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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 iii 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 iv 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 vii 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. ix 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. x 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. xi 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 V;;z 33 7 1 T 3-1 T4q T JG 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 "49M Uod 4420H ATTUG JStMV9A TTY poob 4ussead - V861 'UVV 7a '4Z GIM *00 940ov"s BST14TMn *03 9408V"S obnvb 19JOCK v Seaga ATTVG X9tPVQA TTY poob 4ussead - 986T 'bnV CDM *03 U40991wo BOT4TTT'4fl *00 v4029"S - ATTva 4SWOnq buT'qbTOA 102007A 13 BOK90 'Obnub mq4v9A TTY poob 4tmsezd - So6i Ibny mm * co 9408v"s 99TIMM *00 V1408VIvO ATTva :tDXDnq buTt[bTOA jazoom I Seaga 'Obnvb ZGIPvDA TTY poob 4u9s"d - 986T 'bnV mm *Cc U408navs 89MMn *03 v4Os=vs ATTUG '49WOnq buTtibTOA I Ulzoom 9 Baum lobnvb JQtRvSA TTY poob W9882d - 986T 'bnV aNs loo IM089"s 69TIMM *00 vZogu"S ofinub gazoom I somw AT*Mm JStMV9A TTY poob W989-ld - 986T 'buY obnab OOTA"S X"d ATTWO 2944WA TTY poob 4ussead - 986T 'tMr IDA7 obnvb OCTAXOS X"d ATTva Xsq4vsA TTY poob 4ussaid - 9861 'Uvr -MAI abnvb 9OTAJ98 X"d ATTva "q4v9A TTY poob 4ussead - 986T luvr "Al obnvb 90TA"S X"d ATTvG "q4v9A TTY poob 4ussead - 9861 'Uwr JDAJ AZ%UGDV AZUarLD"a W)TABG susue4olumoo 1 PaOOO-d ;o POlaad UOT uOT40OTTOD uOT400TIOD ATTeno V4VQ *SUOT4v4S TTVJuTVX amr4-44ORB PER G,4IxFpQUXw4uT .2047 uOT4vMXo7uT uDT400TIcc Pug Pxcmx JIO PO ss/T/V asq,;v poob abnvb SPXOOBI 9996T cm JOTad 009tri vvw ATTVG X9q4v*A TTY 049TCIM-OuT AJOA V4Va 4ussoad - at/T/9 octoLa poob splooex obnvb ZOR40 9L96T 'bnV 04 SZOTI Yvon ATTVCJ J9q4vQA TTY 1.96T 'Uvr WZVP buTGOTM 4ussead - Et/T/6 TEM poob SWOO9.1 bnvb Moze won ATTva "= TTY 9l6xT*q'c4[gJfWt48v6Tp b'OUTTGOOOT'N4 4ussead - 55/T/6 MEtz AOUODV ADUO Oza OOTAOa OBOU6461COOD 13 P1008d ;0 POTIOd uOT; UOT409TTOD uOT:PDTTOD AMM 9:tvCl I=WT4v4s TTVXUTW Umq-uwt .10.7 Un4vwmm UoTqMTTCM Puv Paco" J;o VCVT 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 el or -Lo .I... II- @ I 'IS . - 64. w At .10 - $ TOT rf - " Vol M. .4^. 1 9 .. . I . I j- 41 0 0 Sir 07 v IAIC Al I led ir 14 a --hMl D- 14 1r J13A 101 lot, X. % fij i I I, . I, - 1. 1 ,.d& :.4, I - . 0 P. P, L! ;6 '0 *> 0 0 7 tu fe So [Vow M I*; -n -Z": 04IN0 oo Ik I, r T7 --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 4"o- low@ 6-"- 41M. C C Avg- 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 0 co w 0 DO (mg/1) DO (mg/1) - 0 P.> -Al 01A 00 8 1-) -b.. @cn co m 0 t") -t@ m co - I , I r-r-r-r-r-rT-r-r- r-r- 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 02-27 - 11 co Cn 03-13 00 0 .1 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 05-30 -104D 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 I I I APPENDIX A I Basin and Estuary Station Descriptions I I I I I I I I I I I I I Al I 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 I I I "PENDIX B Summary of Longterm Rainfall Data I I I I I I I I I I I I I I BI I 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 MYAKKA RIVER 8 tationO B 110 U10 so am m am do Im 1@ sm 6 la is w 06 an 0 so im 160 WO 2w wo ow W, m m as CL4 at 02 OA 0 0 all co ab 0 8D 100 Im WO M sm sm a so w 00 L 0 LA 0 a OD Im "o ow OW am ow MYAKKA RIVER Station# B 120 io 0 aw I 0 v sw UO mNo am m a m to ts ID so w IE 00 L ae 0 so lw $0 so a a w m so an 00 00 00 lw wo msm sw 1w w m am av a Le 0 ID M M w w m 0 a Im we sm MYAKKA RIVER Station# B 130 am m we m Mo sw we we so m as an aoL "I - Q... 9 Go, 0 so 100 "a -Wo sw