    3.960                 48    3.171
                NOVEMBER      4.120    3.430    1.870                 48    2.085
                DECEMBER      0.190    1.210    4.230                 48    1.962


                 7WAL        69.890   62.100    45.890   0.170













                   RAINFALb DATA: VENICE AIRPORT, VENICE EL
                   PERICID CF Ra= 8/48 - 5/90
                   MISSING DATA: ESSENTIALLY SWISS CHEESE


                          YEAR
                   HIM    1948*    1949*    1950*     1951*    1955*    1956      1957     1958      1959     1960     1%1
                   JANUARY             0.30                0.42             2.13      1.56     9.32      2.60     1.20      2.99
                   FEBRUARY            0.22      0.00      1.93             0.85      6.36     3.26      2.95     4.26      3.64
                   MARCH               0.15      1.54      1.82             0.10      5.42     6.60-     7.74     3.90      1.48
                   APRIL               2.23      0.78      3.20             1.46      13.85    2.29      1.46     3.73      3.87
                   MAY                 0.68                0.36    1.75     3.43      2.10     3.78      7.70     1.83      3.87
                   JUNE                                    3.90    2.45     4.32      7.41     4.30      7.71     1.38      2.01
                   JULY                8.33                        8.28     5.71      6.80     7.00      9.07     10-00     9.13
                   AUGUST     4.70               6.00      4.63    3.04     3.51      10.19    3.28      12.56    7.18      5.70
                   SEPTEMBER                                       6.30     8.99      8.04     3.43      6.71     16.20     1.72
                   OCTOBER    2.35               1.99              1.77     5.06      5.52     6.21      9.61     '4.54     0.74
                   NOVEMBER   1.81               0.21              0.82     0.30      4.77     2.12      2.91     0.15      0.58
                   DE03M      0.90               3.63              1.14     0.83      2.13     4.16      2.26     0.97      0.77


                   mm                                                       36.69     74.15    55.75     73.28    55.34    36.50





                   MlJNTH 1962     1963     1964*     1965*    1%6      1%7       1968*    1969      1970     1971     1972*
                   JANUARY    1.48     2.14      3.68      1.06    6.62     0.84      0.10     2.11      3.00     0.46      1.41
                   FIBRUARY   0.36     5.51      4.92      3.60    3.71     3.35      1.77     2.35      2.09     2.55      5.47
                   MARCH      2.91     0.81      3.10      2.99    0.61     0.39      1.10     7.10      8.05     0.64      4.80
                   APRIL      6.10     0.09      0.62      0.93    4.12     0.00      0.55     0.66      0.17     0.45      0.24
                   MAY        4.98     1.68      1.49      2.17    4.10     0.40      1.98     8.57      2.68     1.74
                   JUNE     12.59      7.66      4.71              6.84     8.10               7.71      3.47     2.46      7.47
                   Jay        2.02     3.35                        4.87     2.33               7.59      3.04     11.23     2.61
                   AUGUST     8.16     4.06                6.04    5.16     16.47     7.67     6.58      13.11    13.41     5.60
                   SEPTEMBER 14.77     9.96      4.78      3.69    7.39     8.53      12.31    7.07      6.68     9.59      5.04
                   OCTOBER    1.52     0.09      0.86      2.77    0.98     7.73      4.19     6.39      0.56     3.24      1.16
                   NOVD=      2.00     5.55      0.54      1.35    0.50     0.56      3.77     3.38      1.48     1.62      5.85
                   DECEMBER   0.33     2.85      2.05      1.01    0.97     2.73      0.76     3.47      0.75     3.24      3.24


                   TOTAL    57.22    43.75                        45.87     51.43              62.98     45.08    50.63






                   MOM    1973     1974     1975      1976     1977     1978      1979     1980      1981*    1982     1983*
                   JANUARY    7.00     0.24      0.43      0.65    2.92     3.21      6.28     2.70      3.20     0.54      2.66
                   FEBRU W    1.77     0.74      1.91      0.71    1.26     5.62      1.51     0.88      0.19     1.81
                   MARCH      3.25     0.40      0.56      1.26    0.33     3.80      1.30     1.80      0.36     5.36      9.46
                   APRIL      2.62     0.26      0.06      1.16    1.62     0.07      0.63     2.95      1.32     4.51      2.67
                   MAY        0.56     1.28      5.61      5.86    0.97     2.41      1.43     2.93      8.04     1.06      2.86
                   i UNE      7.04   11.93       7.33    10.22     2.86     8.59      1.04     1.04      2.12     11.50     7.73
                   JULY       4.06   11.14       4.04      5.23   10.33     6.40      3.71     5.82      16.77    5.29      5.63
                   AUGUST     5.68   13.69       4.60      5.94   11.72     6.11      8.81     7.40      1.84     9.45      8.40
                   SEFIE@ M   7.38     7.62     11.44      5.11    7.39     4.15      9.62     9.14      0.08     9.62     13.23
                   OCHM       0.73     0.20      5.90      2.17    0.77     0.78      1.17     1.71      1.71     8.48      6.65
                   NOVEMBER   0.74     1.41      0.38      2.28    1.75     0.31      1.39     4.46      0.94     0.76      5.56
                   DECDM      2.27     2.81      0.85      2.48    3.82     2.79      3.85     0.84               0.79      6.50


                   TOTAL    43.10    51.72      43.11    43.07    45.74     44.24     40.74    41.67              59.17











                 Rainfall    SumiarN, Venice ... page2


                    MOM      1984      1985       1986       1987       1988      1989      1990*           N       MEAN
                  JANIJARY       1.76      1.33        1.73      2.42       3.22       2.75      0.27          27      2.48
                 FEBRUARY        2.68      0.93        2.20      1.53       1.73       0.15      3.00          28      2.63
                    Ma RCH       6.21      3.64        4.17     11.21       5.80       2.65      1.63          28      2.64
                    APRIL        5.18      3.24        0.69      0.07       2.29       0.59      0.54          28      2.01
                     MAY         4.66      0.99        3.32      3.51       0.70       0.06      3.56          27      2.83
                    JUNE         3.95      2.43        6.14     10.15       1.06       8.50                    25      5.78
                    JULY         12.91     6.31        5.27     11.14       5.04       5.44                    24      6.34
                  AUGLJST        3.49      5.52        6.47      8.06       8.78       5.53                    28      7.54
                 SEPTEMBER       3.79      4.84        2.61      3.87       10.12      8.78                    2@      7.81
                  OCrCEER        1.26      3.06        7.78      2.49       0.75       1.86                    28      2.88
                 NOVEMBER        1.54      2.57        2.68      2.45       3.47       0.98                    28      1.89
                 DOMM            0.44      0.66        5.25      0.18       1.53       4.12                    28      2.07

