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




































                                   CHEATHAM ANNEX PROJECT


                              DEPARTMENT OF ENVIRONMENTAL SCIENCES
                                     UNIVERSITY OF VIRGINIA
                                   CHARLOTTESVILLE, VA 22903


                                      NOVEMBER 19, 1990










                                          COASTAL ZONE

                                       INFORMATION CENTER











       TD
       425
        C54
       1990
















                                                                                    





                                                                          
                                   CHEATHAM ANNEX PROJECT



                                   Department of Environmental Sciences
                                           University of Virginia
                                         Charlottesville, VA 22903



                           Submitted to Virginia Department of Waste Management


                                            November 19, 1990





                                             Janet S. Herman
                                           George M. Hornberger
                                              Aaron L. Mills
                                           J. Robert Hoelscher
                                              Scott C. Brooks
                                              Alison E. Clark
                                              Charles H. Hall









                                           U.S. DEPARTMENT OF COMMERCE NOAA
                                           COASTAL SERVICES CENTER
                                           2234 SOUTH HOBSON AVENUE
                                           CHARLESTON SC 29405-2413


                                           property of CS0 Library
 











         Acknowledgement

              This study was funded, in part, by the Virginia Council on the
         Environment's Coastal Resources Management Program through grant
         number NA89AA-D-CZ134 of the National oceanic and Atmospheric
         Administration under the Coastal Zone Management Act of 1972 as
         amended.














                                   CHEATHAM ANNEX PROJECT



                                       ADDENDA AND ERRATA



                                   Department of Environmental Sciences
                                            University of Virginia
                                         Charlottesville, VA 22903



                           Submitted to Virginia Department of Waste Management

                                             December 10, 1990







                                              Janet S. Herman
                                           George M. Hornberger
                                               Aaron L. Mills
                                            J. Robert Hoelscher
                                               Scott C. Brooks
                                               Alison E. Clark
                                               Charles H. Hall








                                        Revisions to Chapter 2: HYDROLOGY


                      The hand-augered well installation can be more completely described than was done on
              page 10 in our report. Each hole was hand augered to the total depth listed in Table RI. PVC
              pipe of the diameter listed in Table Ri was perforated with a power drill at one end of the pipe
              section for a length listed in Table R1. The perforated portion of the pipe was wrapped in nylon
              screen. The bottom end of the pipe was capped. The pipe was placed in the hole, and, thus, the
              screened interval is from the total depth of the hole to the distance of the screened length toward
              the ground surface. The well was finished off as described on page 10.


              Table R1. Well installation details.

              Well Name                Casing                  Total Depth                      Screened Length
                                       Diameter
                                       (inches)                    (M)                                (M)


              UVALP-3                       1                           1.32                             0.52
              UVALP-4                       1                           0.87                             0.38
              UVALP-5                       1                           1.32                             0.37


              UVAPZ-1                       1                           2.53                             0.30
              UVAPZ-2                       1                           4.88                             0.30
              UVAPZ-3                       1                           6.71                             0.30
              UVAPZ-4                       1                           2.74                             0.30


              UVANW-1                       1                           0.48                             0.30
              UVANW-2                       1                           1.04                             0.30
              UVANW-3                       1                           2.18                             0.30
              UVANW-4                       1                           1.52                             0.30
              UVANW-5                       1                           2.44                             0.30
              UVANW-6                       1                           1.05                             0.30
              UVANW-7                       1                           0.65                             0.30
              UVANW-8                       1                           1.08                             0.30
              UVANW-9                       1                           0.69                             0.30
              UVANW-10                      1                           0.84                             0.30
              UVANW-11                      1                           1.38                             0.30
              UVANW-12                      2                           0.84                             0.40
              UVANW-13                      2                           0.80                             0.40
              UVANW-14                      2                           0.76                             0.40
              UVANW-15                      2                           0.73                             0.40





A





.4










                    Soil moisture potential in the vadose zone is related to the water content of the soil. Soil
            moisture potential measurements were made in the field as part of this study using a tensiometer.
            Strictly, a tensiometer measures the matric potential of a soil for soil suction values between 0 and
            I bar. The tensiometer consists of a porous cup attached to the bottom of a rigid plastic tube. The
            measuring device connected to the tensiometer is the pressure transducer. The electrical output
            from the transducer was recorded by the data logger. An excellent source of detailed information
            on this device is available in Morrison, R.D., Ground Water Monitoring Technology: Procedures,
            Equipment, and Applications, published byTIMCO Mfg., Inc.
                    Please note that there is also a misspelling on page 10. The reference tensiometer was
            used for removing temperature biases (not "beases").


                    The location of the seepage meters:
                            Seepage meter 1 at Station 1
                            Seepage meter 2 at Station 4.


                    The word theodolite is mispelled in the original report (as "theotolite" on page 12). A
            theodolite is a common surveying instrument used in determining horizontal and vertical angles.


                    In the analysis of the hydrologic data, we determined that the stream floodplain area was
            the primary area contributing drainage to the surface water (i.e., stream and pond) during storm
            events. This statement implies that other areas of the watershed than the floodplain were less
            significant in contributing drainage to surface water during storm events.


                                                  3
                    The units in Table 2. 11 are m .































                                                               2








                                       Revisions to Chapter 3: ORGANICS


             Table R2. Dates of analyses of organics samples.

             Sample Name                    Date of analysis


             S-4                            8/27/90
             S-5                            8/27-28/90
             S-6                            8/28/90
             S-7                            8/28/90
             SW-5 (9/3)                     10/2/90
             SW-9                           10/2/90
             SW-10                          10/3/90
             SW-11                          10/4/90
             LW- 1                          10/5-7/90
             LW-2                           10/8/90
             SW-6 (9/3)                     10/8/90
             SW-8 (9/3)                     10/9/90
             SW-8 (8/2)                     10/9/90
             SW-12                          .10/10/90
             SW-6 (8/2)                     10/10/90
             SW-5 (8/2)                     10/10/90
             S-1                            10/11/90
             S-2                            10/11/90
             S-3                            10/11-12/90
             S-7r                           10/12/90
             UVAPZ-4                        10/15-16/90
             UVALP-3                        10/16/90
             UVA-PZ-4s                      10/16-17/90
             UVALP-3s                       10/17/90




                    The pore size of the filters employed in the preparation of samples for organics analysis
             were
                            Whatman no. 1 = 11 Am
                            Whatman no. 4 = 20-25 Am.


                    The samples names WW-14 and WW-15 were inappropriately used on page 58 of the tinal
             report. Those sample names should be replaced by the names used consistently throughout the
             rest of the report:
                            UVAPZ-4 replaces WW-14
                            UVALP-3 replaces WW-15.


                    On page 59 of the final report, the PNA's were reported as approximately 10,000 ppm tor
             sample S-5. This statement is incorrect. Rather, TEH is approximately 10,000 ppm for sample S-
             5 and is so correctly reported in Table 3.3.


                                                              3








                                      Revisions to Chapter 3: NffiTALS


                   The results of the metals analyses that we report were provided by Mike Lockhart of
            Havens Laboratory in Charlottesville, Virginia. Mr. Lockhart had been working with Yacov
            Haimes and Ralph Allen in work on this project before the Department of Environmental
            Sciences became involved. We have listed in Table 4.3 of our report everything that was made
            available to us by Mike Lockhart or Yacov Haimes regarding the water samples that we had
            collected. We do not have information on dates or methods of sample analysis or on sample
            pretreatment or storage. We never received any information on the analysis of sediment samples
            that we had collected.























































                                                           4









                                                 EXECUTIVE SUMMARY


                      The study of the Cheatham Annex site conducted by members of the Department of
              Environmental Sciences of the University of Virginia focused on questions regarding site
              hydrology and contamination of the site by organic compounds and by metals.


                      The major conclusions to come out of our study of the Cheatham Annex site follow.

                  1)  Any soluble subsurface contamination that is mobilized in the vicinity of the storage tanks,
                      the discarded drums, the cosmoline dump, and so forth will move down gradient in the
                      shallow groundwater and flow toward local streams and/or toward King's Creek and the
                      York River.

                  2)  No major areas of contamination, other than sediments of Hipps Pond, were discovered in
                      our study. There is large uncertainty, however, regarding the magnitude and extent of
                      undiscovered contamination of soils and groundwater. There is also great uncertainty
                      regarding the possible fate and transport of any contamination at the Cheatham Annex
                      site.

                  3)  Further work is required to

                      a) characterize the inflow and outflow of contaminated water in Hipps Pond during winter
                          and spring high-flow conditions;

                      b)  accurately determine the magnitude and extent of metals contamination at the site;

                      c)  assess the extent of the contamination of soils by organic contaminants and characterize
                          the soil/water partitioning of those organics; and

                      d) determine the rates of sediments in Hipps Pond and the biodegradation rates of
                          organic contaminants in the sediments.


                      The individual chapters of our report on site hydrology, contamination by organic
              compounds, and contamination by metals can be individually summarized.


                      The major points for summary from our hydrological study of the Cheatham Annex site
              follow.

                  1)  The major input of water to Hipps Pond is the base flow of streams. This base flow is
                      derived from the drainage of shallow groundwater that provides seepage inflow to streams.

                  2)  Summer stormflow originates from narrow riparian zones. Spring and winter stormflows
                      may originate from more laterally extensive surface and subsurface source areas. During
                      wet periods, the combination of storm flow and direct precipitation on the lake surface is a
                      significant component of the water budget of Hipps Pond.

                  3)  Groundwater gradients are very low; the sediments at the site are quite permeable. The
                      hydraulic gradients indicate that groundwater flow is generally toward the southeast,
                      toward King's Creek and the York River.









                   The major points for summary from our study of the organic contamination at the
             Cheatham Annex site follow.

                1) There is not much organic contamination present at Cheatham Annex except in the
                   sediments of Hipps Pond. This contamination may be due to oil spills in 1977 and 1978. It
                   is possible that additional contamination may be trapped by the sediments following high
                   discharge events into the Pond.


                   The major points for summary from our study of the metals contamination of the
             Cheatham Annex site follow.

                1) Because of deficiencies in the studies to date, the extent and magnitude of metals
                   contamination is unknown.









                                              TABLE OF CONTENTS



             I. INTRODUCTION                                                                    1
                    IA. Overall Question                                                        1
                    IB. General Site Description                                                2

             II.HYDROLOGY                                                                       5
                    IIIA. Introduction                                                          5
                    IIB. Site Description                                                       5
                            Hipps Pond                                                          5
                            North Branch Hipps Creek                                            6
                    IiC. Field Methods                                                          7
                            North Branch                                                        7
                                    Instrumentation                                             7
                                    In-stream Dilution Gaging                                   8
                                    Water Conductivity and pH                                   9
                            Hipps Pond                                                          9
                                    Instrumentation                                             9
                                    Pond Volume/Area Estimates                                  11
                            Hydraulic Conductivity Estimates                                    11
                            Instrument and Topographical Survey                                 12
                    IID. Analysis                                                               12
                            North Branch                                                        12
                                    Base Flow: Inflow Sources                                   12
                                    Base Flow: Longitudinal Discharge Rates                     14
                                    Storm Flow: Source Areas                                    15
                                    Storm Flow: Total Storm Volumes                             16
                            Hipps Pond                                                          17
                                    Area and Volume Calculations                                17
                                    Base Flow                                                   18
                                    Storm Fluxes                                                19
                                    Monthly Water Budget                                        20
                                    Residence Times                                             21
                    IIE. Results                                                                22
                            North Branch                                                        22
                                    Base flow                                                   22
                                    Storm Flow                                                  23
                            Hipps Pond                                                          24
                                    Monthly Water Budget                                        24
                                    Water Residence Times                                       25
                    IIF. Discussion                                                             25
                    IIG. Summary                                                                27

             III. ORGANICS                                                                      55
                    IIIA. Introduction                                                          55
                    IIIB. Methods                                                               55
                            Collection of Samples for Organic Analysis                          55
                                    Water Samples                                               56
                                    Sediment Samples                                            56
                            Laboratory Methods                                                  57
                    IIIC. Results                                                               59
                    IIID. Discussion                                                            61
                    IIIE. Summary                                                               63










              IV. METALS                                                                        74
                     IVA. Introduction                                                          74
                     IVB. Methods                                                               75
                            Sampling Philosophy                                                 75
                            Collection of Samples for Metals Analysis                           76
                                    Water Samples                                               76
                                    Sediment Samples                                            77
                            Analysis                                                            77
                     IVC. Results                                                               78
                     IVD. Discussion                                                            78
                     IVE. Summary                                                               80

              V. DISCUSSION                                                                     87

              VI. CONCLUSIONS AND RECOMMENDATIONS                                               90

              VII. REFERENCES                                                                   91

              VIII. APPENDICES                                                                  92
              Appendix I. Nature of Samples                                                     92
              Appendix 2. Water Level Measurements - UVA Wells                                  94
              Appendix 3. Water Level Measurements - ESI Wells                                  99



































10









                                                                LIST OF TABLES



                  2.1.   Soil descriptions from well boring logs                                                        28
                  2.2.   Conductivity and pH measurements, the North Branch                                             29
                  2.3.   Storm events during field season                                                               30
                  2.4.   Summary of University of Virgina field instrumentation                                         31
                  2.5.   Summary of head differences among nested piezometers, North Branch                             32
                  2.6.   Stream lengths and drainage sub-areas delineated for inflow estimates to
                         Hipps Pond                                                                                     33
                  2.6a. Drainage area IDs referred to in Table 2.6                                                      34
                  2.7. Summary of stream dilution gaging results                                                        35
                  2.8. Inflow rates for the North Branch                                                                36
                  2.9.   Summary of groundwater gradients                                                               37
                  2.10. Estimated groundwater inflows to the North Branch                                               38
                  2.11. Monthly water budget on Hipps Pond                                                              39
                  2.12. Contributions of water budget components of Hipps Pond                                          40
                  2.13. Fluxes of major components into Hipps Pond                                                      41
                  2.14. Estimated uncertainties in monthly water budget components of Hipps Pond                        42

                  3.1.   Information on the nature of the samples collected for organic analysis                        64
                  3.2.   Polynuclear aromatic hydrocarbons analyzed                                                     65
                  3.3.   Results for organic analyses of sediment samples                                               66
                  3.4.   Results of organic analyses of sediment samples                                                67
                  3.5.   Results of organic analyses of solid fraction filtered from water samples                      68
                  3.6.   Results of organic analyses of water samples                                                   69
                  3.7.   Results of organic analyses of water samples                                                   70
                  3.8.   Results of organic analyses of water samples                                                   71
                  3.9.   Results of organic analyses of water samples                                                   72

                  4.1.   Summary of metals analyses reported by ESI (1989)                                              81
                  4.2.   Information on the nature of the samples collected for metals analyses                         82
                  4.3.   Results of metals analyses                                                                     83
                  4.4.   Summary of detected metals                                                                     84









                                                             LIST OF FIGURES


                 1. 1. Generalized site map                                                                           4

                 2.1.  Generalized site map                                                                           43
                 2.2.  Detailed map of the southern drainage area of Hipps Pond showing
                       instrument locations                                                                           44
                 2.3.  Detailed map of the North and South Branches of Hipps Creek showing
                       station and instrument locations                                                               45
                 2.4.  Floodplain areas of the North Branch Hipps Creek                                               46
                 2.5.  Bathymetric map of Hipps Pond                                                                  47
                 2.6.  Pond response to a storm event                                                                 48
                 2.7.  Comparison of response traces during and following a storm event                               49
                 2.8.  Daily temperature cycles over a 4-day period                                                   50
                 2.9.  North Branch responses to three storm events                                                   51
                 2.10. Subsurface responses near the North Branch to three storm events                               52
                 2.11. Runoff yields from the North Branch floodplain above the flume for a
                       series of storms                                                                               53
                 2.12. Water levels records from well UVAPZ-1 during a series of storms                               54

                 3.1. Sampling locations for organics                                                                 73

                 4.1. Hipps Pond sampling locations for metals                                                        85
                 4.2. North and South Branch Hipps Creek sampling locations for metals                                86









                                                  1. INTRODUCTION


                                                   IA. Overall Question


                     The Commonwealth of Virginia Emergency Fuel Storage Facility (CVEFSF), herein

              referred to as the Cheatham Annex site, is a former Navy fuel supply depot currently

              administered by the Department of Emergency Services of the Commonwealth of Virginia.

              During its period of operation since its construction in the 1940's, various grades of fuel were

              stored and distributed at the site. Acquired by the Commonwealth in 1980, operations at the

              facility were ceased in 1982, at which time considerations were given to discerning the nature and

              extent of contamination.

                     A preliminary site investigation was conducted by the Department of Waste Management

              (DWM) in December, 1986. A private consulting firm, Engineering Sciences Incorporated (ESI),

              was contracted by DWM to further assess the status of contamination at the site and draft a set of

              potential remediation strategies. In June 1989, ESI submitted a preliminary report (ESI, 1989) of

              their findings. Their report left several unresolved questions concerning the potential for

              contaminants to move throughout the site.

                      In April of 1990, the Department of Environmental Sciences at The University of

              Virginia was contracted to continue research on the site. Although the potential of contam     inant

              migration cannot be completely characterized in even the most extensive investigation, the

              purpose of our research at Cheatham Annex was to evaluate the hydrological factors which may

              be important in contamination transport. Furthermore, we attempted to provide a preliminary

              characterization of organic and heavy metal contamination in areas believed to be sensitive or

              indicative of the general status of the site as a whole.

                     Although the likelihood of off-site transport cannot be inferred from our assessment,

              general conclusions can be drawn about the current state of contamination in hydrologically-

              significant areas of the site. Our overall research framework at the site was centered around the.

              following objectives:







                          1) assess groundwater-stream interactions on the North Branch Hipps Creek;

                          2) characterize the hydrology of Hipps Pond;
                          3) assess organic contamination of Hipps Pond and on the southeast margin of the

                              site;

                          4) evaluate heavy-metal contamination in surface waters and groundwater in an area

                              along the North Branch Hipps Creek.
               Our research design was to first characterize the hydrology of the site and integrate the important

               hydrologic factors into the chemical framework established from organic and heavy metal

               analyses.