so le m m m of as as OA GA 02 (W 0 so W ISO Sao no sm am 0 a Im No sm w IA lb all 0* 0 as a 0 00 0 so 1w m m w m m MYAKKA RIVER Station# B 140 so "-*too 00 es 49 OW 0 so w m w m w me sm w w w w as w 00 00 so 0 0 4D im ue sm 20 sw so 0 a we un we ce w a@ OA aA an 0 so $W U10 2w no wo so a m Im 10 IA 10 is W son 00 0 so we m Im sm we MYAKKA RIVER Station# B 150 Ow We 0 so 100 ISO 'm so sm so me ts w 00 ao 0 me sm Ise sm m No so a a m m m as CL4 ag ao a so M lw 2w Im sw m a a w IA so w an 00 0 so 40 so Ow w MYAKKA RIVER Station# B 160 am 1w we w W as an a.&* a 2* 0 so im M wo 2w so so 0 a we me we aA aA CM 00 0 v wo lw wo m sw Ow "0 w 10 me m Statlon4 B170 NVAKKA RIVER um wv r w vo IW 2W 'o as[ Im SW WO MYAKKA RIVER Station# B 180 09% am 10 an 0 w $W IM xv 2w em w w IE cw A4 - .2 0 w lw lw am "0 sw m as cm w 110 Ow w wo m 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 40 40 a w 2/89 so 6/89 10 W io 0 . . . ....... a $0 0 10 0 10 0 0 40 40 Am Q w 3/89 7/89 w 0 0 so 20 w 0 10 so w 0 40 40 a to 4/89 w 8/89 12 'o 10 so 0 0 0 io V so 0 10 w a 10 SALINITY (ppt) MYAKKA RIVER ESTUARY TRANSEC 1/89 CLIO 5/89 dio CLIO dia am Om ow L to so 0 10 20 SO 10 Ox 020 am ota 2/89 ale 6/89 aid 010 010 oic L 009 Om Ow OW L o L-..-- -A L 0 so 0 10 20 so 0 10 ale 3/89 ala 7/89 ato alo Wo I- 005 am Oas 0 10 20 30 0 10 20 so 0 10 aw - 020 ------- am 018 COO alf 4/89 8/89 010 dio alo Om 005 ODO m 000 0 10 70 so 0 to 20 so 0 10 A 1@6 i T @m pi@ MYAKKA RIVER ESTUARY TRANSECT 02() 1-7-1- 1- a= 5/89 9/8 ale 1/89' ale ale 010 alo alo 006 Clos am ow 000 0,00 0 10 20 80 0 10 20 so 10 Ow 020 020 E ale 2/89 ale 6/89 ale 10/ alo d'o 006 ocs oce 0,0 q. 000 ow -j - - - . .- ... - a 10 20 30 0 10 20 00 0 10 020 020 7- 0 ale 3/99 ale 7/89 ale Clic Clio alo 0 oce 006 006 000 L* oco 1 000 0 10 20 DD 0 10 20 80 0 10 am am ale 4/89 .1/89 ale 12) C110 a, olo am oce 0100 000 0 to 20 80 0 10 20 80 0 10 SALINITY (ppt) MYAKKA RIVER - ESTUARY TRANSEC 1/89 5/89 080 T om Q28 028 026 000 ow so 0 10 20 so 0 10 OTS - - -- I---- -'r (179 7 - - -------- 2 89 6/89 Ow Ow ow C@ Q28 028 wa 000 O.W ow 0 10 20 so 0 10 20 so 0 10 0 n al's wa als aw 3/89 am 7/89 om 028 026 Q26 cm ---------- 1. t . - - I- -j 000 L 0000 0 10 20 30 0 10 20 30 $0 We we ow 4/89 cm 8/89 ow 025 028 .4 an Om ------ 0 10 20 m 0 10 20 so 0 to m m m m mis4 Ll"T Ymn(p*16 m m MYAKKA RIVF--R ESTUARY TRANSECT 1/89. 5/89 9/ 2 0 0 io 20 80 0 io 20 a 2/89 6/89 10 2 2 0 10 20 w a 10 20 so 0 n a 3/89 7/89 2 2 4 0, a 10 20 30 10 20 so 4 4/89 8/89 12 2 I 0 0 10 20 so SALINITY (Ppt) I -UARY TRANSECI MYAKKA RIVER E--S"71 WOO alco aloo ----------- =8 F 1/89 007a 5/89 QMa 0000 0000 om om ozw 10 20 w 0 10 20 so 0 10 aloo r- ----- r aloD dloo Owa oma cma 2/89 6/89 am 0000 OMS IA ,I= 7 .0 0 10 20 30 0 10 20 w 0 10 n n (lim oms owa owa 3/89 7/89 om Qow oma Olga .... ...... L 0 0 10 20 SO 0 10 20 SO 0 10 COOD WOO - aloo 4/89 oma .1/89 oma om om om, om o= am ------- L am 0 $0 20 DO 0 10 20 80 0 10 SALINITY (ppt) MY,4KKA RIVER ESTUARY TRANScFCT - - 20 w 1/89 1891, 9/ ,a 10 io io 0 10 20 so 0 'o 20 so 0 io 20 20 20 2/89 la 6/89 10 10 v IE L* 08 0 10 20 w 0 10 w 30 0 10 C/D C/D 20 20 to 18 la 7/89 3/81 10 io io 0 o 0 LLD- 0 10 20 so 0 10 20 so 0 $0 20 w . . ............. . ... . 20 le 4/89 la 8/89 Is 10 10 a 0 o 10 20 w 0 10 w ao 0 10 SALINITY (ppt) M"'@AKKA RIVER ESTUARY TRANSECI 02 ---- - I - 1/89 5/89 OA CA 02 14 w @- @,.. .. . . .0- . 0 10 20 00 0 10 20 so 08 08 GA 2/89 OA - 6/89 w L 02 00 10 20 30 0 10 20 so n 08 -- - -- 08 OA 3/89 OA 7/89 02 02 00 a 10 20 so 0 10 20 so 06 - -.. - -- -- * - r-- ---. C" 4/89 8/89 a2 w 0 10 20 so 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 3 6668 14102 0224