                 10111           47*87     35*12      18,31     57,01       44,49     41,41                            46.88















































                  *=adssing data




 I
 I
 I
 I                                  APPENDIX C

                      Summary of Physical and Chemical Data
 I                             from Basin Stations
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I                                      C1
 I










                              Dissolved oxygen (mg/1)



  DATE         B110     B120     B130    B140     B150     B160    B170     B180




  19890206    6.75     8.39     2.90    5.20     8.10     6.40   12.10     7.69

  19890227    9.90     8.80     7.15    9.40     10.40    9.90   11.70    10.20

  19890313    9.30     10.40    4.85    7.20     8.35     9.10     8.35   15.40

  19890410    7.50     6.35     3.62    7.50     8.40     9.45   11.00    13.60

  19890501    9.55     5.10     3.60    5.00     7.10     8.14     9.60    8.75

  19890530    3.48              2.45    4.50     6.31     5.30            14.40

  19890626    5.11              6.65    4.30     6.60     6.59     6.92    7.60

  19890710    2.94     8.15     0.71    0.05     6.83     1.76     7.20    7.40

  19890807    4.26     3.83     1.60    0.38     5.39     1.79     5.98    4.25

  19890821    4.39     1.64     1.63    2.00     5.77     3.16     4.75 .' 4.83

  19890911    4.26     0.24     2.62    1.39     7.01     2.44     6.20    6.20

  19891030    5.71     6.06     2.42    4.60     8.20     8.05     7.99    8.98

  19891113    7.41     9.25     4.48    6.30     8.23     7.43     7.58   10.90

  19891204    10.60    12.80    7.70    9.80     11.80    10.80  10.00    13.60



   in         2.94     0.24     0.71    0.05     5.39     1.76     4.75    4.25
 Fmax         10.6     12.8       7.7      9.8   11.8     10.8     12.1  1_11 4 _j












                                           PH




           DATE      B110    B120    B130   B140    B150   B160    B170   B180



        19890118    7.49    8.57    7.10   6.77    7.23   7.26    8.41    6.96

        19890206    6.69    7.35    6.42   7.12    7.58   7.25    8.30    7.10

        19890227    6.75    8.13    7.21   7.78    7.67   7.26    8.18    8.07

        19890313    6.58    7.81    6.22   6.47    6.60   7.50    7.11    8.77

        19890410    6.83    8.88    6.87   7.09    7.46   8.71    7.76    8.64

        19890501    6.68    8.19    6.86   7.13    7.13   6.89    7.92    7.98

        19890530    6.88            6.65   6.59    7.17   7.26            9.05

        19890626    6.36            6.46   6.70    7.04   6.98    7.17    6.97

        19890710    6.43    7.11    6.29   6.38    6.97   6.25    6.94   17.03

        19890807    6.08    6.33    6.  03 5.69    6.63   6.05    6.38    6.77

        19890821    7.14    6.71    6.33   6.38    6.93   6.50    6.48    6.83

        19890911    6.50    6.58    6.25   6.44    6.76   6.37    6.53    6.91
       119891030,   6.83    7.28    6.63   6.88    7.30   7.2.7   7.04    7.10

        19891113    7.06    7.40    6.94   7.16    7.57   7.25    7.06    7.65

        19891204    7.17    7.61    7.37   7.80    7.50   7.85    7.54    7.58



           MIN      6.08    6.33    6.03   5.69    6.60   6.05    6.38    -6.77

           MAX      7.49    8.88    7.37   7.80    7.67   8.71    8.41    9.05

           AVG      6.76    7.53    6.64   6.83    7.17   7.11    7.34    7.56









                               Conductivity (umhos/cm)



       DATE         B110    B120   B130    B140   B150    B160   B170    B180



       19890118     440     475    252     210    920     220    770     400

       19890206     350     710    300     250    690     228    720     283

       19890227     445     490    395     265    780     220    890     421

       19890313     269     1080   280     332    550     265    265     610

       19890410     610     700    449     370    1020    397    660   1080

       19890501     417     600    430     390    1080    439    600   1010

       19890530     351     485    435     510    1190    560          1190

       19890626     348            392     580    880     502            600

       19890710     182     500    197     271    820     334    195     720

       19890807     198     650    200     190    421     191    159     310

       19890821     198     488    214     196    525     209    128     305

       19890911     168'    230    179     185    470     157    133     329

       19891030     260     484    280     189    620     176    141     460

       19891113     279     430    271     201    620     190    176     620

       19891204     265     385    260     220    690     199    201     640



       min          168     230    179     165    421     157    128     283
       max          610     1080   449     580  1 1190T   560    890   1190








                                      Temperature (OC)




   DATE           B110     B120     B130     B140     B150     B160     B170     B180



   19890118      19.0     17.9     21.0     18.0     19.2     17.5     21.0     21.0

   19890206      21.3     20.2     17.2     23.3     23.0     24.1     23.7     24.5

   19890227      13.1     11.5     21.9     17.0     18.0     17.8     18.0     19.0

   19890313      18.5     19.0     19.0     20.5     21.2     21.0     22.5     22.5

   19890410      22.0     23.0     24.0     25.0     24.0     27.0     31.0     27.5

   19890501      23.2     24.5     25.0     26.5     26.0     24.5     31.0     22.2

   19890530      27.0              28.0     29.1     26.1     30.0              31.0

   19890626      25.1              27.0     28.0     28.0     29.0     27.0     29.0

   19890710      28.0     28.9     29.0     31.0     30.5     31.8     32.0     32.0

   19890807      28.0     29.5     29.9     31.0     29.5     31.0     32.0     31.5

   19890821      27.0     23.0     28.0     29.5     29.0     29.5     30.0     30.0

   19890911      27.5     27.9     29.0     29.9     29.0     30.0     31.0     31.0

   19891030      22.0     22.0     22.2     22.8     22.5     23.0     23.0     23.0

   19891113      21.0     21.0     21.0     21.0     22.0     23.0     23.0     22.5

   19891204      14.0     12.0     15.0     17.0     13.5     16.5     16.0     16.0



   min           13.1     11.5     15.0     17.0.    13.5     16.5     16.0     16.0

  ,max           28.0     29.5     29.9     31.0     30.5     31.8     32.0     32.0















            STATION DEPTH TIME         DATE       TSS     DNH4N     DN023N PART C      PART N     PART P 7


            B110       0.20   1100     19890118     0.3   0.037     0.028    0.0962    0.0062-    0.002     1
            B110       0.50   1026     19890206     0.8   0.062     0.030    0.1214    0.0126     0.003     1