                                                113. General Site Description


                      Cheatham Annex is located in York County, Virginia, approximately two miles from the

               York River. The 435 acre site (Figure 1.1) is bounded by Virginia State Highway on the northwest

               and the Colonial Parkway on the northeast. To the south and southeast, King's Creek and a

               contributing tributary form the site boundaries.

                      The Cheatham Annex site has a healthy flora and fauna distribution. Clear-cut areas are

               overgrown with grasses and shrubs while most of the site is forested with mixed pine and

               hardwood stands. These are populated by various woodland animals and birds. A number of

               small streams and a pond are inhabited by both fish and other aquatic species.

                      The site lies within the Coastal Plain physiographic province, typified by disconformable

               sequences of alluvial and transgressive-regressive marine sediments. In the higher elevations of

               the site, relatively flat grasslands grade into several entrenched valleys supporting hardwood

               stands of trees. The site is well drained by a network of incised perennial and ephemeral streams

               which flow into an artificial pond near the eastern boundary. Hipps Pond lies at the lowest

               elevation of the site, nearly 80 feet below the headwater regions of the upland contributing areas.

                      Various fuel storage and distribution structures are distributed around the site, the most

               conspicuous of which are 23 2.5 million gallon storage tanks. Eighteen tanks are concrete and


                                                                2








             completely below grade. The remaining five are of steel construction and are partially buried. The

             fuels distribution network for these tanks also includes valve boxes, oil/water separators, and

             pipelines located throughout the site.




      Figure 1.1.           CHEATHAM ANNEX
                                  SITE MAP



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                                                             (V.4
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                                                        CHEATHAM ANNEX PROJECT
                                                   Department of Environmental Sciences
              (Takon from: ESI, 1989)                     University of Virginia
                                                            December 1, 1990









                                                  11. HYDROLOGY


                                                   11 A. Introduction


                    The strategy of our hydrological research at the Cheatham Annex site was to identify the
             major factors which may play a role in the potential for contaminant migration within the site.
             We concentrated our efforts on groundwater-stream interactions in the North Branch Hipps

             Creek and the water fluxes into and out of Hipps Pond. We sought to first understand the

             dynamics of groundwater inflows to the North Branch because of the dominance of surface water

             drainage at the site. We examined groundwater input to the North Branch over three major

             periods: during storm events, over extended base-flow periods, and over monthly intervals. The

             overall purpose of the North Branch research was to develop relationships to estimate the

             surface water and groundwater contributions to Hipps Pond.

                    The motivation for the design of our field experimentation for an understanding of the

             hydrology of Hipps Pond stems from the expected salient control of the Pond over nearly all

             surface-derived water entering the site. Situated at the lowest point at Cheatham Annex, Hipps

             Pond drains nearly 75% of the site's surface area and thereby serves as the final reservoir for

             most of the water before leaving the site. Our primary objective was to identify the sources of

             water entering the North Branch under different conditions and to extend those interpretations to

             appraise the relative importance of all inputs and outputs to Hipps Pond.


                                                  IIB. Site Description


                                                       Hipps Pond


                     Hipps Pond is located near the central eastern margin of the site, and is bounded by an

             artificial berm and dam on its inflow and outflow ends, respectively. Three streams contribute

             surface water inflows to the pond: the North and South branches of Hipps creek, and a "marsh"

             creek directly entering Hipps Pond (Figure 2.1). Surface water leaves the pond through a
             standpipe which empties into a discharge stream. Direct groundwater inflows to the pond are

                                                              5









              derived from two major drainage areas to the south and north of the pond. On the north side, the
              perimeter road approximates the surface water drainage divide, whereas on the south side, the
              divide extends up to Diesel Drive (Figure 2.1). Both drainage areas are comprised of relatively

              gentle slopes covered with stands of hardwood trees.
                      In order to investigate direct groundwater inflows to Hipps Pond, a region of the southern

              drainage area near the pond was selected for study (Figure 2.2). The south side was chosen

              because it drains a considerably larger area than the north side, and it includes several storage

              tanks within its boundaries.


                                                 North Branch Hipps Creek


                      The North Branch Hipps Creek (herein referred to as the North Branch) drains the

              largest area of the site, and is the longest tributary of Hipps Creek (Figure 2.1). The upper half of

              the stream is characterized by steep sideslopes, a relatively narrow floodplain , and an incised

              channel (Figure 2.3). The sideslopes directly intersect the banks of the channel in certain areas,

              whereas a moderate floodplain or terrace is present further downgradient. The channel and bank

              material consist of sands, silty sands, and organic debris.

                      In the lower reaches, the North Branch is moderately entrenched into a floodplain which

              is considerably wider than corresponding areas in the upper reaches. Most of the floodplain in

              this area is marshy, and towards the confluence with the South Branch, the creek bifurcates into

              several channels. The channel material and the deposits along the banks and floodplain become

               iltier in the downstream direction. The South Branch and the marsh creek (Figure 2.3) share

              similar attributes with the North Branch along their lengths. For our experimentation, we selected

              a region of the North Branch which was representative of the upper reaches of all creeks at the

              site.









                                                                 6













                                                       11C. Field Methods



                                                          North Branch



               Instrumentation


                       The design of our research on the North Branch was to assess the components of inflow to

               the stream and determine the relative magnitude of each. We employed three methods to provide

               estimates representative of total inflow, vertical inflow, and lateral inflow to the creek. Because

               the interaction between surface and subsurface water was of interest, we concentrated our field

               efforts on the near-stream areas of North Branch.

                       Base-flow and storm discharges were monitored with a Parshall flume (1 inch throat)

               equipped with a continuously-recording analog water-level recorder. The flume was installed near

               VP-14 (Figure 2.3), and was situated upstream of a minor rill in an area with a moderate

               floodplain and fairly small (0.5 m) banks. The flume was secured with reinforcing bar and grouted

               in place. An earthen dam was constructed upstream of the flume to create a small stilling pond.

                       In order to assess the vertical and lateral groundwater inflows to the North Branch, fifteen

               1.2 and 2.5 cm hand-augered observation wells were installed (Figure 2.3). Included in this

               network were three nests of two piezometers installed directly in the stream to measure vertical

               gradients into the stream bed. Wells along the banks and the sideslopes provided water levels for

               lateral gradients into the stream

                       The installation of all wells and piezometers began with a 2.5 to 5 cm boring to the desired

               depth of the instrument. After the instrument was placed in the hole, well sorted coarse sand was

               poured around the screened interval of the casing. The bore hole was then filled with a bentonite

               grout to seal the casing from the top of the screened interval to the ground surface.

                       Nearly all wells and piezometers were equipped with an inner acrylic tube filled with cork

               at the base to measure high water levels. The cork would rise with water levels during a storm,

               and adhere to the side of the acrylic after water levels receded. During a site visit, two water levels

                                                                  7









              were obtained: a current water-level and a high-water level corresponding to the most recent
              storm. So equipped, the water levels from the wells and tensiometers were used to examine water-

              level rises during storm events, and recovery times following.
                     The dominant sediment type encountered in the borings for hillslope and floodplain wells
              was a silty sand which included occasional interbeds of clayey silts and shells (Table 2.1). The
              water bearing unit for the site is the Yorktown formation (ESI, 1989), the top of which was
              exposed on the sideslopes upstream of the flume. Within the stream channel however, recently

              deposited well sorted sands were interbedded with prominent leaf and organic layers.

                     In addition to groundwater inflow estimates derived from lateral and vertical water-level

              gradients, vertical seepage into the stream channel bottom was measured directly with seepage

              meters. These instruments are identical in design to those used in a study at Lake Anna, Virginia

              (McIntyre, 1988). The meters are essentially a 30 cm section of 20 cm (ID) PVC pipe with a

              funnel affixed to the opening at one end of the pipe. They were installed to a depth of 30 to 35 cm

              by first excavating a hole, and driving the pipe to the depth at which the funnel top was equal in

              elevation with the stream channel bottom. All air was purged from the meters before a condom

              was attached to the end of the funnel. Over the course of a sample period, seepage water would

              enter the pipe and collect in the condom. The water volumes collected from these meters

              provided a direct estimate of vertical inflows in several locations along the North Branch, from

              which inflow rates per unit stream length were computed.


              In-stream Dilution Gaging


                     A final assessment of groundwater inflows was made by conducting an in-stream dilution

              gaging experiment. This field method was used to derive total inflow estimates for the North

              Branch along our study region. The principle of the experiment is based on mass balance. The

              injection inflow rate and concentration of a conservative tracer are related to observed

              downstream concentrations diluted by groundwater inflows.

                     An experiment was conducted on 16 May under base-flow conditions. A potassium

                                                               8









              bromide solution was introduced into the stream at rate of 3.85 mL/s from a location in the upper

              reaches of the North Branch (Figure 2.3). In-stream tracer concentrations were monitored at five
              sample stations positioned downstream of the injection point (Figure 2.3). The experiment
              continued until tracer concentrations at all sample locations stabilized over time. The observed

              concentrations were related to the tracer inflow rate and concentration to estimate the discharge

              at each sample location. Groundwater inflow rates between stations were computed by simply

              subtracting the calculated discharge at a station from the discharge at the next downstream

              station.



              Water Conductivity and pH


                      We completed our investigation of groundwater inflows to the North Branch by

              monitoring pH and conductivity at several locations along the length of the stream. We believed

              that significant inflows of "old" resident water might be represented by variability in either

              chemical parameter along a stre  tch of the creek. Measurements were taken from several riparian

              wells and also at ten in-stream sample locations (Figure 2.3; Table 2.2). No observable differences

              in these measurements were detected along the length of the North Branch or between surface

              water and groundwater.


                                                         Hipps Pond


              Instrumentation


                      The primary objective for our research on Hipps Pond was to examine all inflow and

              outflow water components. Surface water outflows, groundwater inflows, and pond level stage

              were monitored over the course of the study period.

                      Surface water discharges in the outfall stream were monitored with a Parshall flume (6

              inch throat) installed directly below the standpipe from Hipps Pond (Figure 2.2). Water levels

              were continuously monitored with an analog recorder. The flume was secured with reinforcing bar


                                                                9









               and grouted in place.

                       Changes in pond storage were determined from an in-pond meter staff and a water-level

               recorder. The recorder monitored water-levels continuously, which were related to observed

               heights from the meter staff. In addition, rainfall was continuously recorded by a weighing-bucket

               raingauge (Table 2.3).

                       A set of hand-augered wells (Table 2.1) was installed along a transect perpendicular to

               Hipps Pond (Figure 2.2). Water levels were continuously recorded in one of the wells, UVAPZ-1.

               In addition, two nests of piezometers were installed along the margin of the pond. Other wells

               were situated near existing ESI wells to establish directions of groundwater flow. In all wells, a

               sand pack was positioned around the screened interval and a grout slurry was poured above the

               sand to the soil surface. The slurry was used to bind the well casing to the soil to inhibit rainwater

               from traveling down the casing into the subsurface. In piezometers, the grout slurry extended

               from the top of the screened interval to the soil surface.

                       A nest of tensiometers (Table 2.4) was installed near piezometer nest UVALP1/LP2 and

               tied into the transect of wells upslope (Figure 2.2). In addition to monitoring soil moisture, one of

               the four tensiometers recorded pond level and served as a reference for removing temperature

               beases in the digital records from the other tensiometers (Hoelscher et al., in revision). All

               tensiometers were equipped with pressure transducers. The millivolt output from the transducers

               was recorded by a data logger which also collected ambient air temperature at ten minute

               intervals. This nest of instruments was located at the downslope end of a major draw. We

               suspected that the draw might be a major groundwater flowpath during storm events.

                       During borings for well installations, soil types were visually identified and recorded in
               field logs (Table 2.1). The predominant sediment types on the contributing slopes of Hipps Pond
               were medium grained silty sands to very clean homogeneous sands. Interbeds of clay and shell
               material were encountered in several well borings. A moderate to strong petroleum odor was

               present in nearly all well sediments.




                                                                  10










              Pond Volume/Area Eslimales


                      The bathymetry of Hipps Pond was determined from a total of twelve transects across the

              Pond. Transects were taken across the narrow width of the pond from a base line along the

              southern bank at 30-m intervals. Water depth measurements were taken along each transect at

              7.5-m intervals. The measurement sites along each transect were more closely spaced than tran-

              sect intervals because of the greater expected variability across the bottom. Three additional

              transects were taken across the finger-like cove on the northeastern side of the lake. These data

              were used to construct a bathymetric map of the pond, from which the pond area and volume

              were determined.


                                             Hydraulic Conductivity Estimates


                      To complete our evaluation of groundwater inflow to the North Branch and Hipps Pond,

              two experiments were conducted to determine saturated hydraulic conductivities of hillslope soils.

              Slug tests were conducted on several occasions on wells NW-4, NW-3, NW-2 and NW-12 on the

              North Branch, and PZ-1 and PZ-4 near Hipps Pond (Figures 2.2 Figure 2.3). A PVC section with

              an attached manometer was fit directly onto the top of the well casings. Water was poured into

              the attached PVC until the water level in the manometer would reach a designated starting level.

              Water input was discontinued, and head levels in the manometer would be recorded at successive

              time intervals.

                      Direct measurements of hydraulic conductivity were not obtainable with this method. Two

              experimental difficulties disallowed completion of the experiments: either the input flow rate was

              inadequate to reach a constant level in the manometer, or the rate of head drop in the

              manometer was too rapid for water level observation. These difficulties were indicative of fairly

              high saturated hydraulic conductivities.

                      A second approach was undertaken in which potassium bromide was introduced into a

              well and monitored in a down-gradient well. A concentrated bromide solution was poured into








               well NW-3 which was installed on a north facing hillslope. Concentrations were monitored in well
               NW-12, approximately 4 m downslope of NW-3, for two days. During that interval, bromide
               concentrations in NW-12 did not significantly change. A similar experiment was conducted using

               UVA wells PZ-1 and PZ-2 on the south side of Hipps Pond. Bromide was not recovered in the

               down-gradient well (PZ-1), which is approximately 25 m from PZ-2. Both tracer tests suggested

               that either low gradients, low hydraulic conductivities (inconsistent with slug test results), or

               heterogeneous soils characterize the regions between test wells.

                      Although a direct estimate of hydraulic conductivity (K) was not obtained, we estimated a

               value based on published values (Freeze and Cherry, 1979) for similar deposits and direct

               observations of rapid drainage in the slug tests. For the hillslope sediments, we estimated a range
               of possible K values from     10-2 to 10-3 cm/s, which represents the upper end of hydraulic

               conductivities.


                                            Instrument and Topographical Survey


                       The locations and elevations of all UVA instruments were determined with a theotolite

               (Table 2.6). In addition, a topographical survey (Figure 2.2; Figure 2.3) was completed for the

               entire length of the North Branch (including local drainage areas), the mouth of the South

               Branch, and the "local" drainage area to the south of Hipps Pond. Elevation control points were

               established from several ESI wells adjacent to the North Branch and near Hipps Pond.


                                                         111). Analysis


                                                          North Branch



               Base Flow: Inflow Sources


                       Groundwater inflows to the North Branch were subdivided into three groups in our

               analysis: total, vertical and lateral. The control for assessing the relative proportion of each was

               established from the results of the dilution experiment. Direct measurements of vertical seepage


                                                                 12








              were obtained from the seepage meters, and water levels from wells and piezometers provided

              calculated estimates of both vertical and lateral inflow rates.

                      The results from the dilution experiment were used to derive an estimate of total
              groundwater inflow per unit stream length. Discharge gain over a length of stream was
              determined by simply subtracting the discharge at an upstream station from the successive
              downstream station. This gain was then expressed as an inflow rate per unit meter of stream by

              dividing the difference by the distance between stations.
                      Total inflow was then partitioned into lateral and vertical components. Lateral inflow was
              not directly measured, but estimated with Darcy's Law. Darcy's Law can be expressed in a finite

              difference formulation:

                                             Q = KA [h2-hl/L2-Ll]                                          (1)

              where

                              Q    volume discharge per time (L  3/T),
                              K    saturated hydraulic conductivity (I:-/T),
                              A    cross-sectional area (L 2),
                              hl-h2   head difference between two points,
                              Ll-L2    distance between points.

              This equation   relates the volume outflow across a unit area to the groundwater gradient and the

              saturated hydraulic conductivity.

                      All water levels were first expressed in terms of absolute elevation. For adjacent wells and

              wells near the creek, head differences were divided by the corresponding distance between points

              to estimate the gradient. The area was estimated by considering a unit meter length along the

              stream, and estimating the intersection of the water table with the stream to be 1 m. The 1 m

              width roughly corresponded to the channel width.
                      Two monitoring intervals were selected for gradient computations, one in the early part of

              the field season, and one in the late. These two intervals were also selected because water levels

              collected during those intervals were known to be reliable. Experimental problems arose with the

              acrylic tubes in the small diameter (1.25 cm) wells and piezometers. The emplacement of the

              tubing into the wells displaced considerable water, resulting in spuriously high "current" and "high"


                                                                 13








               water levels. Before the problem was corrected, "current" water levels were completely unreliable.
               This was clearly demonstrated by the high variability of water level differences among nested

               piezometers over several monitoring intervals (Table 2.5).
                       Because tests for K were not conclusive, a range of values from  10-2 to 10-3 cm/s was used
               as described in section IIC of this report. Lateral inflows to the creek were then calculated with

               these variables for two monitoring intervals.

                       Vertical seepage estimates were calculated using Darcy's Law as specified above. Three

               piezometer nests along the North branch provided potentiometric head readings from which

               gradients were computed. The largest unknown parameter in this application of Darcy's law was

               the hydraulic conductivity. Due to the presence of continuous layers of highly restrictive leaves

               and organic matter within the channel bottom sands, we reduced the range of possible

               conductivities by a factor of ten from the lateral inflow calculations. Two endpoints of
               conductivity, 10-3 and 104 cm/s, were used to calculate the vertical inflow rates.

                       These estimates were compared with direct measurements of vertical seepage from the

               seepage meters. Over certain intervals during the field season, a meter was installed near each

               piezometer nest. The measured inflow rates were calculated for a unit area having dimensions of

               1 m by 1 m, the same flux area used for the gradient-based values. Based on the discrepancies

               between the estimated and measured vertical seepage rates, the applicability of the estimated

               hydraulic conductivities was quantified.


               Base Flow: Longitudinal Discharge Rates


                       The proportion of lateral and vertical inflow to total inflow was extended to characterize

               groundwater inflows along the entire length of the North Branch, South Branch, and the marsh

               creek. Based on the results from the dilution experiments, we derived a relationship between the

               inflow rate and the corresponding contributing area along a reach of interest. The areas were

               estimated by extending perpendicular lines away from each creek segment considered in the

               dilution experiment. This inflow per unit area relationship was "calibrated" to consider spatial and


                                                                  14








              temporal changes in the factors affecting inflow rates.

                      Spatial variability was included in the inflow relationships through groundwater gradients

              and hydraulic conductivity. An "effective" reference groundwater gradient to the North Branch in

              the area of the dilution experiment provided an inflow estimate. The dilution-based estimate and

              gradient-based estimate were equated by using a value for the hydraulic conductivity which gave

              the same inflow rate as the dilution-based estimate.

                      Over other drainage areas, regions were delineated in which gradients different from the

              reference gradient (Table 2.6; Table 2.6a). The ratio of the observed gradient in another area and

              the reference gradient was used to adjust the inflow rate for the area of interest. In areas in which

              data were not available, the topography was used to estimate the gradient. This relationship was

              also used to estimate groundwater inflows in regions where hydraulic conductivities differed from

              values used in the North Branch study area.

                      Besides gradient and hydraulic conductivity, base-flow through the North Branch flume

              was included as a factor to adjust inflows for temporal changes. Base-flow at the location of the

              North Branch flume was approximated for the dilution experiment. Total inflows over base-flow

              periods were then scaled depending upon the observed discharges through the North Branch

              flume. The combination of all these factors was used to estimate total surface water contributions

              to Hipps Pond over base-flow periods.


              Storm Flow: Source Areas


                      The other important component of surface water/groundwater interactions is storm

              runoff. Significant volumes of water can be moved through a catchment during a storm. We

              sought to delineate the most active areas near the stream during storm events in an attempt to

              estimate total storm volumes into Hipps Pond.

                      To evaluate the source of storm-response discharges in the stream, high-water marks from

              wells were segregated by proximity to the stream. High-water marks also provided information

              about the potential for stream bank storage to occur during a storm. We believe that very steep


                                                                 15








              gradients immediately adjacent to the stream may temporarily "reverse" the gradient upslope and

              change stream bank storage. After passage of the hydrograph peak, extended recession limbs

              might result from this considerable storage. Storm hydrographs were the fundamental unit of

              observation for our analysis of storm flows in the North Branch. Storm volumes through the

              North Branch flume were determined by integrating the area under the hydrographs.

                     During the course of the summer, several storm responses were not recorded due to the

              timing of intervals for instrument operation. Typically, the only data available were pre-storm

              discharge, peak discharge, and discharge during a field visit. Based on the unit hydrograph

              concept, we devised a method to estimate the storm volumes corresponding to the observed peak

              discharges. Our main assumption was that the relationship between the peak discharge and the

              total storm volume remained constant. By doing so, we did not restrict ourselves to the

              assumption that storm "yield" or excess rain at the site was constant over all storms.

                     A ten minute unit hydrograph was created from a hydrograph following an "average"

              rainfall. The storm volume was calculated by removing baseflow and scaling the hydrograph with

              the ratio of the observed rainfall to a 1 cm rainfall. Storm volumes from missing hydrographs were

              estimated by multiplying the unit hydrograph by an appropriate rainfall which yielded the

              observed peak discharge. This method did not account for differences in observed rainfall values;

              it simply related observed peak discharges to corresponding storm volumes based on a constant

              relationship between the two.


              Storm Flow: Total Storm Volumes


                     It is generally acknowledged that groundwater does not play a significant role during

              storm events in upland forested catchments (Cherry, 1974; Kolla, 1987). Based on the high-level

              marks in the wells, we determined the active areas contributing to storm flow. Our overall interest

              was to determine the total storm volumes from all creeks into Hipps Pond.

                     The floodplain area was selected as the main contributing area during storms. The

              observed storm volumes through the North Branch flume were expressed as a flux across the


                                                                16








              upstream floodplain area of the flume. Floodplain areas were delineated on the North Branch,

              the South Branch (Figure 2.4), and the marsh creek. For each storm, the flux derived from the

              North Branch flume data was applied to all downstream floodplain areas on the North Branch,

              South Branch, and the marsh creek. The main assumption of this methodology was that storm

              yield in the upper reaches of the North Branch was representative of the entire length of each

              creek.


                                                         Hipps Pond


                     Our analysis of the hydrology of Hipps Pond was subdivided into base-flow and storm-

              related periods. The relative importance of all components was appraised under these different

              conditions. The final analysis of Hipps Pond was extended to a monthly time scale to consider the

              changes in the proportions of each component over seasonal periods.


              Area and Volume Calculations


                     Values for pond surface area and total water volume were instrumental in the water

              budget calculations. Surface area was calculated graphically using a scaled map of the pond. This
              plan was gridded into 1 m  2 sections. The total area of the pond was calculated by summing all

              sections included within the pond boundaries. The total area was calculated to be approximately

                       2
              25,400 m .

                     In order to calculate the volume of Hipps Pond, a depth profile from our field survey was

              created. The original data were horizontally adjusted to align all transects along a common grid

              axis. This information was used to create a bathymetric map (Figure 2.5).

                     A volume integration routine was also used to calculate the pond volume. We were not

              able to force the program to recognize the boundary points of the pond, which led to initial over-

              estimations of the pond volume. This problem was circumvented by calculating the volumes

              corresponding to each contoured area of depth. An approximate lake volume was derived by

                                                                                                3
              summing these contoured areas. This method provided an estimate of 45,000 m , which roughly


                                                               17









             agreed with the volume corresponding to an average pond depth of 1.5 m.


             Base Flow


                     The two major inputs to Hipps Pond during base-flow (or inter-storm) conditions were

             surface water inflow and direct groundwater inflow. The inflow relationship among groundwater

             inflow rates, hydraulic conductivity, and groundwater gradients was used to estimate the total

             surface water inflow to Hipps Pond. This relationship was extended to estimate direct ground-

             Water inflows.

                     For direct groundwater inflows, two major variables of the relationship differed from

             those used in surface water inflow calculations on the North Branch: the cross-sectional area

             across which groundwater entered the pond, and the hydraulic conductivities. The cross-sectional

             area (or flux plane) was estimated from our pond bathymetry analyses. A conservative value of 1.5

             meters was chosen as the width (or depth) of the plane. The drainage area on the south side was

             subdivided into two regions based on the differences between observed gradients. The straight-

             line distances along the shore of each subdivided region provided the length of the flux plane for

             each drainage area.

                     Although the hillslope sediment in each subregion was nearly identical to hillslope

             sediments on the North Branch, the pond bottom sediments ultimately controlled inflow rates to

             the pond. The predominant lake sediment type was a sandy clay, overlain by an organic rich silty

             clay. Based on published figures (Freeze and Cherry, 1979) we estimated the hydraulic
             conductivity of the material to be 10-4 cm/s. The total groundwater inflows were computed with

             these variables for the north and south sides of the pond.

                     The output components roughly correspond to the sum of the surface water and

             groundwater inflows to the pond. Perhaps the most important was the pond discharge through
             the outfall stream. Discharge data from the outfall flume were integrated over base-flow periods

             to estimate total base-flow output volumes.

                     During the summer, the other important output component was evaporation from


                                                              18








             the lake surface. We selected the Hamon method (Hamon, 1961) for estimating potential

             evapo-transpiration (PET) because the only input requirements were latitude and daily

             average temperature. It has been shown to yield comparable values with those from more

             detailed and sophisticated methods (Hamon, 1961). We made a preliminary test of this

             observation by comparing estimates from the Hamon method with those from the Priestly-

             Taylor method. The data came from a fresh-water marsh at approximately the same

             latitude as the Cheatham Annex site. We could not identify a significant bias in the Hamon

             method estimates. Estimates for the pond PET were calculated from daily averages of

             temperature readings collected by the data logger.

                    Seepage through the dam at the outflow end was also estimated. Although no data

             were directly available to make the calculations, gradients were estimated, and the

             hydraulic conductivity for the pond sediments was used.

                    Pond storage changes were also computed for the base-flow intervals. Daily pond

             level for each interval were computed by subtracting the end pond level from the starting

             level, and dividing by the time interval. All components of the base-flow intervals were

             expressed in terms of flux across the pond area per day.


             Storm Fluxes


                    Our primary objective for examining storm responses in Hipps Pond was to

             compare the relative contributions of the two major inputs: direct rainfall on the pond aquifer

             surface and surface storm  flows. We were also interested in the relative changes of each input

             component across different storms, and possible groundwater bulging at the lake margin during

             storms.

                    In order to estimate the components of lake responses during a storm event, we

             established a time reference with the lake level hydrograph. Clearly, the total duration of

             surface water runoff can not be accurately estimated from discharge data in the headwater

             regions on the North Branch. We did however, have good temporal control on rainfall duration,


                                                              19








              lake level responses, and lake discharge.

                      Our analysis of storm events focused on two intervals represented in nearly an lake

              hydrographs. The first interval comprised the initial lake level response to nearly constant peak

              levels (Figure 2.6). We assumed that all rain fell during that interval, and surface runoff was

              initiated into the creeks. The second interval was defined by the steady-state pond levels

              following nearly all storms. With no storage change, inflow rates equal outflow rates. During these

              intervals, PET was assumed to be zero. Hence, the only active components were surface water

              input, lake discharge and storage changes. Because the latter two components could be estimated

              with some certainty, the dependability of the calculated surface water inputs could be assessed.

                      We also sought to evaluate the buildup of groundwater gradients at the pond margin from

              the tensiometer records of soil water pressure. Although we had hoped to establish a control for

              removing temperature biases in the digital output from the transducers, each transducer behaved

              differently in response to thermal and solar loading. These thermal and solar factors were found

              to exert more control on the output than actual changes in soil water/lake level pressure changes

              (Figure 2.7). The large excursions in the output followed quite closely the ambient air

              temperature fluctuations (Figure 2.8). The variability of transducer output with respect to

              environmental factors was too great for accurate reconstructions of soil pressure gradients to be

              made.



              Monthly Water Budget


                      Our overall assessment of the hydrology of Hipps Pond focused on monthly water

              budget calculations. Monthly averages were computed for surface water base flow,

              groundwater inflow, dam seepage, PET, and storage changes. Total surface water storm

              volumes were also calculated. Total pond discharge volumes were computed by integrating

              under the monthly time-series discharge records from the outfall flume.

                      A crucial aspect of the monthly water budget was the error associated with each

              component. In part, the base-flow and storm event analyses provided a starting point for


                                                                20








             assessing the magnitude of each error component because of the control on certain components.

             Although straightforward methodology does not exist for estimating errors in each, we followed

             the error analysis in Winter (1981) to approximate probable uncertainties.

                    Clearly, our surface water estimates represent one of the highest uncertainties on

             the monthly time-scale. The major source of error for surface inflow estimates is the

             assumed constancy of inflow rates over space. Although we accounted for gradient

             changes, we do not have any direct way of verifying these estimates other than comparison

             with other nearby catchments. As a crude approximation to an error estimate, we calculated

             discharge per unit area from several gaged catchments of various sizes on the coastal plain of

             Virginia. The variability of values for several months was used as an indication of the likely

             uncertainty in our inflow estimates.


             Residence Times


                    Our final characterization of the role of Hipps Pond in mediating inputs and

             outputs from the site was established by calculating mean water residence times. Over the

             course of the three month study period, total inputs were assumed to equal total outputs

             with no net change in lake storage. The mean residence time (T) of a parcel of water can

             be computed with


                                          T = V/R                                                   (2)
             where          V = pond volume,
                            R = steady inflow/outflow rate.












                                                            21











                                                        11E. Results



                                                       North Branch



             Base flow


                     The results from the dilution experiments indicate that groundwater inflows to the North

             Branch are fairly constant along the study reach (Table 2.7). Expressed in terms of inflow per unit
             drainage area, all inflow estimates are nearly equal, ranging from 1.9 x 10-5 to 2.2 x 10-5 L/m2s.

                     Vertical seepage measurements were variable along the study reach but fairly constant at

             each location (Table 2.8). Observed seepage rates did not appear to be related to observed

             gradients in nearby piezometer nests (Table 2.9). It is likely that the restrictive leaf layers are

             laterally discontinuous resulting in varying vertical hydraulic conductivities of the channel

             material along the North Branch.

                     Groundwater gradients generally increased with proximity to the stream (Table 2.9).

             Lateral gradients do not significantly vary however, but are generally much lower than vertical

             gradients in the creek channel. Based on the observed gradients, the "effective" lateral gradient

             into the North Branch in the study area is 0.042. which represents an average of all observed

             gradients.

                     Lateral inflows to the creek comprise the largest percentage of total groundwater inflows
             to the creek (Table 2.10). The highest measured vertical seepage rate (5.7 x     10-3 cm/s) at nest

             UVANW-6/NW-7 is lower than the total measured seepage by over a factor of one hundred.
             Based on the dominance of lateral inflows to the creek, a hydraulic conductivity of 1.5 x 10-2 CM/S

             corresponds to an observed gradient of 0.042 and a flume discharge of 4.0 L/s. These variables

             are directly related to the inflow per unit drainage area (Table 2.7) determined from the dilution

             experiment.

                     The importance of lateral inflows during base-flow conditions confirms field

             observations of considerable seepage from bank faces and sideslope bases. On several


                                                               22








               occasions, test pits excavated into the banks quickly filled with water. These results indicate that a

               relatively small vertical section of the water bearing formation (Yorktown) intersects the North

               Branch.

                       The considerable storage of the Yorktown is further demonstrated by fairly constant base-

               flow discharges through the North Branch flume over the course of the summer. Furthermore,

               groundwater gradients did not significantly decrease among most wells (Table 2.9). Only in early

               October, following an extended period (1.5 months) of rainless weather, did water cease to flow

               through the flume. At that time however, surface water flow was present approximately 100 m

               from the flume.



               Storm Flow


                       Storm hydrographs through the North Branch flume indicate that the creek responds very

               rapidly to storm events. Typically, peak discharges occur approximately 30 to 60 minutes following

               the onset of rain (Figure 2.9). Most storms during the study period were however, very severe and

               of high intensity (Table 2.3). The descending limbs of the North Branch hydrographs represent

               fairly rapid returns to near-base-flow discharges, which suggests that bank storage is not

               significant. In nearly all hydrographs, base flow conditions were established approximately 12 to

               18 hours after the passage of the peak discharge.

                       The major areas of storm water contributions appear to be limited to the near-

               stream, or riparian areas. Over several storms, water level responses were high in all near-stream

               wells (Figure 2.10). The water levels of the deeper wells far from the North Branch were largely

               unaffected by all storms over the summer field season. Considering the steep sideslopes on all

               creeks at the site, it is likely that storm responses are largely limited to the floodplain areas.

                       Storm volumes expressed as fluxes across the floodplain area above the North Branch

               suggest that storm yield was not highly variable (Figure 2.11). The sediments of hillslopes bases

               and the floodplain drain rapidly and most likely return to pre-storm conditions within two days.




                                                                  23









                                                        Hipps Pond


             Monthly Water Budget


                     Over the course of the study period, the primary input to Hipps Pond is surface water

             under base-flow conditions (Table 2.11). Direct groundwater inflows are negligible compared to

             monthly surface water inputs. During the wet months of July and August, total storm water
             volumes (surface and direct rainfall) were nearly as high as base-flow inputs. During the drier

             month of September however, base-flow is the predominant inflow component to the Pond.

                     The outputs from the pond were nearly evenly distributed between PET and pond

             discharge. The importance of PET lessens during September, particularly during distinct base-

             flow periods (Table 2.12), but still represents a significant proportion of the outflow from the

             pond.

                     During individual storms, direct rainwater inputs are slightly greater than surface water

             runoff (Table 2.13). The importance of surface runoff and direct rainfall over groundwater inputs

             during storms is well demonstrated by very minor responses in well PZ-1 during very intense

             rainstorms (Figure 2.12).

                     Although our results demonstrate the importance of base-flow inputs, and PET and

             lake discharge outputs, consideration of the errors involved with each estimate suggests

             that PET and total surface water inputs contained the largest degrees of uncertainty (Table 2.15).
             Calculations of surface water discharges from several gaged stations yielded a mean of 6.9 x 10-5
             L/M2   s, with an average standard deviation of 3.2 x  10-5 L/M2 s. These results suggest that the

             variability of the inflow rates may be 100 %.

                     Our own results suggest that the uncertainty may be biased in the negative direction, i.e.

             surface water inflows - including storm runoff -are underestimated (Tables 2.12 and 2.13). It is

             likely that the negative residuals for inter-storm periods (Table 2.12) results from a combination

             of overestimating PET and underestimating surface water inflows.

                     It is also quite probable that both groundwater inflows and dam seepage are

                                                               24










              underestimated. Although their contributions to the overall budget remains minimal, it is

              important to consider the offsetting effects of each estimate. Both flux rates are fairly constant

              through the seasons because each component intersects a fairly wide flux area. Furthermore, the

              gradients driving each component would not significantly change over time. Hence, although each

              may be underestimated, their combined importance would probably be negligible. Upon

              consideration of all errors, we believe that the -relative proportions of each component to the

              overall budget would not significantly change.


              Water Residence Times


                     Based on average total outflows from the pond over the study period, the average

              residence time of water in the pond is approximately 7 months. During the fall and winter

              months as rainfall and PET drop, net input and output rates would drop, resulting in

              higher net residence times. During the spring however, as recharge occurs and inflows

              increase, the net residence time would probably increase. Considering the total volume of

              water moved through the pond during the summer months, it is likely that 7 months represents

              the average residence time on a yearly basis.


                                                      11F. Discussion


                     Because hydrology is the driving force behind contaminant migration, it is necessary to

              consider not only the relative proportions of water entering Hipps Pond, but the source and the

              chemistry of the water. Base-flow is the largest input component to Hipps Pond and represents

              water from approximately 75% of the site. In a pure hydrological interpretation, the majority of

              dissolved and suspended contaminants would enter the pond under base-flow conditions.