            B110       0.20   1031     19890227     0.2   0.029     0.015    0.0592    0.0048     0.017     0

            B110       0.20   1009     19890313     1.3   0.012     0.011    0.1016    0.0080     0.004     1

            B110       0.25   1048     19890410     0.6   0.021     0.019    0.1426   10.0112     0.006     0

            B110       0.70   1030     19890501     .2.8  0.0-20    0.010                         0.092     1

            B110       0.05   0921     19890530     0.8   0.062     0.005    0.0988    0.0054     0.508     1
            B110       0.80   1016     19890626     4.0   0.059     0.005    0.3388    -0.0566    0.167     3
            B110       1.10   1046     19890710     0.9   0.098     0.0.07   0.0886    0.0072     0.070     0
            B110       0.85   1053     19890807     0.8   0.018     0.019    0.1902    0.0124     0.064     1
            B110       0.90   1042     19890821     1.3   0.028     0.009    0.1866    0.0168     0.030     1
            B110       1.00   1047     19890911     0.7   0.005     0.014    0.1582    0.0068     0.039     1
            B110       0.30   1011     19891030     1.1   0.005     0.021    0.1846    0.0072     0.052     1
            B110       0.25   1023     19891113     0.6   0.023     0.012    0.1098    0.0020     0.067     2
            B110       0.30   1122     19891204     0.6   0.016     0.005    0.1190    0.0052     0.049     1


            MIN        0.05                         0.2   0.005     0.005    0.0592    0.0020     0.002     0
            MAX        1.10                         4.0   0.098     0.030    0.3388    0.0566     0.508     3
            MEAN       0.51                         1.1   0.033     0.014    0.1425    0.0116     0.078     1









             STATION IDEPTH     TIME     DATE        TSS     DNH4N     DN023N   PART C     PART N     PART P TU


             B120       0.10    0955     19890118     0.8    0.019     0.005    0.1464     0.0132     0.009     2

             B120       0.50    0910     19890206     1.6    0.028     0.008    0.2652     0.0306     0.014     3

             B120       0.10    0920     19890227     2.5    0.032     0.007    0.7162     0.0646     0.444     2

             B120       0.10    0913     19890313     0.9    0.005     0.005    0.1512     0.0172     0.012     2

             B120       0.35    1004     19890410    12.1    0.025     0.009    1.9869     0.2460     1.650     9

             B120       0.30    0946     19890501    19.9    0.0  22   0.005    3.2273     0.5781     2.787    17

             B120       0.10    0948     19890710    15.3    0.043     0.005    5.3606     1.2113     5.773    is
             B120       0.25    0958     19890807     7.0    0.016     0.018    1.4010     -0.1304    6.064    15
             B120       0.25    0939     19890821     5.0    0.154     0.009    0.7882     0.0626     3.432     9

             B120       0.75    1004     19890911     '8.7   0.034     0.014    1.4985     0.1491     3.760    11

             B120       0.10    0915     19891030     3.9    0.005     0.005    0.6060     0.0674     1.144     7

             B120       0.10    0925     19891113     6.0    0.028     0.005    0.5714     0.0600     0.904    12
             B120       0.10    1027     19891204     5.4    0.010-    0.005    0.6150     0.0574     0.894     7


             MIN        0.10                          0.8    0.005              0.1464     0.0132     0.009     2
             MAX        0.75                         19.9    0.154-    0.018    5.3606     1.2113     6.064    is
                        0.24                          6.9    0.032     0.008    1.3334     0.2068     2.068     9
                                                                       0*005
                                                                       0.00
                                                                     @O . @005









           STATION IDEPTH     TIME   DATE        TSS     DNH4N    DN023N   PART C    PART N     PART P TUR


           B130       0.50    1147   19890118     2.6    0.046    0.014    0.7654    0.0850     0.011     3.

           B130       0.50    1102   19890206     1.9    0.070    0.026    0.43.44   0.0424     0.009     2

           B130       0.50    1116   19890227     1.7    0.029    0.014    0.3690    0.0342     0.110     1.

           B130       0.80    1048   19890313     1.2    0.012    0.013    0.2112    0.0228     0.004     1.

           B130       0.80    1130   19890410     1.4    0.029    0.011    0.3528    0.0388     0.144     1.
           B130       0.85    1110   19890501     1.8    O.Q07    0.005    0.4232    0.0620     0.168     1.
           B130       0.50    1019   19890530     .1.6   0.032    0.005    0.4032    0.0882     0.486     1.
           B130       1.00    1107   19890626     1.2    0.082    0.149    0.1830    0.0366     0.189     1.
           B130     1 1.50    1131   19890710     1.8    0.096    0.007    0.3906    0.0426     0.209     3.
           B130       0.90    1127   19890807     1.1    0.044    0.024    0.2968               0.149     2.
           B130       1.45    1115   19890821     3.8    0.059    0.015    0.4398    0.3524     0.888     3.
           B130       1.15    1132   19890911     1.1    0.005    0.012    0.1612    0.0148     0.094     1.
           B130       1.00    1052   19891030     1.5    0.005    .0.023   0.2212    0.0156     0.087     1.
           B130       0.80    1053   19891113     1.8    0.042    0.014    1.2744    0.1046     0.282     1.
           B130       1.10    1153   19891204     1.0    0.020    0.005    0.1794    0.0132     0.085     1.

           MIN        0.50                        1.0    0.005    0.005    1-0.163.2 0.0132     0.004     1.
           MAX                                    3.8    0.096    0.149    1.2744    0.3524     0.888     3.
           MEA        0.89                        1.7    0.039    0.022    0.4057    0.0681-    0.194     2-.

















            STATION   DEPTH   TIME   DATE       TSS     DNH4N    DN023N  PART C    PART N    PART P



            B140      0.50    1241   19890118    0.3    0.029    0.068   0.4600    0.0502    0.007

            B140      0.50    1151   19890206    0.9    0.029    0.025   0.6710    0.0718    0.012

            B140      0.50    1230   19890227    0.3    0.016    0.011   0.1384    0.0134    0.043

            B140      0.90    1129   19890313    0.5    0.009    0.005   0.3568    0.0474    0.007

            B140      0.80    1208   19890410    0.3    0.015    0.007   0.2206    0.0252    0.058

            B140      0.85    1150   19890501    0.7    0.017    0.005   0.2358    0.0216    0.096

            B140      0.80    1101   19890530    0.6    0.029    0.005   0.2608    0.0490    0.139

            B140      0.70    1137   19890626    0.6    0.041    0.005   0.2802    0.0524    0.131

            B140      1.25    1207   19890710    2.8    0.111    0.005   1.0376    0.1370    0.808

            B140      1.05    1155   19890807    3.4    0.116    0.011   0.2974              0.222

            B140      1.50    1148   19890821    1.9    0.099    0.018   0.4662    0.0450    0.208

            B140      1.75    1338   19890911    0.9    0.024    0.023   0.2312    0.0218    0.084

            B140      1.50    1131   19891030    8.9    0.005    0.014   1.5534    0.2270    0.810

            B140      1.40    1131   19891113    2.2    0.032    0.027   0.6172    0.0868    0.243

            B140      1.30    1235   19891204    3.2    0.017    0.024   0.8032    0.1072    0.362



            MIN       0.50                       0.3    0.005    0.005   0.1384    0.0134    0.007

            MAX       1.75                       8.9    0.116    0.068   1.5534    0.2270    0.810

            MEAN      1.02                       1.8    0.039    0.017   0.5087    0.0683    0.215









            STATION IDEPTH TIME         DATE        TSS      DNH4N     DN023N PART C        PART N     PART P TUR


            B150       0.50     1309    19890118      0.9    0.088     0.252     0.1490     0.0116     0.010      3.
            B150       0.50     1249    19890206      0.9    0.042     0.117     0.1252     0.0106     0.007      3.
            B150       0.50     1315    19890227      1.1    0.028     0.805     0.2088     0.0198     0.152      2.
            B150       -0.85    1207    19890313      2.0    0.038     0.593     1.6162     0.1286     0.013      3.
            B150       0.20     1311    19890410      0.9    0.026     0.010     0.3544     0.0304     0.340      1.
            B150       0.50     1220    19890501      2.5    0.045     0.013     0.2666     0.0178     0.234      1.
            B150       0.20     1137    19890530      2.1    0.043     0.005     0.5100     0.1094     0.515      1 .
            B150       0.35     1206    19890626      1.5    0.083     0.314     0.1846     0.0398     0.238      2.
            B150       0.35     1237    19890710      2.9    0.061     1.419     0.6484     0.0738     0.309      2.
            B150       0.40     1225    19890807      1.4    0.036     0.217     0.1724                0.225      2.
            B150       0.40     1214    19890821      1.2    0.052     0.740     0.1892     0.0136     0.114      1.
            B150       0.30     1405    19890911      5.7    0.010     0.487     0.1236     0.0126     0.096      3.
            -B150   --- 0.30    1157    19891030      0.8    0.005     0.024     0.2134     0.0058     0.097      1.
            B150       0.30     1158    19891113      '0.4   0.015     0.005     0.0542     0.0020     0.079      1.
            B150       0.45     1302    19891204      1.0    0.013     0.036     0.1880     0.0140     0.147      0.


                          n 0                         C'     A . F105  0.005     0. 0542    0.001,        007
            MIN        0.@                            V.4    UoUUD     tj        w w I&            v   %P v
            MAX        0.85                           5.7    0.088     1.419     1.6162     0.1286     0.515      3.
            MEAN       0.41                           1.7    0.039   1 0.336     0.3336     0.0350     0.172      2.


















            STATION DEPTH TIME       DATE       TSS     DNH4N   DN023N PART C      PART N   PART P Tt



            B160      0.10    -      19890118    3.3    0.058   0.082    0.6344    0.0520   0.008
            B160      0.50  11348    19890206    1.1    0.054   0.057    0.2962    0.0310   0.006

            B160      0.50   1431    19890227    0.6    0.044   0.037    0.1884    0.0176   0.060

            B160      0.25   1337    19890313    4.3    0.014   0.008    0.5562    0.0448   0.005      3

            B160      0.05   1416    19890410    2.5    0.032   0.015    0.4614    0.0384   0.151

            B160      0.10   1326    19890501    5.2    0.009   0.005    1.1482    0.1484   1.784      3

            B160      0.05   1231    19890530    8.7    0.287   0.013    1.5660    1.0218   0.744

            B160      0.05   1325    19890626    8.6    0.127   0.027    1.3016    0.2434   0.699      2

            B160      1.00   1409    19890710    4.6    0.055   0.005    2.0051    0.2888   1.136

            B160      0.80   1324    19890807    3.5    0.095   0.011    0.2414             0.160

            B160      0.70   1317    19890821    2.0    0.083   0.030    0.5016    0.0508   0.152      1

            B160      0.85   1506    19890911    1.3    0.009   0.036    0.2842    0.0222   0.244      3

            B160      0.30   1331    19891030    3.5    0.011   0.017    0.7108    0.0892   0.370      3

            B160      0.20  11258    19891113    3.3    0.042   0.024    0.7312    0.0784   0.325      2

            B160      0.10   1402    19891204    .1.6   0.034   0.037    0.6588    0.0858   0.254      3



            MIN       0.05                       0.6    0.009   0.005    0.1884    0.0176   0.005

            MAX       1.00  1                    8.7    0.287   0.082    2.0051    1.0218   1.784      3

            MEAN      0.37                       3.6    0.064            0.7524    0.1580   0.407      3








             -STATION IDEPTH TIME          DATE           TSS_    DNH4N      DN023N PART C          PART N      PART P TUR


             B170        0.05     1648     19890118       0.3     0.005      0.054      0.0412      0.0044      0.002       1.

             B170        0.20     1513     19890206       1.4     0.019      0.053      0.0980      0.0072      0.007       2.

             B170        0.05     1709     19890227       3.8     0.011      0.009      0.3266      0.0238      1.148       4.

             B170        0.05     1525     19890313       1.6     0.019      0.021      0.2648      0.0228      0.026       3.

             B170        0.05     1416     19890410       2.0     0.023      0.009      0.2542      0.0232      1.150       3.

             B170        0.01     1505     19890501       5.0     0.010      0.005      0.5022      0.0436      2.938       3.

             B170        0.10     1504     19890626       5.1     0.101      0.276      1.6392      0.4768      1.826       7.

             B170        0.10     1553     19890710       5.8     0.176      0.024      0.8994      0.0788      1.266       5.

             B170        0.10     1510     19890807       1.1     0.032      0.032      0.2768                  0.328       3.

             B170        0.25     2113     19890821       2.2     0.042      0.017      0.3662      0.0296      0.153       3.

             B170        0.15     1726     19890911       2.0     0.053      0.021      0.4012      0.0304      0.183       2.

             B170        0.05     1530     19891030       1.7     0.055      0.028      0.2874      0.0130      0.268       2.

             B170        0.05     1509     19891113       1.1     0.037      0.021      0.2152      0.0124      0.308       3.

             B170        0.05     1548     19891204       1.0     0.036      0.017      0.1960      0.0088      0.304       3.



             MIN         0.01                             0.3     0.005      0.005      0.0412      0.0044      0.002       1.