              Furthermore, because the hazardous material storage drums identified by ESI are located within

              the largest drainage areas, potentially contaminated groundwater from these areas would not be

              considerably diluted with relatively "clean" groundwater in the creeks.

                     The migration of contaminants may become slightly higher in spring months as gradients

                                                               25









              increase and inflow rates increase accordingly. Furthermore, increased contaminant inputs to the

              pond during spring months would not proportionally increase the pond contaminant

              concentration due to direct rainfall onto the pond surface and perhaps cleaner storm flow water.

              Upon reaching Hipps Pond, pond water residence times are long enough to allow for possible

              physical and chemical processes to occur which may reduce contaminant concentrations at the

              pond outflow.

                     If chemical factors were associated with the ability of contaminants to move, contaminants

              may tend to accumulate near or in the floodplain sediments. Our results indicate that the bulk of

              storm water is derived from the floodplain areas, suggesting that "spike" inputs of contaminants

              would be associated with storm events. Considerable water is moved through the pond during

              these events, which would represent the greatest potential for dissolved and suspended

              contaminants to move through the pond over the shortest time interval. Although storm volumes

              on a monthly basis are hydrologically less important than base-flow inputs, they may represent the

              most important chemical pathway for contaminant migration to the pond.

                      In summary, our hydrological research on the North Branch Hipps Creek and Hipps Pond

              suggests the overall control of base-flow on the hydrology of Hipps Pond. Highly conductive soils

              and very low groundwater gradients sustain the creeks through extended dry periods although

              significant recharge does not occur in the summer months. Although of slightly lesser importance

              on a monthly basis, surface storm responses are extremely rapid and mobilize considerable

              volumes of near-stream riparian groundwater. Direct groundwater contribution into the pond is

              relatively insignificant mainly due to the low conductivities of the lake bottom sediments. During

              the summer months, outputs are evenly distributed between evaporation and pond discharge. On

              a yearly basis, surface base-flow and lake discharge are the largest overall components of the pond

              hydrology.







                                                                26








                                                       IIG. Summary


                     The major points for summary from our hydrological study of the Cheatham Annex site

             follow.

                 1)  The major input of water to Hipps Pond is the base flow of streams. This base flow is

                     derived from the drainage of shallow groundwater that provides seepage inflow to streams.

                 2)  Summer stormflow originates from narrow riparian zones. Spring and winter stormflows

                     may originate from more laterally extensive surface and subsurface source areas. During

                     wet periods, the combination of storm flow and direct precipitation on the lake surface is a

                     significant component of the water budget of Hipps Pond.

                 3)  Groundwater gradients are very low; the sediments at the site are quite permeable. The

                     hydraulic gradients indicate that groundwater flow is generally toward the southeast,

                     toward King's Creek and the York River.





























                                                               27










                Table 2. 1. Soil descriptions from well boring logs. For locations of wells, refer to Figure 2.3.

                Location          Depth              Description
                                  interval
                                    (m)


                UVA_PZ1           0.00-0-91          Fine sandy silt, moist,brown
                                  0.91-1.52          Fine silty sand, wet,brown,water at 1.28
                                  1.52-2.53          Fine well sorted sand,trace silt, wet

                UVAPZ2            0.00-0.85          Fine to medium silty sand,moist,
                                                        brown to red-brown
                                  0.85-1.16          Fine sand,trace silt,moist,tan
                                  1.16-1.62          Fine silty clayey sand,moist,
                                                        slightly cohesive and mottled
                                  1.62-2.53          Sandy lean clay,trace gravel,moist
                                                        gay and brown
                                  2.53-2.83          Silty clay,moist,mottled,brown
                                  2.83-3.81          Coarse sandy clay, moist,brown
                                  3.81-4.88          Coarse clayey sand,wet,saturated at 3.96m,
                                                        contains shell fragments at 4.88m

                UVAPZ3            0.00-1.37          Fine sand with silt,moist,brown
                                  1.37-3.05          Fine sand with clay,moist,brown
                                  3.05-5.18          Fine to medium clayey sand,mottled,brown
                                  5.18-6.71          Fine to medium silty sand,wet, contains
                                                        shell fragments; saturated at 5.18

                UVANW3            0.00-1.16          Fine sandy silt,moist
                                  1.16-1.83          Silty clay,moist, consolidated
                                  1.83-2.19          Fine to coarse clayey sandy gravel,
                                                        wet; saturated at 1.83

                UVANW4            0.00-1.28          Sandy silt with clay, moist,consolidated
                                  1.28-1.52          Fine sandy clay (CL),saturated,blue-gay

                UVANW5            0.00-1.52          Fine well sorted sand,silty, moist,brown
                                  1.52-1.83          Silty clay with sand,moist,consolidated,
                                                        mottled,brown
                                  1.83-2.44          Sandy gravel with clay,wet,yeHow-brown

                General observations for groups of wells:

                UVANW1/NW2, UVANW6/NW7, UVANW8/NW9: Well sorted medium gained sands with silt
                        and gavel; contains lenses of leaves and organic material

                UVALPl/LP2, UVALP3, UVALP4/LP5: Sandy silty clay with peat and organic silt; saturated;
                        strong odor of petroleum product





                                                                     28









                Table 2.2. Conductivity and pH measurements of surface water and groundwater in the North
                Branch and adjacent wells, respectively. Measurements were taken on 21 June, 1990 during a base
                flow period. For locations of wells and sampling stations, refer to Figure 2.3.

                Sample location                            pH                                Conductivity
                                                                                             (AS/cm)


                Groundwater


                     UVANW-6                               7.0-7.5                                  600
                     UVANW-7                               7.0-7.5                                  510
                     UVANW-9                               7.0-7.5                                  700
                     UVANW-8                               7.5                                      700
                     UVANW-11                              7.5                                      440
                     UVANW-10                              7.0-7.5                                  435
                     UVANW-3                               7.0-7.5                                  505
                     UVANW-2                               7.0-7.5                                  590
                     UVANW-1                               7.0-7.5                                  310
                     UVANW-4                               7.5-8.0                                  650


                Surface water

                Injection site                                                                      530
                     Station 1                                                                      600
                     Station 2                             7.0-7.5                                  600
                     Station 3                             7.0-7.5                                  510
                     Station 4                             7.0-7.5                                  550
                     Station 5                             7.0-7.5                                  520
                     Station 6                             7.0-7.5                                  520
                     Station 7                             7.0-7.5                                  500
                     Station 8                             7.0-7.5                                  500
                     Station 9                             7.0-7.5                                  490
                     Station 10                            7.0-7.5                                  500

























                                                                        29









                Table 2.3. Storm events during field season.

                                    Julian                           24-hour           Rainfall
                Storm               Date             Date              time            amount
                                                                                        (cm)


                1                   142              05/22               100
                                    142              05/22             1800            2.25
                2                   146              05/26             2030
                                    147              05/27             1430            2.50
                3                   149              05/29               200
                                    149              05/29             2000            2.38
                4                   154              06/03             1900            0.63
                5                   165              06/14               ---a
                                    172              06/21               --- a         1.25
                6                   173              06/22             1600            0.38
                7                   181              06/30             2000            2.25
                8                   192              07/11             1800
                                    193              07/12               600           1.25
                9                   194              07/13             2200            0.75
                10                  195              07/14             1200            0.50
                11                  197              07/16             1800            0.50
                12                  198              07/17             1700            7.25
                13                  202              07/21             1600            2.50
                14                  218              08/06             2000
                                    219              08/07               400           2.75
                15                  221              08/09               400           1.88
                                    221              08/09             1700            1.75
                16                  227              08/15             1800            3.13
                17                  231              08/19             1500            1.75
                18                  236              08/24               200
                                    236              08/24             1300            2.50
                19                  256              09/13               800
                                    256              09/13             1600            2.8


                a =time of storm event unknown





















                                                                       30









              Table 2.4.  Summary of University of Virgina field instrumentation. For locations of instruments,
              refer to Figures 2.2 and 2.3.

              Instrument                     Elevations                                Depth of
                                       Top of          At ground                       screened
                                       casing          surface                         interval
                                                                                  top        base
                                       (m)             (m)                         (cm)          (cm)


              UVAMW-15                 7.46            6.93                      61              107
              UVAMW-14                 8.34            7.85                      61              104
              UVAMW-13                 8.73            8.19                      61              107
              UVAMW-12                 9.24            9.16                      82              143
              UVAMW-11               10.48             10.47                    131              177
              UVAMW-10                 9*95            9*55                      67              113
              UVAMW-9                10.18             9.30                      23              68
              UVAMW-8                  9.77            9.30                      64              107
              UVAMW-7                10.31             9.40                      15              64
              UVAMW-6                  9.89            9.40                      61              105
              UVAMW-5                11.79             10.86                    183              244
              UVAMW-4                  9.67            9.24                      86              124
              UVAMW-3                10.45             10.28                    186              216
              UVAMW-2                  8.78            8.35                      74              104
              UVAMW-1                  9.38            8.33                      18              48
              UVAPZ-4                  7.23            6.71                     193              254
              UVAPZ-3                11.41             10.35                    533              610
              UVAPZ-2                  9.52            8.19                     655              732
              UVAPZ-1                  5.39            4.58                     244              274
              UVALP-1                  4.58            3.85                      91              152
              UVALP-2                  4.50            3.76                      15              76
              UVALP-3                  4.00            3.76                     107              134
              UVALP-4                  4.11            3.7438                    48              84
              UVALP-5                  4.98            3.74                      85              116


              Tensiometers


              T4                       4.68            4.30                                      52
              TIO                      5.00            4.50                                      78
              T12                      4.87            4.13                                      58


              Flumes


              North Branch                             9.13
              Discharge Stream                         0.58










                                                                   31








           Table 2.5. Summary of head differences (in cm.) among nested piezometers in the North
           Branch channel.


           Well nest                 UVAMW-9             UVAMW-7             UVAMW-2
                                     UVAMW-8             UVAMW-6             UVAMW-1



           average
           difference                    2.5                  8.1                  7.5


           standard
           deviation                     2.9                 10.0                 12.2




















































                                                      32








             Table 2.6. Summary of stream lengths and corresponding drainage sub-areas delineated for inflow
             estimates to Hipps Pond. Groundwater contributing areas and storm-flow source areas were
             measured from the site map (Fig. 2.1) and the survey map (Fig. 2.3), respectively.

                                     Site Map                               Survey map

                                                                               Flood          Flood
             Drainage          Length          Area             Length         plain          plain
             area               (m)            (m  2)              (m)        width           area
             ID *                                                               (m)           (m  2)


             NB-TOP              107           49600               122            3           370
             NB-1                 30            8000                30            3             90
             NB-2                 30            6200                34            3           100
             NB-3                 30            5100                30            6           190
             NB-4                 30            4900                30            6           190
             NB-5                 60           16400                60            8           470
             NB-6                 90           16500                60            9           560
             NB-7                160           39500                80          15            1260
             NB-8                130           23000               210          23            4900
             NB-9                 80           18000                76          26            2000


             NBTR-TO                           23400
             NBTR- 1              70            5000
             NBTR-2              100            6000                90            5           420


             Total NB            980           227000              800                       10500


             SB-TOP                            44200
             SB-1                110           21200                80            5           350
             SB-2                 90           10500               110            6           650
             SB-3                 90            7000                80            9           700
             SB-4                110            9500               160          26            4200


             SBTR-TOP                          19300
             SBTR-1               70            5700               100            3           300
             SBTR-2              120            9500               110            1           130


             Total SB            600           120000              600                        6200


             MC-TOP                            26000
             MC_ 1               210           41400               210            3           630


             SL                                43000
             NL                                46000



             TOTALS              1800          503500                                        17200



               for explanation of drainage area IDs, see Table 2.6a.



                                                                 33








                Table 2.6a. Explanation of drainage area IDs referred to in Table 2.6.

                Drainage           Explanation
                area
                ID



                North Branch

                NB-TOP             North Branch above injection point to headwaters
                NB-1               Injection point to station 1A
                NB-2               Stn. 1 to Stn. 2
                NB-3               Stn. 2 to Stn. 3
                NB-4               Stn. 3 to Stn. 4
                NB-5               Stn. 4 to Stn. 5
                NB-6               Stn. 5 to major trib entrance
                NB-7               confluence with major trib (NBTR) to major south bend
                NB-8               major bend to NB/SB confluence
                NB-9               below NB/SB confluence to inflow culverts of Hipps Pond

                NBTR-TOP           headwater area of major tributary of North Branch

                South Branch


                SB-TOP             South Branch headwater area
                SB-4               below trib confluence to confluence with North Branch

                SBTR-TOP           headwater area of major tributary of South Branch

                Marsh Creek


                MC-TOP              marsh creek" headwater area

                Direct drainaze areas into Hi1212s Pond

                SL                 South drainage area of Hipps Pond
                NL                 North drainage area of Hipps Pond

















                                                                       34








               Table 2.7. Summary of stream dilution gaging results. See Table 2.6a for explanation of drainage
               area IDs. See Figure 2.3 for location of sampling stations.

               Drainage        Sampling        Inflow        Length      Drainage          Inflow             Inflow
               Area            station         rate         between         area           per unit           per unit
               ID                                            stations         2)           length             area    2)
                                               (L/s)             (m)       (m              (L/s m)            (L/s m


               NB-1            1
               NB-2            2               0.12              38         6200           3.2E-03            1.9E-05
               NB-3            3               0.11              31.        5200           3.5E-03            2.1E-05
               NB-4            4               0.11              31         5000           3.5E-03            2.2E-05
               NB-5            5               0.32              61         16400          5.2E-03            2.OE-05


















































                                                                    35








              Table 2.8. Inflow rates measured with in-stream seepage meters on the North Branch. For
              locations of stations, refer to Figure 2.3.

              Location                       Sample period                            Flux
                                          start           end                         (m/day)


              Station 1                   07/02           07/09                       5.OE-04
                                          07/09           07/12                       9.5E-04
                                          07/17           07/24                       3.9E-04


              Station 2                   06/06           06/06                       5.5E-03
                                          06/07           06/07                       1.7E-02
                                          06/13           06/13                       1.1E-02


              Midway between stations 3 and 4
                                          07/03           10/18                              0


              Station 4                   06/07           06/13                       5.OE-04
                                          06/13           06/21                       4.5E-04
                                          06/21           06/27                       5.3E-04






























                                                                 36








              Table 2.9. Summary of groundwater gradients. See Figures 2.2 and 2.3 instrument locations.


                                        Transect                                    Date

                                  Upper             Lower                 7/2/90           8/24/90


              HiI212s Pond
              Lateral


                                  UVALP-3           Pond                  0.03             0.005
                                  ESIMW-13          Pond                  0.02             0.022
                                  ESIMW-13          ESIMW-9               0.022            0.027
                                  ESIMW-9           Pond                  0.005            0.004
                                  ESIPZ-2           Pond                  0.034            0.03
                                  UVAPZ-1           Pond                  0.012            0.007
                                  UVAPZ-2           Pond                  0.014            0.011
                                  UVAPZ-3           Pond                  0.013            0.01
                                  UVAPZ-3           UVAPZ-2               0.009            0.007
              Vertical            UVAPZ-2           UVAPZ-1               0.015            0.013

                                  UVALP-1           UVALP-2               0.012            0.32
                                  UVALP-4           UVALP-5               0.22             0.21
                                  UVALP-5           Pond                  0.061            0.041
              South Branch        UVALP-2           Pond                  0.043            0.033
              Lateral
                                  ESIMW-11          ESIMW-12              0.007            0.007
                                  ESIMW-11          creek level           0.01             0.008
                                  ESIMW-10          creek level           0.013            0.011
                                  ESIMW-12          creek level           0.012            0.01
                                  ESIMW-7           creek level           0.032            0.025
                                  ESIMW-4           creek level           0.043            0.039
                                  ESIMW-3           creek level           0.047            0.049
                                  ESIMW-2           creek level           0.051            0.043
                                  UVANW-14          creek level           0.051            0.048
                                  UVANW-4           creek level           0.06             0.07
                                  UVANW-5           creek level           0.042            0.036
                                  UVANW-10          creek level           0.055            0.087
                                  UVANW-11          creek level           0.042            0.050
                                  UVANW-11          UVANW-10              0.033            0.026
              Vertical


                                  UVANW-1           UVANW-2               0.21
                                  UVANW-6           UVANW-7               0.125
                                  UVANW-8           UVANW-9               0.045








                                                                   37








               Table 2.10. Comparison of estimated groundwater inflows to the North Branch. For locations of
               piezometer nests, refer to Figure 2.3.
                                      TOTAL             LATERA@                VERTICALC        VERTICALd
                                      INFLOW            INFLOW

               location               measured          calculated             measured         calculated
                                      (M3 /day m)       (M3 /day m)            (m 3/day m)      (M3 /day m)
               UVANW-1/NW-2           2.7E-01           3.6E-0 1 e             2.5E-04  )h      9.1E-02'
                                                        3.6E-02'               (1.8E-05         9.1E-039
               UVANW-6/NW-7           2.7E-01           3.6E-0 1 e             5.7E-03  )h      5.4E-02'
                                                        3.6E-02'               (2.4E-03         5AE-03 9
               NW-8/NW-9              2.7E-01           3.6E-Ole               3.1E-04  )h      1.9E-02'
                                                        3.6E-02'               (1.2E-04         1.9E-039


               Method:

               ' = in-stream dilution experiment
               b = Darcy's law with observed water levels
               ' = in-stream seepage meters
               d = Darcy's law with observed heads

               Estimated hydraulic conductivites:

               e = K    1E-02 cm/s
               f = K    1E-03 cm/s
               9 = K    1E-04 cm/s
               hNumbers in parentheses represent 1 standard deviation from the mean.
















                                                                 38









              Table 2. 11. Monthly water budget on Hipps Pond.

                                             INPUTS                       OUTPUTS


                                    Surface
                                Base     Storm            Ground Outfall               Dam
              Month             Flow     Flow      Rain    Water Discharge      PET    Seepage     STORAGE RESIDUAL



              July            10000      2500      3200     48       12000      8000    58        -1200            -3700

              August            8100     2000      3500     46        8600      5200    56          800            -1000

              September         5100      900       700     48        3800      3400    58        -1200              600



              ï¿½ negative value for storage change indicates a net loss of water in the pond.

              A positive value for storage change indicates a net gain of water in the pond.