             I                                                                     -    11 r_ 12 a 1)n
             1                                            -.8     0 . 1717 6
             ..mxr                                                           0.276                    .4768     11.918      7.
              -_ 41.     0.115            1                   -            I
             MEAN        0.09                             2.4     0.044      0.042      0.4120      0.0596      0.708       3.










             STATION DEPTH TIME        DATE       TSS     DNH4N    DN023N IPART C      PART N    PART P TU
                                                                           I

             B180      0.05     -      19890118    0.8    0.012    0.048    0.1946     0.0134    0.026     7

             B180      0.10    1540    3-9890206   1.4    0.060    0.136    0.2564     0.0210    0.021     6

             B180      0.10    1636    19890227    4.8    0.011    0.011    0.0840     0.0048    0.074     1

             B180      0.20    1501    19890313    0.7    0.005    0.282    0.1312     0.0108    0.004     2

             B180      0.20    1553    19890410    1.5    0.015    0.007    0.1138     0.0078    0.102     0

             B180      0.20    1441    19890501    5.0    0.0-19   0.005    0.1862     0.0140    0.211     0

             B180      0.10    1427    19890530    1.4    0.029    0.005    0.1542     0.0216    0.124     0

             B180      0.35    1441    19890626    1.6    0.073    0.128    0.2252     0.0478    0.204     1

             B180      0.30    1530    19890710    2.2    0.044    0.596    0.4518   1 0.0520    0.411     2

             B180      0.45    1449    19890807    3.1    0.062    0.115    0.5378               0.630     4

             B180      0.45    2046    3.9890821   2.8    0.053    0.139    0.5454     0.0320    0.345     3

             B180      0.30    1700    19890911    3.3    0.019    0.255    0.4474     0.0322    0.423     3

             B180      0.15    1506    19891030    1.0    0.019    0.070    0.1022     0.0001    0.116     1

             B180      0.20    1447    2.0e+07     0.3    0.049    0.006    0.0900     0.0048    0.098     0

             B180      0.05    1530    19891204    0.2    0.005    0.005    0.0624     0.0022    0.093     1



             MIN       0.05                        0.2    0.005    0.005    0.0624     0.0001    0.004     0

             MAX       0.45                        5.0    0.073    0.596    0.5454     0.0520    0.630     7

             MEAN      0.21                        2.0    0.032    0.121    0.2388     0.0189    0.192     2




















                                    APPENDIX D


                        Seasonal Changes in Water Chemist@y
                                 at Basin Stations


                  (Day 0-350 given along the abscissa represents
                       31 December 1988 to 16 December 1989.)





































                                         DI







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 I
 I
 I
 I                                  APPENDIX E

                      Summary of Physical and Chemical Data
 I                             from Estuary Stations
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I
 I                                      El
 I





                                   -------------


















          DATE      E210    E220    E230   E240    E250    E260   E270    E280




       19890117    7.90    7.63    7.74   7.70    7.74    7.23    7.44   7.35

       19890207    8.03    7.92    7.77   7.74    7.73    7.73    7.80   7.76
       19890228    8.03-   8.32    8.34   8.23    7.88    7.99    7.90   8.00

       19890314    8.08    7.88    7.81   7.73    7.62    7.57    7.33   7.71

       19890411    8.01    7.55    7.60   7.50    7.35    7.42    7.45   7.23

       19890502    7.86    7.56    7.64   7.55    7.42    7.35    7.47   7.66

       19890531    8.04    7.68    7.67   7.63    7.54    7.55    7.48   7.55

       19890627    7.88    7.57    7.44   7.30    7.10    6.96    6.90   6.91

       19890711    8.63    8.23    8.43   8.22    7.87    7.61    7.44   7.51

       19890808    7.82    7.17    7.14   6.89    6.92    7.05    6.96   6.91

       19890824    7.56    7.33    7.13   6.82    6.82    6.75    6.63   6.93

       19890912    7.71    7.36    7.12   7.00    6.95    6.80    6.70   6.65

       19891031    7.43    7.46    7.19   6.99    7.04    7.22    7.23   6.94

       19891120    7.50    7.84    7.67   7.73    7.68    7.66    7.75   7.52

       19891205    7.81    7.62    7.46   7.72    7.58    7.51    7.70   7.36



          MIN      7.43    7.17    7.12   6.82    6.82    6.75    6.63   6.65

          MAX      8.63    8.32    8.43   8.23    7.88    7.99    7.90   8.00

          AVG      7.89    7.67    7.61   7.52    7.42    7.36    7.35   7.33













            STATION DEPTH TIME       DATE       TSS     DNH4N    DN023N PART C- PART N       PART P


            E210      1.25    1053   19890117     3.2   0.005    0.007   0.2058    0.0152    0.003

            E210      1.20    1114   19890207     6.9   0.021    0.007   0.923.0   0.0982    0.035

            E210      1.30    1118   19890228     9.8   0.008    0.009   0.6148    0.0546    0.332

            E210      1.40    1129   19890314     5.0   0.009    0.005   0.4334    0.0492    0.010

            E210      1.30    1133   19890411     7.0   0.009    0.010   0.6386    0.0700    0.485

            E210      1.30    0931   19890502   13.6    0.005    0.005   1.3374    0.1758    1.153
            E210      1.35    1013   19890531   12-65   0.012    0.005   0.9050    0.2838    0.162
            E210      1.50    0926   19890627     7.6   0.005    0.005   0.3144    0.0784    0.292

            E210      1.35    1152   19890711     6.2   0.005    0.005   0.5376    0.0702    0.281

            E210      1.00    1340   19890808     7.1   0.007    0.005   1.2042              0.542

            E210      1.50    0743   19890824     5.0   0.032    0.005   0.4456    0.0516    0.487

            E210      1.50    1047   19890912     5.3   0.021    0.005   1.0446    0.0946    0.335

            E210      1.15    1032   19891031     3.8   0.025    0.005   0.2884    0.0198    0.181

            E210      1.20    1128   19891120     4.2   0.024    0.008   0.3592    0.0392    0.205

            E210      1.20    1052   19891205     4.9   0.014    0.005   0.3114    0.0320    0.219



            MIN       1.00                        3.2   0.005    0.005   0.2058    0.0152    0.003

            MAX       1.50                      13.6    0.032    0.010   1.3374    0.2838    1.153

            MEAN      1.30                        6.8   0.013    0.006   0.6376    0.0809    0.315









            STATION IDEPTH TIME          DATE         TSS      DNH4N      DN023N PART C        PART N      PART P TURF


            E220        1.30    1120     19890117       4.3    0.005      0.005     0.5180     0.0502      0.009      1.1

            E220        1.50    1159     19890207       4.0    0.024      0.007     0.3964     0.0524      0.013      1.4

            E220        1.55    1155     19890228       7.7    0.005      0.007     0.8862     0.0734      0.267      2.1

            E220        1.50    1214     19890314     16.1     0.005      0.005     1.5642     0.1672      0.069      7.1

            E220        1.25    1218     19890411     32.2     0.023      0.010     2.4846     0.2762      2.474      13.;
            E220        1.20    1012     19890502       6.3--  0.0132     0.005     0.5358     0.0692      0.458      2.;
            E220        1.25    1059     19890531     25.8     0.013      0.005     2.5553     0.2949      0.160      10.3

            E220        1.40    0856     19890627     10.4     0.005      0.005     0.6936     0.1750      0.868      3.(

            E220        0.70    1228     19890711       9.8    0.005      0.005     1.1854     0.1544      0.846      4.(

            E220        1.10    1425     19890808       6.4    0.006      0.017     0.8740                 0.676      3.1
            -E220       1.20    0816     19890824       8.6    0.016      0.005     0.7868     0.0894      0.626      3.(
            E220        1.40    1150     19890912       8.2    0.005      0.005     1.8976     0.1724      0.627      4.;

            E220        1.00    1102     19891031       4.8    0.021      0.005     1.1902     0.0870      0.312      2.1
            E220        1.15    1208     19891120       2.5    0.058      0.053     0.2362     0.0262      0.165      l.:

            E220        0.90    1135     19891205       3.3    0.072      0.033     0.2818     0.0352      0.205      1.



            MIN         0.70                            2.5    0.005      0.005     0.2362     0.0262      0.009      1.
            MAX         1.55                          32.2     0.072      0.053     2.5553     0.2949      2.474      13.;
            MEAN        1.23                          10.0     0.020      0.011     1.0724     0.1231      0.518      4.;
















            STATION DEPTH TIME       DATE       TSS     DNH4N    DN023N PART C     PART N    PART P



            E230      0.80    1200   19890117     4.1   0.005    0.005   0.6706    0.0670    0.010

            E230      0.70    1231   19890207     3.5   0.028    0.009   0.3580    0.0476    0.010

            E230      1.45    1229   19890228     5.7   0.014    0.009   0.5832    0.0578    0.203
            E230      1.00    1240   19890314     5.9   0.007    0.005   0.4738    -0.0512   0.013
            E230      0.90    1249   19890411   11.5    0.021    0.009   1.0584    0.1142    0.856

            E230      0.80    1047   19890502   12.8    0.0  05  0.005   1.0856    0.1404    0.784
            E230      0.90    1124   19890531   18.0    0.009    0.005   1.0894    -0.3888   0.236
            E230      1.00    1009   19890627   11.7    0.005    0.005   0.9884    0.2644    1.338

            E230      0.90    1255   19890711     5.6   0.008    0.005   1.0826    0.1292    0.571

            E230      0.50    1458   19890808     3.8   0.087    0.065   0.5300              0.461

            E230      1.00    0840   19890824     7.7   0.013    0.005   1.4650    0.1776    0.562

            E230      1.00    1213   19890912   10.1    0.007    0.052   1.7728    0.1850    0.930

            E230      0.65    1128   19891031     3.7   0.026    0.010   0.6734    0.0670    0.420

            E230      0.75    1233   19891120     4.5   0.024    0.065   0.4992    0.0542    0.273

            E230      0.60    1159   19891205     4.2   0.017    0.048   0.3742    0.0390    0.259



            MIN       0.50                        3.5   0.005    0.005   0.3580    0.0390    0.030

            MAX       1.45                      18.0    0.087    0.065   1.7728    0.3888    1.338

            MEAN      0.86                        7*5   0.018    0.020   0.8470    0.1274    0.462









          STATION IDEPTH    TIME   DATE       TSS     DNH4N    DN023N  PART C    PART N    PART P TUR


          E240      0.80    1222   19890117    2.8    0.024    0.013   0.3412    0.0334    0.009     1.

          E240      0.80    1303   19890207    4.6    0.034    0.014   0.8264    0.0934    0.020     3.

         _E240      1.00    1259   19890228    3.9    0.008    0.007   0.4560    0.0562    0.181     1.

          E240      1.00    1300   19890314    4.2    0.005    0.005   0.4630    0.0478    0.009     1.

          E240      0.90    1325   19890411     '6.7  0.014    0.007   0.7524    0.0866    0.558     3.
         _E240      0.95    1151   19890502   10.9    0.0-05   0.005   1.2666    0.1408    0.730     3.
          E240      1.10    1152   19890531   20.1    0.019    0.005   1.6395    0.6197    0.353     8.

          E240      1.10    1034   19890627   10.8    0.005    0.005   1.0744    0.2764    1.149     5.
         _E240      1.00    1315   19890711    8.8    0.033    0.006   1.6187    0.2208    1.172     5.
          E240      0.85    1531   19890808    3.3    0.088    0.077   1.1670    0.0768    0.435     2.

          E240      1.00    0935   19890824    4.0    0.066    0.074   0.5516    0.0588    0.443     3.
         _E240      1.05    1331   19890912    4.0    0.036    0.083   0.5030    0.0606    0.360     3.
          E240      0.80    1248   19891031    3.3    0.005    0.037   0.6434    0.0882    0.415     2.

          E240      0.80    1253   19891120    5.6    0.014    0.019   0.7010    0.0734    0.392     3.
         _E240      0.75    1222   19891205    3.5    0.017    0.010   0.5328    0.0556    0.245     2.


          MIN       0.75                       2.8    0.005    0.005   0.3412    0.0334    0.009     1.
         -MAX       1.10                      20.1    0.088    0.083   1.6395    0.6197    1.172     8.
          MEAN      0.93                       6.4    0.025    0.024   0.8358    0.1326    0.431     3.