              ï¿½ negative residual indicates that the sum of outputs and storage exceeds the total input. A
                       negative residual results if total inputs exceed the sum of outputs and storage.




























                                                                    39








               Table 2.12. Contributions of water budget components of Hipps Pond for selected base flow
               intervals. All components expressed as fluxes over Hipps Pond area.

                      Date
               start        end             Total          Pond          Outfall             PET           Residualb
                                            input'         stage         discharge
                                                           drop
                                            (cm/d)         (cm/d)        (cm/d)              (cm/d)        (cm/d)


               07/02        07/09           1.12           0.47          1.02                1.10          -1.47
               07/09        07/11           0.78           0.22          0.62                1.26          -1.33
               07/27        07/31           2.27           0.42          0.78                0.88          0.20
               07/31        08/03           2.01           0.36          0.45                0.83          0.36
               08/03        08/06           1.78           0.12          0.28                0.83          0.55
               08/25        09/04           0.89           0.60          1.23                0.69          -1.63
               09/04        09/13           0.67           0.08          0.39                0.55          -0.35


               aTotal input = direct groundwater and surface water into Hipps Pond.
               bA negative residual indicates that the sum of outputs and storage exceeds the total input. A
               negative residual results if total inputs exceed the sum of outputs and storage.





























                                                                         40








               Table 2.13. Fluxes of major components into Hipps Pond during selected storm intervals. Each
               value represents the flux over the pond area.


               Date              Rain          Total               Lake             Total                Residualc
                                               surface             level            output
                                               runoffa             rise
                                 (cm)          (cm                 (cm)             (cm)                 (cm)


               06/30             2.25          2.3                 3.5              1.1                  -0.2
               07/11             1.25          0.8                 1.4              1.5                  -0.8
               07/17             7.25          5.1                 8.7              3.4                    0.2
               07/21             2.5           3.0                 5.0              1.3                  -0.8
               08/06             2.75          0.8                 4.5              1.4                  -2.4
               08/19             1.75          1.2                 2.5              1.7                  -1.2


               aTotal surface runoff       storm flow from all creeks.

               bTotal output = total storm minus related discharge through the outfall stream.

               'A negative residual indicates that the sum of outputs and storage exceeds the total input. A
                        negative residual results if total inputs exceed the sum of outputs and storage.





























                                                                         41








             Table 2.14. Estimated uncertainties in monthly water budget components of Hipps Pond. Adapted
             in part from Winter (1981).

                Component                                    Percent Error


             PRECIPITATION
                Gauge                                              3
                Placement                                          5
                Areal Averaging                                    5
                Gauge Density                                      10
                    Total Error                                    23



             POND EVAPORATION
                Energy Budget                                      25
                Pond Area                                          10
                    Total Error                                    35


             STREAM FLOW IN
             Base flow
                Stage-Discharge Relationship                       5
                Channel Bias                                       5
                Areal Groundwater Inflow Rel.                    100
                    Total Error                                  110


             Storm Flow
                Stage-Volume Relationship                          45
                Area-Yield Relationship                          130
                    Total Error                                  175


             STREAM FLOW OUT
                Stage-Discharge Relationship                       5
                Channel Bias                                       2
                    Total Error                                    7


             LAKESTORAGE
                Lake Area                                          10
                Stage-Water Level Record Rel.                      5
                    Total Error                                    15


             DIRECT GROUNDWATER INFLOW
                Gradient                                           15
                Flux Area                                          20
                Hydraulic Conductivity                           200
                    Total Error                                  235


             DAM SEEPAGE
                Gradient                                           15
                Flux Area                                          20
                Hydraulic Conductivity                           200
                    Total Error                                  235


                    Overall Error                                777%




                                                            42






            Figure 2.1
                                                     CHEATHAM ANNEX
                                                                 SITE MAP



                                                                                                                                       LEGEND
                                                                                                                              El          MAP INSET
                                                                 0
                                                    63                  67



                                                    MORIN











                                                                              SWIM


                                                                                                                 POND
                                                                                                                               Ak%-

                                                                                                            So. w
                                                                                                             N.


                                                                                             54     44


                                                                                51










                                                                           Q*.-A












                                                                                                                     04
                                                                                                                     CRAX,
                           0           600
                     SCALE -              FEET






                                                                                                             CHEATHAM ANNEX PROJECT
                                                                                                  Department of Environmental Sciences
                          (Taken from: ESI, 1989)                                                                University of Virginia
                                                                                                                    December 1, 1990



                                                                                        43







       Figure 2.2
                                        MW5                     HIPPS POND
                                                       INSTRUMENT LOCATIONS



                                                                   LEGEND


                                                                   ESI WELL

                                                               0   PIEZOMETER

                                                               CO  PIEZOMETER NEST

                                                                   FLUME

                                                                   TENSIOMETER NEST


                e






                        P 3

                                           LP3



                           MW13
                                            LP4/5


                   Mw













                       MW6
                                                            L?
                                                   PZ1    R@


                                   PZ3      PZ2
                                   0        0








               SCALE
                                                              CHEATHAM ANNEX PROJECT
                                                        Department of Enyironmental Science
                             M    GENERAL CONTOUR 44             Uniyersity of Virginia
         30       0       30     INTERYALIN METERS                 December 1, 1990






             Figure 2.3                 NORTH BRANCH
             INSTRUMENT LOCATION AND SAMPLING STATIONS



                     LEGEND                                                   NW 14
                                                                         MW7

                     ESI WELL
                                                                                   NWIS
                 o PIEZOMETER
                                                                   Sin a
                co PIEZOMETER       NEST
                                                       MW2
                     FLUME                              Q5   Stn 7
              Stn I SAMPLING STATION                 Stn 6


                                      NW5    MW4
                                       0      e              I

                                              ,Stn 5
                                           NW4          NW 13
                                   NW 1/2          Stn 4  %lb

                                   Stn 3
                                                     'NW 3
                           FLUME SO 2         NW12f

                         NW6/7
                                                     NW10
                                            N        NWI I
                      NW8/9


        injection Point
                       el'oez"@o Stn I                 SCALE                                                   CHEAT
                                                                   M                                    Department
                                                                          CONTOUR INTERVAL                        Uni
                                                   30     0     30
                                                                               I METER                              D



               L

         Figure 2.4  NORTH BRANCH
              FLOODPLAIN DELINEA FION





                   LEGEND


                    FLOODPLAIN








       0)













                                         SCALE                                       CHEAT
                                                   M                            Department
                                      30    0   30                                     Univ
                                                                                         D








        Figure 2.5




                BATHYMETRY OF HIPPS POND













                                     2

                                                                     2.5






                   CONTOUR INTERVAL                                 CHEATHAM ANNEX P
                      0.5 METERS
                                                               Department of Environme
                    SCALE 1:38                                        University of Vir
                                                                        December 1, 1 S









             Figure 2.6. Pond response to a storm event. In nearly all pond storm hydrographs, stage
             increased rapidly and stabilized to a near-constant height.



                  71 Pond level stage (cm)                                        Rainfall (cm)

                  70-                                                                       2.25


                  69




                  68




                  67 -

                  66 1L

                  65
                    179    180     181     182     183    184     185     186     187    188     189
                                            Julian day (179       28 June)










                           AM 111"IN N E X P ROJ ECT

             DePc.-:.men', of Environmental Sciences

                       .1
                       Jniversity of Virginia

                        _._.@emter 1, 1990






                                                          48





                Figure 2.7. Comparison of response traces duringand following a storm event. The wide
                variability of the tensiometer recordagainst the "actual" lake response is evident.


                 P8


                 8
                                                     Lake tensiorneter response
                 84


                 82


                 80


                 78

         E       76
         0
                 74
         a)      72
         >


                 70

         0)
                 68
                                                     Lake level recorder response
         U)      66 -

                 64 -


                 62 -


                 60 -


                 58 -                                                            --T

                   202.4         202.8         203.2        2 0,-') - G    204          204.4
       CHEATHAM AFINEX PROJECT              Julian day (202          21 July)
  Dr--porlinpFif of Environmenini Sclences

          Univ(.-i'sily of Virolnio

           December 1, 1990





                        Figure 2.8. Daily temperature cycles over a three-day period. This record extends over the same
                        period as in Figure 2.7.


                   40

                   39  -

                   38  -

                   37  -

                   36  -

                   35  -

                   34  -

                   33  -

                   32  -

          ca       31  -
          L_
       Ln (D       30  -
       0  OL
          E        29  -
          (D
                   28

                   27  -

                   26  -

                   25  -

                   24  -

                   23  -

                   22

                     202.4          202.8           203.2          203.6           204           204.4
        CHEATHAM ANNE    'X PROJECT                Julian day (202             21 July)
   Departmeni of Environmental Sciences
            University of Virginia
             December 1, 1990










            Figure 2.9. North Branch responses to three storm events.




                0.7 Discharge (1/s)                                             rainfall (cm)


                0.6 -




                0.5 -




                0.4




                0.3




                0.2




                0.1
                   193           194            195           196            197            198
                                          Julian day (193      12 July)










                             ANNEX PROJECT

                   iment of  L"nvironmental Sciences

                     Un.,,versity of Virginia

                      December 1, 19QO





                                                       51









            Figure 2.10. Subsurface responses near the North Branch to three storm events. The highest
            responses generally cluster in floodplain and riparian areas of the creek.



                 50 Water level rise (cm)


                                                                           Rainfall (cm)
                 40-
                                                                                 2.8


                                                                                 2.5

                 30                                                   0          7.2




                 20'




                 10,-



                                             +
                  0              1            1
                    0           2            4            6           8            10          12
                                         Distance -from creek (meters)











                 '-L-;E-!-_HAM ANNEX PROJECT
                   .1 -1.1


                  r: 7n  t
                           cf -rivironmental Sciences

                      University of Virginia

                       Der-cern!Der 1, 191;0





                                                        52









            Figure 2.11. Runoff yields from the North Branch floodplain above the flume for a series of
             storms.




                  10 Storm water flux (cm)


                   8 -





                   6



                                                                        100 % yield line
                   4





                   2





                   0
                    0                    2                    4                    6                    8
                                                       Rainfall (cm)











                                ANNEX PROJECT


                            of Environmental Sciences

                      University of Virginia

                        Decemlzer 1, lQQ0





                                                               53








          Figure 2.12. Water levels records from well UVAPZ-1 during a series of storms. Even during the
          largest storm, the water level rise is relatively minimal compared to weekly drawdowns.


              44  Relative water level (cm)                               Rainfall (cm)

              43




              42
                                                                                     10



              41




              40




              39




              38
                 178 180 182 184 186 188 190 192 194 196 198                           200
                                            Julian day










                 Li E @4 1
                         M AIINZX PROJECT

                   en Iof Environmental Sciences

                   I.-versity of Virginia

                    December 1, 1990





                                                    54









                                                    111. ORGANICS


                                                     IIIA. Introduction


                     During its period of operation the Cheatham Annex site was used as a repository for a

              variety of petroleum products. Several spills and leaks on site have been documented, and

              interviews with former employees revealed the presence of several waste disposal pits which

              contained mixed sludges of unknown composition. Initial investigations by Engineering-Science,

              Inc. (ESI) under contract to the Virginia Deparment of Waste Management (VDWM) also

              indicated that a cosmoline dump existed in the southern portion of the site.

                     Given the nature of the materials stored on site and the operational history of the

              Cheatham Annex site the potential existed for contamination of environmental media by

              petroleum products. It was also recognized that incidental spills in the vicinity of

              loading/unloading valve boxes and oil/water separators would be expected and not uncommon.

              The prospect of leaking storage tanks poses a greater threat to the site as a whole, relative to the

              more confined regions, but definitive evidence of such an occurrence is possible only by adopting

              an aggressive excavation program. Such an approach is currently undesirable. It was decided,

              therefore, that the extent of potential contamination would be assessed through the collection and

              analysis of sediment, surface water, and well water samples. These samples were collected under

              the assumption that the Hipps Creek - Hipps Pond system is currently the dominant hydrologic

              force in the system and the primary route through which material from the subsurface is exported

              from the site.



                                                        11111. Methods


                                        Collection of Samples for Organic Analysis


                     The location and nature of all samples collected for organics analyses are summarized in

              Table 3.1. All samples are described in Appendix L



                                                                55









              Water Samples


                     The water samples were collected by submerging the sampling jars 1-5 cm below the

              surface. The jars were filled completely and no air was allowed to remain in the jars as they were

              sealed. The samples were collected and stored in either 0.5-L amber or 1-L red Teflon-coated

              glass jars with screw lids. The samples were placed in an ice-filled cooler and later stored under

              refrigeration prior to analysis. During the collecteion procedure rubber gloves were worn at all

              times.

                     The pond water samples were collected before the sediment samples in each location.

              This prevented contamination of the water sample by agitated bottom sediments.

                     Groundwater samples were collected from wells installed at least three weeks previous to

              the collection date (see section IIC of this report for well construction details). A minimum of

              three well volumes of water were evacuated from each well prior to sampling. Most samples were

              collected using a stainless steel WILCO sampler which was rinsed with deionized water before

              each sample was collected. Sample LP-3 was collected from a one-inch-diameter piezometer

              which was too small for the Wilco sampling device; this sample was collected using a Nalgene

              hand pump fitted with Tygon tubing.


              Sediment Samples


                     The two mid-pond sediment samples (S-4, S-5) were collected using a steel Wilco

              sediment bucket sampler. Samples were collected to a depth of 10 cm below the sediment-water

              interface. During sampling rubber gloves were used at all times. The bucket was rinsed after

              each sample was collected.

                     The pond-side sediment sample (S-6) was collected using a hand auger which collected to

              a depth of 15 cm. The North Branch floodplain sediment sample (S-7) was collected using a

              shovel to a depth of 5 cm.

                     No further effort was made to separate distinct layers of sediment; thus, all samples
              analyzed were of integrated sediment. All sediment samples were placed in sealable plastic bags

                                                               56









                from which as much air as possible was removed. The samples were placed in a cooler filled with

                ice and frozen immediately upon return to the lab.


                                                         Laboratory Methods


                       Prior to use, all glassware was rinsed with fresh solvent (methylene chloride; CH        2Cl@), acid
                washed in a solution of Nochromix (Godax Laboratories, New York) and sulfuric acid (H                2SO4)1

                triple rinsed with deionized water and oven dried. The methylene chloride used was Burdick and

                Jackson Chrompure HPLC solvent (catalogue no. CP80175-4; Baxter, Burdick and Jackson

                Division, Muskegon, MI).
                        Sediment samples were extracted in a Soxhlet apparatus using 250 mL of CH              2Cl 2 as the
                extraction solvent. At the time of analysis, samples were thawed and homogenized, five replicate

                cores (approximately 3 g each) were collected and placed in tared, single-thickness cellulose

                extraction thimbles (Whatman, catalogue no. 2800-258). The total mass of the sediment plus

                thimble was recorded and the mass of sediment collected for extraction was determined. The

                composite sample was mixed with an equal mass of anhydrous sodium sulfate (Na                 2so 4) in the
                extraction thimble, and the thimble was then placed in the Soxhlet apparatus. Sediment samples

                were extracted for 16 hours. The heat source was adjusted such that the samples were extracted at

                the rate of approximately 20 minutes per cycle.

                        Upon completion of the extraction procedure, The extract was dried over anhydrous

                Na 2so 4 and transferred to a Kuderna-Danish (K-D) concentration apparatus equipped with a

                three-ball macro Snyder column. The K-D apparatus was immersed in a hot water bath, and the

                extract was concentrated to an apparent volume of -4 mL. The concentrated extract was allowed

                to cool, and the final volume of extract was recorded. A subsample of the concentrated extract

                was transferred to a 2-mL glass serum vial which was subsequently sealed with a crimp seal with a

                Teflon-lined rubber septum. The vial was filled and sealed to allow for minimal headspace. These
                sealed samples were stored at 4' C until analysis by gas chromatography could be performed. A 1-
                mL subsample of the concentrated extract was transferred to a tared 2-mL glass serum vial. The

                                                                      57









              vial was not sealed and the solvent was allowed to volatilize off after which the vial was reweighed.

              The difference in weight was recorded and used in the calculation of total extractable

              hydrocarbons.

                      Water samples were filtered through Whatman number 4 qualitative filters, and a
              measured volume of the filtered sample was extracted with 200 mL CH       2Cl@ in a continuous liquid-
              liquid extraction apparatus (catalogue no. 584210-0000; Kontes, Vineland, NJ). Samples were
              extracted for 48 hours. Upon completion of the extraction procedure, the CH         2Cl2 fraction was
              collected, dried over anhydrous Na  2so 4 and concentrated as detailed above.

                      Water samples WW-14 and WW-15 were filtered through tared Whatman number 1

              qualitative filters. The aqueous filtrate was then extracted as detailed above for water samples.

              Ile filters were reweighed, and the filter and retained solids were extracted by Soxhlet extraction

              as detailed above.

                      Gas chromatography was performed on a Varian model 3300 gas chromatograph (Varian

              Associates, Sunnyvale, CA) equipped with a DB-5 fused silica capillary column (30 m x 0.32 mm

              i.d.; film thickness 0.25 tim; J&W Scientific, Folsom, CA) and flame ionization detector. Nitrogen

              was used as the carrier gas and the influent line was equipped with a moisture trap (gas filter

              model DGF-125; LabClear, Oakland, CA) and a hydrocarbon trap (Supelco rechargable

              hydrocarbon trap; Supelco, Inc., Bellefonte, PA). A splitless injection of 1.0 AL was made and the

              column oven temperature was programmed as follows: 85' C for 4 minutes, ramp to 270' C at 101

              C per minute, hold at 270' C for 58 minutes. Injector and detector temperatures were maintained

              at 270' C. Chromatograms were recorded and the area under each peak was determined using a

              Varian model 4290 integrator.

                      Qualitative and quantitative analysis of sample chromatograms was achieved by

              comparison to standard chromatograms which were generated by analyzing a set of standard

              solutions of polynuclear aromatic hydrocarbons (PNA's)(PAH kit 610-S, catalogue no. 4-8755M;

              Supelco, Inc., Bellefonte, PA) under the chromatographic conditions set forth above.