            STATION    DEPTH  TIME    DATE       TSS    DNH4N    DN023N   PART C   PART N    PART P



            E250       0.80   1308    19890117    5.8   0.005    0.009    1.0014   0.1106    0.026
            E250       0.70   1329    19890207    4.8   0.018    0.009    0.9438   0.5358    0.018
            E250       0.95   1324    19890228    2.8   0.014    0.010    0.2912   0.0430    0.138
            E250       1.00   1338    19890314    3.4   0.007    0.005    0.5692   0.0560    0.010
            E250       0.95   1357    19890411    5.8   0.015    0.009    0.5592   0.0592    0.421
            E250       0.95   1216    19890502    8.8   0.005    0.005    1.3108   0.1534    0.720
            E250       1.05   1220    19890531   15.9   0.022    0.005    1.3279   0.5075    0.370

            E250       1.15  .1057    19890627   13.9   0.005    0.005    0.9792   0.2584    0.885

            E250       0.80   1415    19890711    7.0   0.112    0.025    1.2926   0.1512    0.832

            E250       0.85   1550    19890808    3.2   0.074    0.071    0.5048   0.0516    0.297

            E250       1.05   0953    19890824    3.2   0.064    0.081    0.4430   0.0438    0.321

            E250       1.15   1350    19890912    2.3   0.036    0.076    0.4078   0.0410    0.277

            E250       0.75   1308    19891031    2.0   0.007    0.067    0.5212   0.0556    0.314

            E250       0.80   1317    19891120    5.5   0.008    0.005    0.9680   0.1074    0.460

            E250       0.75   1240    19891205    3.2   0.015    0.007    0.5446   0.6672    0.294



            MIN        0.70                       2.0   0.005    0.005    0.2912   0.0410    0.010

            MAX        1.15                      15.9   0.112    0.081    1.3279   0.6672    0.885

            MEAN       0.91                       5.8   0.027    0.026    0.7776   0.1894    0.359















           STATION   DEPTH   TIME    DATE       TSS     DNH4N    DN023N   PART C    PART N     PART P TURI



           E260      1.00    1400    19890117    6.5    0.005    0.005    1.7278    0.1914     0.036     4.

           E260      0.80    1614    19890207    5.8    0.027    0.006   11.2336    0.1266     0.030     4.
           E260      1.05    1423    19890228    2.0    0.017    0.007    1-0.5278  0.0510     0.168     1.
           E260      1.20    1356    19890314    4.2    0.005    0.005    0.6184    0.0584     0.013     2.
           E260    1 1.10    1508    19890411    5.2    0.010    0.008    0.8154    0.0836     0.416     3.
           -E260     1.20    1258    19890502    7.8    0.0.105  0.005    1.4710    0.1706     0.728     4.
           E260      1.25    1259    19890531    11.1   0.020    0.005    1.4560    0.5424     0.344     5.
           E260      1.30    1212    19890627    6.2    0.005    0.005    0.7510    0.2140     0.689     3.
           -E260     1.00    1523    19890711    4.8    0.074    0.021    1.5034    0.1850     0.801     3.
           E260      0.95    1749    19890808    2.8    0.077    0.063    0.4840    0.0510     0.290     2.
           E260      1.25    1026    19890824    2.6    0.062    0.072    0.4012    0.0408     0.246     2.
           E260      1.25    1426    19890912    1.3    0.026    0.050    0.2900    0.0304     0.198     1.
           E260      0.95    1337    19891031    1.8    0.029    0.091    0.4238    0.0420     0.257     1.
           E260      0.90    1412    19891120    3.8    0.011    0.010    0.8878    0.1002     0.380     2.
           E260      0.95    1919    19891205    3.0    0.009    0.048    0.6096    0.0348     0.284     2.


           MIN       0.80                        1.3    0.005    0.005    0.2900    0.0304     0.013     1.
           MAX       1.30                        11.1   0.077    0.091    1.7278    0.5424     0.801     5.
           MEAN      1.08                        4.6    0.025    0.027    0.8801    0.1281     0.325     3.










            STATION   DEPTH   TIME   DATE       TSS     DNH4N    DN023N IPART C    PART N    PART P


            E270      1.00    1418   19890117    6.7    0.005    0.005   1.8278    0.1722    0.034

            E270      1.10    1550   19890207    6.0    0.019    0.007   1.4898    0.1362    0.033

            E270      1.30    1510   19890228    3.2    0.012    0.007   0.7132    0.0634    0.290

            E270      0.90    1414   19890314    4.7    0.005    0.005   0.8632    0.0820    0.022

            E270      1.10    1537   19890411    5.3    0.012    0.007   0.9374    0.0866    0.435

            E270      1.20    1321   19890502    8.0    0.005    0.005   1.3678    0.1472    0.626

            E270      1.25    1321   19890531    8.1    0.010    0.005   1.5080    0.5514    0.721

            E270      1.40    1233   19890627    6.7    0.005    0.005   0.6424    0.1750    0.563

            E270      1.10    1552   19890711    5.7    0.089    0.021   1.2478    0.1532    0.745

            E270      1.10    1805   19890808    1.9    0.071    0.061   0.5712    0.0544    0.306

            E270      1.25    1050   19890824    1.1    0.078    0.076   0.2924    0.0264    0.470

            E270      1.50    1444   19890912    0.8    0.013    0.050   0.1684    0.0206    0.144

            E270      1.00    1356   19891031    1.9    0.009    0.091   0.5584    0.0542    0.336

            E270      1.05    1430   19891120     .2.7  0.025    0.062   0.6314    0.0592    0.270

            E270      1.10    1400   19891205    2.5    0.025    0.108   0.4436    0.0284    0.216



            MIN       0.90                       0.8    0.005    0.005   0.1684    0.0206    0.022
            MAX       1.50                       8.1    0.089    0.108   1.8278    0.5514    -0.745
            MEAN      1.16                       4.4    0.026    0.034   0.8842    0.1207    0.347









          STATION IDEPTH    TIME    DATE       TSS      DNH4N    DN023N   PART C    PART N    PART P TURB


          E280      1.75    1455    19890117     5.1    0.005    0.009    1.1110    0.1228    0.026     3.0

          E280      1.70    1521    19890207     8.0    0.026    0.009    1.6230    0.1472    0.036     3.8

          E280      1.55    1549    19890228     3.4    0.017    0.007    0.8986    0.0892    0.399     2.5

          E280      1.75    1434    19890314     5.6    0.005    0.005    1.3356    0.1166    0.036     3.0

          E280      1.80    1616    19890411     5.2    0.019    0.007    1.0186    0.0958    0.551     3.7

          E280      1.55    1347    19890502     8.7    0..005   0.005    1.8830    0.2100    0.784     4.3

          E280      2.20    1359    19890531     7.8    0.030    0.005    1.5120    0.5636    0.359     4.0

          E280      2.00    1256    19890627     7.2    0.005    0.005    1.1868    0.3156    0.856     3.9
          E280      1.50    1611    19890711     7.3    0.093    0.015    1.6382    0.1870    1.038     3.4
          E280      1.40    1823    19890808     3.5    0.072    0.058    0.6734    0.0616    0.415     2.3
          E280      2.00    1111    19890824     '1.1   0.064    0.069    0.3208    0.0280    0.113     1.2
          E280      1.75    1506    19890912     0.9    0.015    0.048    0.1366    0.0208    0.115     1.1
          E280      -1.25   1418    19891031     2.0    0.033    0.085    0.3784    0.0266    0.249     1.6
          E280      1.75    1452    19891120     2.0    0.037    0.116    0.5076    0.0472    0.236     1.9
          E280      1.80    1425    19891205     2.0    0.051    0.107    0.3052    0.0186    0.161     1.5
         @
          MIN       1.25                         0.9    0.005    0.005    0.1366    0.0186    0.026     1.1
          MAX       2.20                         8.7    0.093    0.116    1.8830    0.5636    1.038     4.3
            IN