                                                                 58









                                                      111C. Results


                    All samples were analyzed for the presence of the sixteen PNA's listed in Table 3.2. For

              sediment samples, the concentrations of six of these compounds is listed. The remaining ten

              PNA's were not detected in any sediment sample analyzed. For water samples the concentration

              of fourteen PNA's is reported. The remaining two PNA's were not detected in any of the water

              samples analysed.

                     Tables 3.3 through 3.9 indicate the concentration of PNA's in sediment and water samples.

              Concentrations are reported in parts per million (ppm; micrograms per gram dry weight for

              sediment samples; micrograms per milliliter for water samples). Values in Tables 3.3 through 3.9

              represent the mean (standard deviation) of three replicate injections per sample, except where

              indicated otherwise. Sampling locations are indicated on Figure 3.1.

                     All three sediment samples collected from Hipps Pond were found to contain PNA's

              (Table 3.3). Sample S-4 was collected from the northwest end of Hipps Pond near the surface

              water inflow. The analyses indicated that these sediments were dominated by acenaphthylene

              (78.22 ppm) and acenaphthene (40.93 ppm) with a total concentration of about 150 ppm PNA's.

              Sample S-6 was collected approximately one foot from the southern shore of Hipps Pond about

              midway along the length of the pond. Although this sample cotained a smaller overall mass of

              PNA's (99.40 ppm) it had a substantially higher mass of total extractable hydrocarbons (TEH).

              Sample S-5 was collected from the southeast end of Hipps Pond and also indicated elevated levels

              of acenaphthylene (86.11 ppm) and acenaphthene (45.19 ppm) with a total PNA value of

              approximately 10,000 ppm.

                     Sample S-7 was (Table 3.3) collected from the flood plain of the North Branch of Hipps

              Creek downstream from the sludge pit. Because acenaphthylene was detected in only one of three

              replicate chromatograms a reliable statement about the presence of this compound cannot be

              made. Sample S-7r (Table 3.4) was a replicate sample gathered from the flood plain of the North

              Branch. If present, the PNA's for which analyses were conducted were at levels below the limit of
              detection.                                      59









                      Sediment samples S-1, S-2, and S-3 were collected from seepage faces along Perimeter

              Road in the southeast quadrant of the site (Figure 3.1). Any PNA's present were below the limits

              of detection.

                      UVAPZ-4s and UVALP-3s (Table 3.5) represent the solid fraction which was filtered

              from water samples collected from UVAPZ-4 and UVALP-3 (see section IIC of this report for

              well construction details). UVAPZ-4 was located south of Hipps Pond upgradient of the marshy

              inflow to the pond. Analyses indicated that all compounds if present were below the limits of

              detection for sample UVA-PZ-4s. Well UVALP-3 was installed approximately one foot from the

              edge of Hipps Pond about midway along the length of the southern edge of the pond. As indicated

              in the notes accompanying Table 3.5, the water sample collected from this well contained a much

              larger mass of suspended solids. Acenaphthylene, acenaphthene, and fluorene were detected in

              sample UVALP-3s. In terms of the results of the PNA anlysis UVAPZ-4s and UVALP-3s are

              very different, but these two samples appear to be similar in terms of TEH. It is important to note

              that the low mass of suspended solids in the water sample collected from UVAPZ-4 (1.56 g)

              resulted in substantially higher limits of detection for sample UVAPZ-4s relative to sample

              UVALP-3s.

                      Water samples SW-5(8/2) and SW-6(8/2) were collected in early August 1990 from the

              North Branch of Hipps Creek and South Branch of Hipps Creek, respectively (Table 3.6). samples

              A second round of samples were collected in early September 1990 [SW-5(9/3), North Branch;

              SW-6(9/3), South Branch; Table 3.7]. PNA's were not present above detection limits in any of

              these four samples.

                      Water sample SW-12 was collected from the swampy inflow area to the south of Hipps

              Pond (Figure 3.1). PNA's were not present above detection limits in this sample (Table 3.6).

              Sample SW-8(8/2) was collected from the outflow of Hipps Pond in early August 1990 (Table 3.6)

              and a second sample [SW-8(9/3), Table 3.7] was collected in early September. Neither sample

              contained PNA's at levels above the detection limit.

                      Water samples from the middle of Hipps Pond were gathered in early August 1990 from

                                                                60









              the northwest (LW- 1 + LW- 1r) and southeast (LW-2 + LW-2r) portions of the pond (Table 3.8,

              Figure 3.1). Several compounds were detected in sample LW-1+LW-lr but these compounds

              were detected in the same single chromatograrn and were not detected in either of the other two

              replicate chromatograms. Analysis of sample LW-2+LW-2r indicated the presence of small

              amounts (0.16 ppm) of naphthalene.

                     Water samples SW-9, SW-10, and SW-11 were collected from seepage faces from the

              southeast quadrant of the Cheatham Annex site along Perimeter Road (Figure 3.1). Analyses

              indicate that PNA's are not present in samples SW-9 and SW- 11 (Table 3.7 and 3.8, respectively).

              However, detectable amounts of acenaphthylene, phenanthrene, benzo(a)anthracene,

              indeno(1,2,3-c,d)pyrene, and dibenzo(a,h)anthracene were found in sample SW-10 (Table 3.8)

                     Water samples were collected from wells UVAPZ-4 and UVALP-3 and given the same ID

              number (Figure 3.1). All PNAs were below limits of detection for sample UVA-PZ-4 (Figure 3.9)

              but small amounts of naphthalene (0.37 ppm) and acenaphthylene (0.52 ppm) were found in

              UVALP-3.



                                                      IIID. Discussion


                     Previous sampling schemes at     the Cheatham Annex site were designed to locate and

              identify those areas within the site which are contaminated with petroleum products. In contrast,

              the sampling scheme used in the current investigation was designed to identify the extent of

              potential contamination within the site. Within this framework, it is recognized that smaller scale

              regions of high contaminant concentration may exist within a much larger region of relatively low

              or no contaminant concentration. Due to the differences in sampling philosophy, therefore, the

              results reported herein may not be directly comparable to previously reported results. It does

              remain possible to compare samples gathered from sites in close proximity to one another and

              these comparisons are made where relevant. However, one may generate diametrically opposite

              conclusions about the site as a whole due to the differences in sampling scheme previosly

              described.


                                                               61









                      Surface water samples which were gathered in August and September 1990 were generally

              free of contamination by PNA's. Surface water sample replicates SW-6(8/2) (Table 3.6) and SW-

              6(9/3) (Table 3.7), which were collected from the South Branch of Hipps Creek contained no

              detectable levels of PNA's and had very low quantities (<3 ppm) of total extractable

              hydrocarbons JEH). These results are in agreement with those reported by ESI. PNA's and TEH

              in replicate water samples collected from the North Branch of Hipps Creek [SW-5(8/2), Table

              3.6; SW-5(9/3), Table 3.7] were similarly absent and in low concentration, respectively.

                      Water samples from the second round of sampling collected from the discharge stream of

              Hipps Pond [SW-8(8/2), Table 3.6; SW-8(9/3), Table 3.7] contained no PNA's and also had low

              levels of TER These results also agree with those reported previously by ESI.

                      Several PNA's were detected in pond water sample LW- 1 + LW- 1r (Table 3.8) but the

              presence of these compounds could not be reliably detected in replicate chromatograms. It is

              therefore doubtful that the compounds indicated in Table 3.8 are present at levels above detection

              limits. Pond water sample LW-2+LW-2r was also found to be free of high concentrations of

              PNA's. These results are also in agreement with those reported by ESI.

                      Well water sample UVAPZ-4 (Table 3.9) was collected near the swampy area to the south

              of Hipps Pond and downgradient of an oil/water separator. This sample was free of PNA's.

              However, sample UVALP-3 was contaminated with low concentrations of naphthalene and

              acenaphthylene. Naphthalene and acenaphthylene are both considered to be insoluble in water

              (CRC Handbook of Chemistry and Physics) and are more likely to be associated with the solid

              fraction of the sample. UVALP-3 had a large suspended solid load (footnote, Table 3.5) and

              although the sample was filtered prior to extraction, it is likely that some of these solids passed
              the Whatman *1 qualitative filter. At the end of the extraction process, a noticeable film of
              sediment had settled out on the CH      2Cl 2-water interface. The PNA's detected are therefore
              thought to have been associated with the solid fraction of the aqueous sample and not dissolved in

              the water itself. UVALP-3s (Table 3.5), the solid fraction from UVALP-3, was contaminated with

              acenaphthylene, acenaphthene, and fluorene whereas UVAPZ-4 was not contaminated with

                                                                62











              PNA's.

                      All sediment samples gathered from the southeast quadrant of the site (S-1, S-2, S-3;

              Table 3.4) and those collected from the flood plain of the North Branch of Hipps Creek were free

              of contamination by PNA's.

                      Lake sediment samples, however, contained elevated levels of both PNA's and TEH. In

              the preliminary draft, ESI documented two major oil spills into Hipps Pond. The first occurred in

              April 1977 when 240,000 gallons of number one fuel oil (home heating oil) were spilled. Oil

              recovery operations were immediately implemented and approximately 200,000 gallons were

              eventually recovered. In April 1978 an unknown volume of Number 6 (heavy black) fuel oil was

              spilled into Hipps Pond and allowed to remain in the pond for up to five months. Although oil

              recovery was hampered by leaves and other debris, approximately 44,000 gallons were eventually

              recovered from the pond. Given this history of the pond, the analytical results of the pond

              sediments are not surprising.

                      In summary, the waters of the North and South Branches of Hipps Creek, Hipps Pond,

              and the outflow stream from Hipps Pond are not found to be contaminated with PNA'S. The only

              sediments which were found to be contaminated with PNA's were those collected from Hipps

              Pond. It is believed that this contamination is the result of the documented oil spills and not the

              result of import from Hipps Creek.


                                                       IIIE. Summary


                      The major points for summary from our study of the organic contamination at the

              Cheatham Annex site follow.

                  1) There is not much organic contamination present at Cheatham Annex except in the

                      sediments of Hipps Pond. This contamination may be due to oil spills in 1977 and 1978. It

                      is possible that additional contamination may be trapped by the sediments following high

                      discharge events into the Pond.



                                                               63








              Table 3.1. Information on the nature of the samples collected for organic analysis. Sampling
              locations are indicated on Figure 3.1.

              ID           Date       Location



              Hipps Pond Surface Water
              LW_1         8/2        Hipps Pond, 7 m from inflow
              LW-lr        8/2
              LW-2         8/2        Hipps Pond, mid-pond (Trans 18)
              LW-2r        8/2

              Sediments
              S-1          9/3        perimeter north of Diesel Dr.
              S-2          9/3        perimeter south of Diesel Dr.
              S-3          9/3        perimeter downgradient of cosmoline dump
              S-4          8/2        Hipps Pond, 7 m from inflow
              S-5          8/2        Hipps Pond, mid-pond
              S-6          8/2        Hipps Pond, pond margin
              S-7          8/2        North Branch floodplain, at NW-14
              S-7r         8/2

              Surface Water
              SW-5         8/2        North Branch, before confluence with South Branch
              SW-5         9/3
              SW-6         8/2        South Branch, before confluence with North Branch
              SW-6         9/3
              SW-8         8/2
              SW-8         9/3
              SW_9         9/3        perimeter north of Diesel Dr.
              SW-10        9/3        perimeter south of Diesel Dr.
              SW-11        9/3        perimeter downgradient of cosmoline dump
              SW-12        8/2        swampy inflow to Hipps Pond

              Groundwater
              UVALP-3 10/9            pondside, downgradient of oil/water separator #2
              UVAPZ-4 10/9            upgradient of swampy inflow to Hipps Pond

              Suspended Solids
              UVALP-3s 10/9           pondside, downgradient of oil/water separator #2
              UVAPZ-4s 10/9           upgradient of swampy inflow to Hipps Pond


              Key to meaning of sample names:

              "S" = sediment/soil sample
              "LW" = pond water sample
               SW" = surface water sample
              "LP" = groundwater sample from lake piezometer
              "PZ" = groundwater sample from piezometer
              "r" = replicate
              11s" = solids which were filtered from the water sample



                                                               64







            Table 3.2. Polynuclear aromatic hydrocarbons for which analyses were conducted for water and
            sediment samples from Cheatham Annex.


                   Acenaphthene
                   Acenaphthylene
                   Anthracene
                   Benzo(a)anthracene
                   Benzo(a)pyrene
                   Benzo(b)fluoranthene
                   Benzo(g,h,i)perylene
                   Benzo(k)fluoranthene
                   Chrysene
                   Dibenzo(a,h)anthracene
                   Fluoranthene
                   Fluorene
                   Indeno(1,2,3-c,d)pyrene
                   Naphthalene
                   Phenanthrene
                   Pyrene



































                                                          65








               Table 3.3. Results for organic analyses of Cheatham Annex sediment samples.


                                                 S-4             S-5             S-6              S-7


               Naphthalene                       < 34.48         < 44.16         21.03            < 14.46
                                                                                 (1.02)
               Acenaphthylene                    78.22           86.11           48.01            < 26.19
                                                 (4.29)          (0.44)          (4.93)
               Acenaphthene                      40.93           45.19           27.56            13.44a
                                                 (0.62)          (0.25)          (5.40)
               Fluorene                          16.56           16.54a          < 3.54           < 3.06
                                                 (5.08)
               Phenanthrene                      5.56            6.99            2.80             < 1.64
                                                 (1.73)          (1.57)          (0.01)
               Anthracene                        10.08           12.2 a          < 2.25           < 1.80
                                                 (0.93)
               I PNA's                           151.53          167.04          99.4             13.44

               TEH                               4,094           9,914           10,317           ***b


               Concentrations of polynuclear aromatic hydrocarbons (PNA's) reported as Ag1g dry weight of
                       sediment extracted, Numbers reported represent the mean (standard deviation) of three
                       replicate injections, except where noted.

               TEH = total extractable hydrocarbons; determined gavimetrically and reported asug/gdw
                       sediment.

               a = compound detected in one chromatogram.
               b = final weight less than initial weight.

               < = indicates the compound was not detected at the given minimum detection quantity.


















                                                                     66









                 Table 3.4. Results of organic analyses of Cheatham Annex sediment samples.


                                                      S-1               S-2               S-3                S-7r


                 Naphthalene                          < 12.75           < 4.94            < 4.90             < 6.42

                 Acenaphthylene                       < 23. 10          < 8.96            < 8.88             < 11.62

                 Acenaphthene                         < 11.83           < 4.59            < 4.59             < 5.95

                 Fluorene                             < 2.70            < 1.05            < 1.04             < 1.36


                 Phenanthrene                         < 1.44            < 0.56            < 0.55             < 0.73


                 Anthracene                           < 1.58            < 0.61            < 0.61             < 0.80


                 I PNA's                              ---               ---               ---                ---


                 TEH                                  617               515               313                474


                 Concentrations of Polynuclear Aromatic Hydrocarbons (PNA's) reported as jig/g dry weight of
                          sediment extracted. Numbers reported represent the mean (standard deviatio.n) of three
                          replicate injections, except where noted.

                 T`EH = total extractable hydrocarbons; determined gravimetrically and reported as /Lg/gdw
                          sediment.

                 < = indicates the compound was not detected at the given minimum detection quantity.






















                                                                            67









                Table 3.5. Results of organic analyses of Cheatham Annex solid fraction filtered from water
                samples.


                                                          UVAPZ-4s        UVALP-3s



                Naphthalene                               < 74.22         < 10.44

                Acenaphthylene                            < 134.47        23.16
                                                                          (6.23)
                Acenaphthene                              < 68.86         14.49
                                                                          (6.90)
                Fluorene                                  < 15.73         6.96
                                                                          (7.06)
                Phenanthrene                              < 8.40          1.58a


                Anthracene                                < 9.22          < 1.30


                I PNA's                                   ---             46.19

                TEH                                       2,186           2,837


                Concentrations of Polynuclear Aromatic Hydrocarbons (PNA's) reported as jug/g dry weight of
                         sediment extracted. Numbers reported represent the mean (standard deviation) of three
                         replicate injections, except where noted.

                TEH = total extractable hydrocarbons; determined gravimetrically and reported as gg/gdw
                         sediment.

                a = compound detected in one chromatogram.

                UVAPZ-4s and UVALP-3s represent the solid fractions of water samples UVAPZ-4 and
                         UVALP-3, respectively, which were retained on Whatman *1 qualitative filters.

                         Sample                      Volume filtered (mL)                  Mass retained on filter (g)
                         UVAPZ-4                      1150                                 1.56
                         UVALP-3                      410                                  13.30

                <    indicates the compound was not detected at the given minimum detection quantity.












                                                                      68









                  Table 3.6. Results of organic analyses of Cheatham Annex water samples.


                                                                    SW-8(8/2)          SW-12               SW-6(8/2)           SW-5(8/2)


                  Naphthalene                                       < 0.24             < 0.33              < 0.26              < 0.26

                  Acenaphthylene                                    < 0.43             < 0.59              < 0.47              < 0.48

                  Fluorene                                          < 0.05             < 0.07              < 0.06              < 0.06


                  Phenanthrene                                      < 0.03             < 0.04              < 0.03              < 0.03


                  Anthracene                                        < 0.03             < 0.04              < 0.03              < 0.03


                  Fluoranthene                                      < 0.03             < 0.04              < 0.03              < 0.03

                  Pyrene                                            < 0.02             < 0.02              < 0.02              < 0.02

                  Benzo(a)Anthracene                                < 0.05             < 0.07              < 0.06              < 0.06

                  Chrysene                                          < 0.06             < 0.09              < 0.07              < 0.07

                  Benzo(b)Fluoranthene                              < 0. 14            < 0. 19             <0.15               < 0. 15

                  Benzo(k)Fluoranthene                              < 0. 13            <0.18               < 0. 15             < 0. 15

                  Benzo(a)Pyrene                                    <0.10              < 0. 14             <0.11               <0.11

                  Indeno(1,2,3-c,d)Pyrene                           <0.13              <0.17               < 0. 14             < 0. 14

                  DiBenzo(a,h)Anthracene                            < 0.28             < 0.38              < 0.30              < 0.31

                  1 PNA's                                           ---                ---                 ---                 ---


                  TEH                                               2.45               0.28                2.92                1.70


                  All concentrations reported as gg/mL. Figures reported are the mean (standard deviation) of
                            three replicate injections except where indicated.

                  TEH = total extractable hydrocarbons; determined gravimetrically and reported as Ag/mL.

                  < = indicates the compound was not detected at the given minimum detection quantity.









M                                                                                 69









                Table 3.7. Results of organic analyses of Cheatham Annex water samples.


                                                          SW-5(9/3)       SW/6(9/3)        SW-8(9/3)        SW-9


                Naphthalene                               <0.13           0.25a            < 0. 14          <0.16

                Acenaphthylene                            < 0.24          < 0.31           < 0.25           < 0.29

                Fluorene                                  < 0.03          < 0.04           < 0.03           < 0.03


                Phenanthrene                              < 0.02          < 0.02           < 0.02           < 0.02


                Anthracene                                < 0.02          < 0.02           < 0.02           < 0.02


                Fluoranthene                              < 0.02          < 0.02           < 0.02           < 0.02

                Pyrene                                    <0.01           <0.01            <0.01            <0.01

                Benzo(a)Anthracene                        < 0.03          < 0.04           < 0.03           < 0.04

                Chrysene                                  < 0.04          < 0.05           < 0.04           < 0.04

                Benzo(b)Fluoranthene                      < 0.08          <0.10            < 0.08           < 0.09

                Benzo(k)Fluoranthene                      < 0.07          <0.10            < 0.08           < 0.09

                Benzo(a)Pyrene                            < 0.06          < 0.07           < 0.06           < 0.07

                Indeno(1,2,3-c,d)Pyrene                   < 0.07          < 0.09           < 0.07           < 0.09

                DiBenzo(a,h)Anthracene                    < 0. 16         < 0.20           < 0. 16          <0.19

                I PNA's                                   ---             0.25             ---              ---


                TEH                                       0.11            1.50             1.13             0.83


                All concentrations reported as gg/mL. Figures reported are the mean (standard deviation) of
                       three replicate injections except where indicated.

                TEH = total extractable hydrocarbons; determined gravimetrically and reported as Ag/mL.

                a  compound detected in only one chromatogram

                <    indicates the compound was not detected at the given minimum detection quantity.








                                                                      70








                Table 3.8. Results of organic analyses of Cheatham Annex water samples.


                                                            SW-10            SW_llb            LW-1+LW-0LW-2+LW-2r


                Naphthalene                                 0.37a            0.19              0.23             0.16
                                                                                                                (0.00)
                Acenaphthylene                              0.47             0.39              0.51             < 0.28
                                                            (0.04)
                Fluorene                                    0.17a            0.08              < 0.03           < 0.03


                Phenanthrene                                0.11             0.09              0.11             < 0.02
                                                            (0.06)
                Anthracene                                  0.3a             0.07              0.06             < 0.02


                Fluoranthene                                0.16             0.3               0.34             < 0.02
                                                            (0-05)
                Pyrene                                      0.48 a           0.18              0.12             <0.01

                Benzo(a)Anthracene                          0.16             0.52              0.05             < 0.04
                                                            (0.10)
                Chrysene                                    0.32a            0.22              < 0.04           < 0.04

                Benzo(b)Fluoranthene                        <0.14            0.08              < 0.08           < 0.09

                Benzo(k)Fluoranthene                        < 0. 13          0.09              < 0.08           < 0.09

                Benzo(a)Pyrene                              <0.10            0.06              < 0.06           < 0.07

                Ind eno (1,2,3-c, d)Pyrene                  0.17             0.18              < 0.07           < 0.08
                                                            (0.06)
                DiBenzo(a,h)Anthracene                      0.34             <0.16             < 0. 16          < 0. 18
                                                            (0.08)

                I PNA's                                     1.88             2.45              1.42             0.16
                                                            (0.99)

                TEH                                         0.10             0.29              1.41             2.22


                All concentrations reported as Ag/mL. Figures reported are the mean (standard deviation) of
                         three replicate injections except where indicated.

                TEH = total extractable hydrocarbons; determined gravimetrically and reported asUg/mL.
                a = compound detected in only one chromatogram.
                b =  all compounds reported were detected in the same single chromatogram and were not
                         detected in the two other replicate injections.

                < = indicates the compound was not detected at the given minimum detection quantity.



                                                                         71









                  Table 3.9. Results of organic analyses of Cheatham Annex water samples.


                                                                             UVAPZ-4                       UVALP-3


                  Naphthalene                                                < 0. 15                       0.37
                                                                                                           (0.01)
                  Acenaphthylene                                             < 0.27                        0.52
                                                                                                           (0.01)
                  Fluorene                                                   < 0.03                        < 0.06


                  Phenanthrene                                               < 0.02                        < 0.03


                  Anthracene                                                 < 0.02                        < 0.04


                  Fluoranthene                                               < 0.02                        < 0.04

                  Pyrene                                                     <0.01                         < 0.02

                  Benzo(a)Anthracene                                         < 0.03                        < 0.06

                  Chrysene                                                   < 0.04                        < 0.08

                  Benzo(b)Fluoranthene                                       < 0.09                        < 0. 17

                  Benzo(k)Fluoranthene                                       < 0.08                        < 0. 16

                  Benzo(a)Pyrene                                             < 0.06                        < 0. 12

                  Ind eno(1,2,3-c,d)Pyrene                                   < 0.08                        <0.15

                  DiBenzo(a,h)Anthracene                                     <0.17                         < 0.33

                  I PNA's                                                    ---                           0.89


                  TEH                                                        2.06                          4.63




                  All concentrations reported as Ag/mL. Figures reported are the mean (standard deviation) of
                            three replicate injections except where indicated.

                  TEH = total extractable hydrocarbons; determined gravimetrically and reported asug/mL.
                  Water samples UVAPZ-4 and UVALP-3 were filtered through Whatman *1 qualitative filters.
                            The aqueous filtrates retained these sample IDs and received treatment similar to all
                            other water samples. The solids retained by the filter were designated UVAPZ-4s and
                            UVALP-3s, respectively, and received treatment similar to all other sediment samples.

                  < = indicates the compound was not detected at the given minimum detection quantity.



                                                                                  72






                                                            Figure 3.1
                                               67                           SAMPLING LOCATIONS
                                                               IV                      ORGANICS
                                                      68
                                                           Sludge
                         N0jR                              Pit


                                                          S-








                                                                 SW-6                   I *ter
                                                                                          arctcr
                                                                                         No. 1


                                                                                I    S-    UVALP 3
                                                                              W-.,,        Lw--@2 \@,
                                                                                       S-6      S-5
                                                                                      all/water
                                                                         UVAPZ-4          Ir


                                               57   10,

                                                             Bldg.
                                                             141
                                                                                     S

                                                                                   S


                                                                                      40)
                                                                                                                 3w-9


                                                                                                               S-1

                                               Sw- 11 Ournp                     sw-10
                                                                               F
                                            S-3 0\\                            S-Y


                   LEGEND


                   ES1 WELL


              0    UVA PIEZOMETER

                   SEDIMENT SAMPLE                                              CHEATHAM ANNEX PROJECr
                                                                        Department of Environmental Sc@e-ces
                   SURFACE WATER                                                   University of Virginia
                   SAMPLE                   (Taken from: ES 1, 1989)                 December 1, 1990

                                                                73









                                                     IV. METALS



                                                    IVA. Introduction


                     It has been shown that the Cheatham Annex site is contaminated by inorganic substances

              as well as organic substances. Previous chemical analyses performed on the Cheatham Annex site

              indicate the presence of metal contamination (ESI, 1989). ESI's analyses of soil borings and

              surface water samples revealed very little inorganic contamination. They detected heavy metal

              contamination above background levels, however, in 4 out of 8 sediment samples collected at the

              surface water sites and in most (10 out of 16) of their groundwater samples (Table 4.1).

              Particularly, ESI measured concentrations above the current groundwater maximum

              contamination limit (MCL) as didctated by EPA for arsenic, cadmium, chromium, and lead in

              many of their groundwater samples.

                     Four regions of concern can be isolated from the ESI report. The highest recorded levels

              of metals contamination were present in the groundwater samples collected from the berm at the

              northern (inflow) end of Hipps Pond. The samples were taken near an oil/water separator

              located in the berm. Another area of high metals concentration was located around the other

              oil/water separator on the southern side of the pond. A third region of groundwater

              contamination is located near the sludge pit alongside the North Branch of Hipps Creek. Finally,

              metals were also detected at locations in the upper portion of the South Branch of Hipps Creek.

                     We chose our sampling sites based on these previous findings and proximity to our

              hydrologic studies. We monitored those wells from which ESI had measured particularly high

              metals concentrations the previous year in order to evaluate any changes. We also installed new

              wells and sampled new surface water locations which gave us a more in-depth chemical

              characterization of specific areas of concern on the site.








                                                              74










                                                     1VB. Methods


                                                  Sampling Philosophy


                    We chose to concentrate our sample collection sites for metals over three regions of

            investigation. Focusing on the area of the North Branch of Hipps Creek, we sampled surface

            water, groundwater, and sediments (Fig. 4.2). We also sampled surface and groundwater entering

            Hipps Pond, surface water and sediments in the pond itself, and surface-water outflow from the

            pond (Fig. 4.1). The third region of sampling was on the southern side of the pond where various

            groundwater samples were collected. The nature and location of all samples collected for metals

            analysis are summarized in Table 4.2. All samples are described in Appendix L

                    Sampling locations along the North Branch were chosen to give us a more comprehensive

            understanding of the contamination of different media in this area. Previous analyses by ESI

            indicated high concentrations of metals in the groundwater below sludge pit #1. In particular, we

            hoped to characterize a plume of contamination which may be extending from the dumping area

            towards the stream. Sediments and groundwater downgradient of this pit were collected as well

            as surface water samples in the North Branch. Groundwater was collected from monitoring well

            MW-7 which had been installed and monitored by ESI in 1989. Two additional wells were

            installed and monitored at the margin of the floodplain and on the floodplain. One sediment

            sample was collected on the floodplain. Surface samples were taken at five points along the

            stream both upstream and downstream of the sludge pit.

                    Sampling locations in the vicinity of Hipps Pond were chosen to monitor and further

            characterize the contamination of the pond and to attempt to locate any possible point sources of
            contamination. In previous work by ESI, the highest levels of metal contamination' were found in

            a deep well installed next to an oil water separator in the man-made berm at the northern edge of

            the pond near the inflow. Samples of all types and media were collected in and around Hipps

            Pond. Groundwater and surface water inflow locations were sampled at various points along the

            pond margin. Groundwater samples were collected from MW-5, the monitoring well which had


                                                             75








             such high levels of contamination reported by ESI. This well is located very close to the inflow

             culvert from the North and South Branch streams. A surface water sample was collected before

             the stream entered the berm, and another as the stream emerged in Hipps Pond on the other

             side. Groundwater samples were also collected from a lakeside piezometer located downgradient

             of the other oil water separator to further monitor groudwater inflow to the pond. Surface and

             sediment samples were also collected from the pond itself. We sampled both the shallower inflow

             end of the pond as well as the sediments and surface water of the deeper, mid-pond region. We

             also sampled sediments on the pond margin near our groundwater collection sites on the south

             side. We monitored the surface water outflow from the pond.

                     The final region of investigation was the area surrounding the other oil water separator

             located on the south side of the pond. As in the previous regions of study, we were interested in

             more specific information on the chemical composition of the water in this area than had

             previously been available. Groundwater samples were collected at MW-6, a monitoring well from

             which ESI had also collected samples and recorded high levels of metals. Another groundwater

             sample was collected downgradient of the pit closer to the pond margin.


                                        Collection of Samples for Metals Analysis


             Water Samples


                     The surface water samples were collected by submerging sampling jars 1-5 cm below the

             surface. The jars were filled completely so no head space remained. All water samples collected

             for heavy metal analysis were stored in 0.5 L teflon coated clear glass jars sealed with aluminum

             foil and screw tops. The samples were placed in an ice-filled cooler and later stored under

             refrigeration prior to analysis. During the sampling procedure ubber gloves were worn at all times.

                     The pond water sample was collected before the sediment samples in each location were

             collected. This prevented contamination of the water sample by agitated bottom sediments.

                     Groundwater samples were collected from wells installed at least three weeks previous to

             the collection date (see section IIC of this report for well installation details). A minimum of

                                                               76









             three well volumes of water were evacuated from each well prior to sampling. Most samples were

             collected using a stainless steel WILCO sampler which was rinsed with deionized water before

             each sample was collected. Sample LP-5 was collected from a one inch piezometer which was too

             small for the Wilco sampling device; this sample was collected using a Nalgene hand pump fitted

             with Tygon tubing. Sample jars were filled as completely as possible.


             Sediment Samples


                     The pond sediment samples were collected using a steel Wilco sediment bucket sampler.

             Samples were collected to a depth of 10 cm below the sediment-water interface. During sampling

             rubber gloves were worn at all times. The bucket was rinsed after each sample was collected.

                     The pondside sediment sample was collected using a hand auger which collected to a

             depth of 15 cm. The North Branch floodplain sediment sample was collected using a shovel to a

             depth of 5 cm.

                     All sediment samples were placed in sealable plastic bags from which as much air as

             possible was removed. The samples were placed in a cooler filled with ice and frozen immediately

             upon return to the lab.


                                                         Analysis


                     The water samples and the sediment samples were submitted for analysis to Mike

             Lockhart at Havens Laboratory in Charlottesville, VA. The water samples were analyzed for six

             metals: chromium, silver, cadmium, barium, mercury, and lead. Contrary to our request the

             report from Havens Laboratory did not include results from arsenic analysis. No analyses of the

             sediment samples were returned to us. No information on the methods of chemical analysis or of

             sample treatment prior to analysis was made available to us.







                                                             77









                                                         IVC. Results


                      The results of the chemical analysis are listed in Table 4.3. The concentrations of four of

              the six metals, silver, cadmium, mercury, and lead, were below the detection limit of analysis in all

              water samples. For simplification we have listed a summary of the detected metals concentrations

              in Table 4.4.

                      Detectable chromium concentrations ranged from 0.011 mg/L to 0.014 mg/L and were

              found in both groundwater and suface water samples. All of the measured concentrations were

              less than the maximum contamination limit set by EPA of 0.04 mg/L. The highest chromium

              concentrations were found in groundwater samples ESIMW-5 and UVANW-14. There does not

              seem to be any identifiable areas of the site represented by the samples with detected

              concentration levels as these samples are located in nearly every sampling region.

                      Detectable barium concentrations ranged from 0.31 mg/L to 0.34 mg/l and were found in

              only three locations: the surface water of Hipps Pond collected at mid-pond and groundwater

              sampling locations UVALP-5 and ESIMW-5. The highest concentrations were found in ESIMW-

              5. None of these concentration values were higher than the maximum concentration limit set by

              the EPA of 5 mg/L.

                      We reported detectable levels of both barium and chromium in one groundwater location,

              ESIMW-5. This well is located on the inflow berm of Hipps Pond near an ofl/water separator.


                                                        lVD. Discussion


                      The concentration of metals in the groundwater samples collected in the present investiga-

              tion was very low (Tables 4.3 and 4.4). Our results indicate that there is no significant metals

              contamination in the areas we sampled. This finding is in dramatic contrast to the results report-

              ed by ESI in 1989 (Table 4.1).

                      We are uncertain what these results mean. It seems unlikely that there would be such a

              large reduction in these metal concentrations in one year. Having only one suite of samples from

              each study, though, does not allow us to evaluate whether present or antecedent hydrologic

                                                                 78











             conditions influence the concentrations we observe. Several observations need to made over time

             in order to evaluate the reality of metals contamination at this site.

                     We do not have adequate information on sample collection, treatment, preservation, and

             analysis methods employed in the two studies to even feel confident that either group has

             reported real values of dissolved metals concentrations in the groundwater at the Cheatham

             Annex site.

                     ESI (1989) did not filter their groundwater samples before acidification. Thus dissolution

             of any suspended particles in the groundwater (clay, silt-sized grains, etc.) would have contributed

             to the metals concentrations determined in the laboratory. We would expect that the solid phase

             would be relatively concentrated in metals relative to the aqueous phase, and the acid dissolution

             of a small mass of suspended material could make a significant contribution to the analyzed metal

             concentration. Our experience in collecting groundwater at the site is that it appears turbid upon

             collection and these suspended sediments settle out of the sample as it sits in the sample bottle.

                     Water Samples for this report were collected under the supervision of Mike Lockhart.

             Groundwater samples were collected, stored in bottles, and kept on ice. They were not filtered;

             they were not acidified in the field. Havens laboratory was unavailable to comment on whether

             the samples were filtered or acidified after return to the laboratory. It is also not clear how long

             the samples were stored prior to analysis.

                     Analysis of trace metals requires not only careful analytical work, but special precautions

             taken in the collection, preservation, and storage of samples. The Environmental Protection

             Agency, the American Public Health Association, and the U.S. Geological Survey, to mention a

             few, have published recommended guidelines for such work. Some common recommendations

             include immediate filtering and acidification of water samples upon collection. These steps must

             be taken before change in pH or oxidation state of the sample itself, usually through exposure to

             the atmosphere, cause changes in the saturation state of the water. Any dissolution of solid phase
             before the solution is preserved would result in a misrepresentation of in situ groundwater

             composition by analytical methods. In situ metals composition would also be misrepresented if

                                                               79









             precipitation from the sample occurred without subsequent acidification. Adequate care was

             simply not taken in the previous or the present study of the groundwater Cheatham Annex. The

             magnitude and extent of metals contamination of the subsurface water at this site are simply not

             known.



                                                     IVE. Summary


                    The major points for summary from our study of the metals contamination of the

             Cheatham Annex site follow.

                 1) Because of deficiencies in the studies to date, the extent and magnitude of metals

                     contamination is unknown.











































                                                             80








               Table 4.1. Summary of metals analyses reported by ESI (1989). All concentrations are expressed
               in mg/L. Listed are groundwater samples with metal concentrations which exceed both the
               maximum contamination limit (MCL) and background concentration (MW-1).