             X
          MEA@N     -1.72                        4.7    0.032    0.037    0.9686    0.1367    0.358     2.7

















            STATION   DEPTH   TIME   DATE       TSS     DNH4N    DN023N  PART C    PART N    PART P



            E215      0.50    1116   19890912    8.4    0.009    0.005   1.4096    0.1302    0.447

            E215      1.50    1127   19890912    9.1    0.005    0.005   1.7424    0.1490    0.598

            E232      0.50    1349   19890711    6.7    0.011    0.005   1.5570    0.1812    0.781

            E232      0.40    1645   19890808    2.9    0.102    0.076   0.5396    0.0694    0.405

            E232      1.00    1230   19890912    4.9    0.046    0.083   0.6558    0.0830    0.522

            E232      0.65    1153   19891031    5.5    0.042    0.026   0.7916    0.0812    0.514

            E234      0.80    1707   19890808    2.5    0.083    0.081   0.4600    0.0542    0.387

            E234      1.10    1254   19890912    4.0    0.043    0.085   0.5554    0.1016    0.450

            E235      0.70    1235   19890117    3.4    0.005    0.005   0.3918    0.0376    0.009

            E235      0.85    0901   19890824    6.0    0.043    0.036   0.7202    0.0780    0.583

            E238      1.00    0921   19890824    4.5    0.053    0.061   0.5032    0.0530    0.397

            E238      0.70    1208   19891031    4.5    0.009    0.033   0.7920    0.0968    0.555

            E255      1.10    1635   19890711    5.7    0.083    0.021   1.4630    0.1782    0.823

            E255      1.10    1337   19891120    4.8    0.014    0.005   0.9134    0.1086    0.401

            E255      1.05    1300   19891205    3.5    0.013    0.019   0.7014    0.0696    0.302









           STATION IDEPTH     TIME    DATE        TSS      DNH4N    DN023N    PART C    PART N     PART P TURB


           E264       0.80    1641    19890207     7.0     0.038    0.009     1.5242    0.1440     0.030      4.6

           E265       0.60    1526    19890117     8.9     0.005    0.005   1 2.1282    0.2180     0.042      5.5

           E265       0.70    1640    19890228     4.2     0.011    0.006     0.8906    0.0840     0.263      2.7
           E265       0.90    1525    19890314     4.2-    0.025    0.005     0.6998    0.0738     0.016      2.9
           E265       0.80    1523    19891120     3.4     0.015    0.050     0.4148    0.0422     0.311      2.3
           E265       0.75    1504    19891205     3.2     0.0  19  0.087     -0.3742   0.0610     0.339      2.2
           E268       1.80    1656    19890207     6.5     0.057    0.007     1.3228    0.1258     0.030      4.2
           E274       -1.35   1726    19890411     5.8     0.012    0.008     -1.1964   0.1104     0.517      3.6
           E275       0.80    1616    19890228     3.5     0.014    0.007     0.9264    0.0850     0.372      2.8

           E275       1.55    1501    19890314     5.0     0.015    0.005     0.9918    0.0864     0.028      3.4
           E275       -1.20   1537    19890502     8.2     0.009    0.005     1.5724    0.1500     0.640      3.5
           E276       1.60    1649    19890411     5.0     0.024    0.007     1.1604    0.1042     0.521      3.3

           E290       1.10    1511    19890502     7.9     0.009    0.005     1.8658    0.2068     0.718      4.3

           E290       1.20    1425    19890531     5.9     0.013    0.005     0.8444    0.3026     0.402      3.7

           E290       1.25    1403    19890627     7.7     0.005    0.005     1.2972    0.3586     0.936      5.2

           E300       1.10    1448    19890531     4.2     0.012    0.005     0.6516    0.2286     0.453      3.0
          IE300         20__L 1226   119890627   1 7.8     0.005    0.005     1.2770   10.3578     1.090      5.2




















                                    APPENDIX F



                 Monthly Distributions of Nutrient Concentrations
                                at Estuary Stations


                (Concentrations of nutrients in samples collected
                from the eight freshwater stations are indicated
                      on the graphs left of zero salinity.)




































                                        F1







                              MYAKKA RIVER                    ESTUARY TRANSECT


                                         I-         Am                             40
                                     1/89                            5/89                           9/
                    so                              so


                                                                                   is






                                  10     so   w            0     10           so




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                    0                               0
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                                                       SALINITY (ppt)






                                                                                  MYAKKA RIVER                                                                  ESTUARY TRANSEC


                                                                                                   1/89                             CLIO                                       5/89

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                                                      MYAKKA                         RIVER                      ESTUARY TRANSECT


                                                                                           02() 1-7-1-                            1-                a=
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                                                                                                  SALINITY (ppt)






                                                                    MYAKKA RIVER - ESTUARY TRANSEC


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                                               028                                                             026                                                              Q26


                                               cm
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                                                            m             m             m             m             mis4 Ll"T Ymn(p*16                                       m            m







                         MYAKKA RIVF--R             ESTUARY TRANSECT


                               1/89.                     5/89                      9/

                                           2





                 0
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                 a             2/89                      6/89                      10

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                                             SALINITY (Ppt)







                                                                                                                        I -UARY TRANSECI
                                                            MYAKKA RIVER                                               E--S"71


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                                        =8   F                           1/89                     007a                             5/89                     QMa

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                                                                                                          SALINITY                     (ppt)






                                                                                                                          MY,4KKA RIVER                                                                                                                   ESTUARY TRANScFCT


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                                                                                                                                                                                                                             SALINITY (ppt)







                                                          M"'@AKKA RIVER                                           ESTUARY TRANSECI


                                        02                         ---- -                                                            I -
                                                                       1/89                                                    5/89

                                        OA                                                      CA



                                                                                                02

                                                                                                      14
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                                                       0         10         20         00                      0         10          20        so




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                                        00
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                                        00
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                                        a2



                                        w
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                                                                                                      S A LIN IT Y,
                                                                                                     = = M@pp@m






                            US Department of Commerce
                            FOAA Coastal Services Center Library
                            2234 South Hobson Avenue
                            charleston, sc 29405-2413

































































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