               Well     Cr         Cd       As     Pb          Description



               MW-2       0.16    ---     ---     ---          alongside North Branch, upstream of sludge pit

               MW-5       1.51    0.077   0.91    0.41         inflo'w berm to Hipps Pond at oil/water separator #1
                 rep.     1.29    0.075   0.92    0.37

               MW-6       0.30    0.021   0.101   0.07         south of Hipps Pond, near oil/water separator #2

               MW-7       0.10     ...    0.10    ---          alongside North Branch, below sludge pit

               MW-9       0.25     ---    0.16    ---          near swamply inflow to Hipps Pond

               MW-10      0.27     ---    0.12    ---          uphill of inflow berm to Hipps Pond

               MW-12      0.13     ---    0.07    ---          inflow berm to Hipps Pond

               MW-13      0.20     ---    0.12    ---          south of Hipps Pond, at oil/water separator

               Pz- 1      0.10     ---    0.10    ---          South Branch, far upstream

               PZ-4       0.31     ---    0.16    ---          South Branch, far upstream


               MCLa       0.05    0.01    0.05    0.05

               MW_lb      0.09     ---    0.04    ---          north of Perimeter Road North


               a = current groundwater maximum contamination limit (MCL) dictated by EPA.
               b =  groundwater collected away from sites of known contamination; taken to be representative of
                       background groundwater composition















                                                                    81








             Table 4.2. Information on the nature of the samples collected for metals analyses.


             ID          Date        Figure   Location


             Hipps Pond Surface Water

             LW-2         7/31       4.1      Hipps Pond, mid-pond
             LW-3         7/2        4.1      Hipps Pond, at inflow culvert
             LW-3r        7/24       4.1

             Surface Water

             SW-1         7/24       4.2      North Branch, at NW-12 (station 4a)
             SW-2         7/24       4.2      North Branch, below NW-13 (station 8a)
             SW-3         7/24       4.2      North Branch, across from NW-15 (station 10a)
             SW-3r        7/24       4.2
             SW-4         7/24       4.2      North Branch, downstream of NW-15
             SW-5         7/24       4.2      North Branch, before confluence with South Branch
             SW-7         7/24       4.1      Hipps Creek, just before culvert
             SW-8         7/24       4.1      Hipps Pond, outflow before flume

             Groundwater

             UVALP-5      7/31       4.1      pondside, downgradient of oil/water separator #2
             ESIMW-5      7/24       4.1      inflow berm to Hipps Pond at oil/water separator #1
             ESIMW-5r     7/24       4.1
             ESIMW-5      7/31       4.1
             ESIMW-5r     7/31       4.1
             ESIMW-6      7/31       4.1      south of Hipps Pond, near oil/water separator #2
             ESIMW-6r     7/31       4.1
             ESIMW-7      7/24       4.2      alongside North Branch, below sludge pit
             ESIMW-7r     7/24       4.2
             UVANW-14     7/31       4.2      perimeter North Branch floodplain below sludge pit
             UVANW-15     7/31       4.2      North Branch floodplain, below sludge pit
             ESIPZ-2      7/31       4.1      downgradient of oil/water separator #2


             Key to meaning of sample names:

             "S" = sediment/soil sample
             "LW" = pond water sample
             '
              SW" = surface water sample
             "'LP" = groundwater sample from lake piezometer
             "PZ" = groundwater sample from piezometer
              MW" or "NW" = groundwater sample from monitoring well
             Y = replicate







                                                           82








               Table 4.3. Results of metals analyses. All concentrations are expressed as mg/L.

                            Sampling
               ID              Date             Cr            Ag           Cd            Ba           Hg            Pb


               SW-1            7/24               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-2            7/24               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-3            7/24             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-3r           7/24             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-4            7/24               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-5a           7/24
               SW-7            7/24               0.012       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               SW-8            7/24               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               LW-2            7/31             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               LW-3            7/24               0.012       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               LW-3r           7/24             <0.01         < 0.02       < 0.003        0.32        < 0.0002     <0.01

               ESIMW-5         7/24             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               ESIMW-5r        7/24             <0.01         < 0.02       < 0.003        0.31        < 0.0002     <0.01
               ESIMW-5         7/31               0.014       < 0.02       < 0.003        0.32        < 0.0002     <0.01
               ESIMW-5r        7/31               0.012       < 0.02       < 0.003        0.34        < 0.0002     <0.01
               ESIMW-6         7/31             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               ESIMW-6r        7/31               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               ESIMW-7         7/24             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               ESIMW-7r        7/24             <0.01         < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               ESIPZ-2         7/31               0.011       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               UVALP-5         7/31               <0.01       < 0.02       < 0.003        0.32        < 0.0002     <0.01
               UVANW-147/31                       0.014       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01
               UVANW- 15 7/31                     <0.01       < 0.02       < 0.003       < 0.3        < 0.0002     <0.01


                    insufficient sample to analyze





















                                                                           83








              Table 4.4. Summary of detected metals. Concentrations are expressed as mg/L.

                                          Cr          Ba              Description


              SW- 1                  0.011      ---           North Branch, at NW-12 (station 4a)
              SW-2                   0.011      ---           North Branch, below NW-13 (station 8a)
              SW-4                   0.011      ---           North Branch, downstream of NW-15
              SW-7                   0.012      ---           Hipps Creek, just before culvert
              SW-8                   0.011      ---           Hipps Pond, outflow before flume
              LW-3r                 ---           0.32        Hipps Pond, at inflow culvert
              ESIMW-5r(7/24)        ---           0.31        inflow berm to Hipps Pond at oil/water separator
              ESIMW-5(7/31)          0.014        0.32
              ESIMW-5r(7/31)         0.012        0.34
              ESIMW-6r               0.011      ---           south of Hipps Pond, aside sludge pit #2
              ESIPZ-2                0.011      ---           downgradient of sludge pit #2 and oil/water
                                                                      seporator
              UVANW-14               0.014      ---           perimeter of North Branch floodplain below sludge
                                                                      pit #1
              UVALP-5               ---           0.32        pondside, downgradient of sludge pit #2 and
                                                                      oil/water separator

              Detection
              Limit                  0.01         0.3



                    below detection limit


































                                                                  84





            Figure 4.1
                                                                                 HIPPS POND
                                                                        SAMPLING LOCATIONS
                                                                                    METALS

                                                ESIMW-5

                                                              01 I/Water Separator -I


                         sw-                                                          LEQENQ

                                      to                                              ESI WELL
                                     LW-3                                        0    UVA PIEZOMETER

                                                                                      SEDIMENT SAMPLE


                                                                                      SURFACE WATER
                                                                                      SAMPLE








                                                UVAL -5



                            jowwater        ESIPZ-2
                            Seperator'12



                                                                           LW-2







                           E
                            S
                             IMW-6









                                                                                               SW-8






                    SCALE
                                                                           CHEATHAM ANNEX PROJECT
                                                                    Department of Environmental Science
                                    M      GENERAL CONTOUR                    University of Virginia
            30         0        30        INTERVALIN METE&                       December 1, 1990







                                Figure 4.2


               NORTH AND SOUTH BRANCH
                    SAMPLING LOCATIONS                                                                                       Sw-5
                                 METALS


                                                                          Sludge Pit
                                                                       Ir                        Sw-



                                                                       ESIMW-
                                                                                YANW
                     LEGEND                                           UVA W- 146   0Sw-
                     ESI WELL

                                                                                                                             South Branc
                0    UVA PIEZOMETER                    North Branch

         C
         C)    jo    SEDIMENT SAMPLE

                     SURFACE WATER
                     SAMPLE
                                                 wl







                                Sw-i







                                                                                                                    CHEATHAM AN
                                                                                                             Department of Envir
                                A
                                                                                                                        University 0
                                                                                                                          December









                                                    V. DISCUSSION


                     The primary objective of our research at Cheatham Annex was to identify the major
             components driving the hydrology of the site, and characterize the organic and heavy metal

             contamination in the areas most strongly affected by hydrological forces. Based on the results of

             our chemical analyses, significant organic contamination was not found in the surface waters of

             the site, nor in two groundwater samples from the south side of the pond. We cannot make any

             conclusions about heavy metal contamination due to possible laboratory errors. Nevertheless, the

             organic data provide an indicator of the water quality status in hydrologically critical areas at the

             site.

                     Our conclusions from the hydrological research at the site demonstrated the dominance of

             base-flow surface water on the overall site water budget through Hipps Pond. These inputs are

             derived from the entire site area and are continually delivered to the Pond at an times. It is likely

             that base-flow chemistry, with regards to organic contamination, would not significantly differ

             over the course of several seasons. The factors affecting the magnitude of surface water input are

             mainly PET in the hillslope soils and recharge to the creek contributing areas. Although base-flow

             rates will fluctuate seasonally, considerable changes in the nature of the waters would not be

             expected.

                     These inferences allow the results of the organic analyses to be cast into a broader

             framework. It is likely that base flows into Hipps Pond will continue to be dilute with respect to

             organics through the seasons. As base flow drops and portions of each creek from the headwater

             areas towards downstream cease to flow, the relative input from drainage areas containing

             storage tanks changes, but analyses of groundwater samples indicate that large changes in PNA

             concentrations in the stream are unlikely.

                     Generally, all tanks are located in the headwater regions of the creeks, and also line one

             side along the creeks' lengths (Figure 2.1). Contributions from the headwater areas are greatest

             during the high base-flow periods of the early summer. We did not observe any systematic change

             in organic concentrations over the course of the field season, suggesting that the contributions of

                                                                87









             potentially contaminated inflow areas does not change over time.

                     However, these results can not be extrapolated through time because of the potential

             influence of radically changed flow conditions during spring high-flow conditions. Furthermore,

             contaminants in the groundwater may move very slowly because of the flat gradients. Thus, it is

             possible that some plume of contamination, which our survey did not identify, may break through

             and contaminate surface waters. For example, several "hot spots" of organic contaminants have

             been identified (ESI, 1989), but no data are available about the lateral or vertical extent of

             contaminants. A more complete characterization of the spatial distribution of contaminants, the

             groundwater flow rates, and the adsorption properties of the soils would greatly improve our

             ability to assess the potential for mobilization and off-site migration of contaminants. Our results

             can be used only for short time-scale assessment of contaminant migration during base-flow

             conditions.

                     These observations do not imply that contaminants are not present in the areas we

             sampled. Previous investigations have indicated that sediments in many areas contain dispropor-

             tionate concentrations of organic compounds relative to the water with which they are in contact

             (ESI, 1989). It is likely that chemical factors govern the movement of the contaminants, and base

             flow hydrological processes play a secondary role.

                     The sediment sample collected from the floodplain of the North Branch did not contain

             significant concentrations of organics. Floodplain sediments and stream channel sediments are

             the most mobile and unstable materials in a catchment. The areas in which they occur were shown

             to be the major sources of response water during storms. Due to the interplay between chemical,

             hydrological, and geomorphological processess, the single sediment sample may not necessarily be

             "representative" of floodplain sediments in general.

                     Based on steep near-stream lateral and vertical gradients related to storms, storm flow is

             predominantly comprised of floodplain and bank water displace during these events. Immobilized

             contaminants concentrated at the stream margins may enter the stream, resulting in increased

             migration during storms. Consequently, storm flow, rather than base flow, could potentially carry

                                                               88









              the bulk of contaminants to Hipps Pond. This conclusion suggests that although base flow is the

              major hydrological inflow component to Hipps Pond, storm flow might be the most significant

              component related to contaminant transport to Hipps Pond.

                     The role of storms in delivering short-lived but high concentration pulses of contaminants

              to the pond is a possibility that clearly warrents further consideration. We were unable to collect

              pond or creek surface water samples during or following large storms. Field observations

              following storm events indicated however, that significant amounts of sediment are moved

              downchannel, and considerable scour occurs in the bottom of Hipps pond. Organic compounds

              with low aqueous solubilities may tend to move with sediment particles during storm events.

              These sediments could be drawn from along the entire reach of the creeks. Upon reaching the

              pond, sediments, and the associated organics, would settle out.

                     Overall, our investigation of the contamination of the surface and near surface waters

              indicates that generally concentrations of organics are low under base flow conditions. Over the

              seasonal cycle, surface water concentrations would not be expected to change considerably. To

              extend our base-flow observations to a larger time-scale, further investigations should be under-

              taken to examine the distribution of contaminants over the entire site, and along flow-paths to the

              creeks.



























                                                               89









                              VI. CONCLUSIONS AND RECOMMENDATIONS


              1) Any soluble subsurface contamination that is mobilized in the vicinity of the storage tanks, the

                  discarded drums, the cosmoline dump, and so forth will move down gradient in the shallow

                  groundwater and flow toward local streams and/or toward King's Creek and the York River.

              2)  No major areas of contamination, other than sediments of Hipps Pond, were discovered in our

                  study. There is large uncertainty, however, regarding the magnitude and extent of

                  undiscovered contamination of soils and groundwater. There is also great uncertainty

                  regarding the possible fate and transport of any contamination at the Cheatham Annex site.

              3)  Further work is required to

                      a) characterize the inflow and outflow of contaminated water in Hipps Pond during winter

                         and spring high-flow conditions;

                      b) accurately determine the magnitude and extent of metals contamination at the site;

                      c) assess the extent of the contamination of soils by organic contaminants and characterize

                         the soil/water partitioning of those organics; and

                      d) determine the rates of sediments in Hipps Pond and the biodegradation rates of

                         organic contaminants in the sediments.






















                                                                90









                                               V11. REFERENCES


             Cherry, R.A., 1974. Strearnflow generation. Reviews in Geophysics and Space Physics. 12: 627-
                    646.

             Engineering-Science, Inc., 1989. Site Investigation Report, Commonwealth of Virginia Emergency
                    Fuel Storage Facility, York County, Virginia. Preliminary draft.

             Freeze, R.A. and A. Cherry, 1979. Groundwater. Prentice-Hall, Englewood Cliffs, N.J.

             Hamon, W.R., 1961. Estimating potential evapotranspiration. Journal of Hydraulics Division of
                    the Proceedings of the American Society of Civil Engineers. 87: 107-210.

             Kol1a, E., 1987. Estimating storm peaks from small rural catchments in Switzerland. Journal of
                    Hydrology. 95: 203-225.

             McIntyre, P.E., 1988. Groundwater Seepage And Sulfur Diagenesis In Acidified Lake Sediments.
                    PhD. dissertation, Department of Environmental Sciences, University of Virginia.

             Winter, T.C., 1981. Uncertainties in estimating the water balance of lakes. Water Resources
                    Bulletin. 17: 82-112.







































                                                            91









                                                  VIII. APPENDICES


                                              Appendix 1. Nature of Samples



              ID           Date        Anal.      Figure    Location


              Hipps Pond Surface Water

              LW-1         8/2         Org.       3.1       Hipps Pond, 7 m from inflow
              LW-Ir        8/2         Org.       3.1
              LW-2         7/31        H.M.       4.1       Hipps Pond, mid-pond
              LW-2         8/2         Org.       3.1
              LW-2r        8/2         Org.       3.1
              LW-3         7/24        H.M.       4.1       Hipps Pond, at inflow culvert
              LW-3r        7/24        H.M.       4.1

              Sediments

              S-1          9/3         Org.       3.1       perimeter north of Diesel Dr.
              S-2          9/3         Org.       3.1       perimeter south of Diesel Dr.
              S-3          9/3         Org.       3.1       perimeter downgradient of cosmoline dump
              S-4          8/2         Org.       3.1       Hipps Pond, 7 m from inflow
              S-5          8/2         Org.       3.1       Hipps Pond, mid-pond
              S-6          8/2         Org.       3.1       Hipps Pond, pond margin
              S-7          8/2         Org.       3.1       North Branch floodplain, at NW-14
              S-7r         8/2         Org.       3.1

              Surface Water

              SW-1         7/24        H.M.       4.2       North Branch, at NW-12 (station 4a)
              SW-2         7/24        H.M.       4.2       North Branch, below NW-13 (station 8a)
              SW-3         7/24        H.M.       4.2       North Branch, across from NW-15 (station 10a)
              SW-3r        7/24        H.M.       4.2
              SW-4         7/24        H.M.       4.2       North Branch, downstream of NW-15
              SW-5         7/24        H.M.       4.2       North Branch, before confluence with South Branch
              SW-5         8/2         Org.       3.1
              SW-5         9/3         Org.       3.1
              SW-6         8/2         Org.       3.1       South Branch, before confluence with North Branch
              SW-6         9/3         Org.       3.1
              SW-7         7/24        H.M.       4.1       Hipps Creek, just before culvert
              SW-8         7/24        H.M.       4.1       Hipps Pond, outflow before flume
              SW-8         8/2         Org.       3.1
              SW-8         9/3         Org.       3.1
              SW-9         9/3         Org.       3.1       perimeter north of Diesel Dr.
              SW-10        9/3         Org.       3.1       perimeter south of Diesel Dr.
              SW-11        9/3         Org.       3.1       perimeter downgradient of cosmoline dump
              SW-12        8/2         Org.       3.1       swampy inflow to Hipps Pond




                                                                92









            ID           Date       Anal.      Map ID Location


            Groundwater

            UVALP-3      10/9       Org.       3.1      pondside, downgradient of oil/water separator #2
            UVALP-5      7/31       H.M.       4.1      pondside, downgradient of oil/water separator #2
            ESIMW-5      7/24       H.M.       4.1      inflow berm to Hipps Pond at oil/water separator #1
            ESIMW-5r     7/24       H.M.       4.1
            ESIMW-5      7/31       H.M.       4.1
            ESIMW-5r     7/31       H.M.       4.1
            ESIMW-6      7/31       H.M.       4.1      south of Hipps Pond, near oil/water separator #2
            ESIMW-6r     7/31       H.M.       4.1
            ESIMW-7      7/24       H.M.       4.2      alongside North Branch, below sludge pit
            ESIMW-7r     7/24       H.M.       4.2
            UVANW-147/31            H.M.       4.2      perimeter North Branch floodplain below sludge pit
            UVANW-157/31            H.M.       4.2      North Branch floodplain, below sludge pit
            ESIPZ-2      7/31       H.M.       4.1      downgradient of oil/water separator #2
            UVAPZ-4 10/9            Org.       3.1      upgradient of swampy inflow to Hipps Pond

            Suspended Solids

            LP-3s        10/9       Org.       3.1      pondside, downgradient of oil/water separator #2
            PZ-4s        10/9       Org.       3.1      upgradient of swampy inflow to Hiips Pond


            Key to meaning of sample names:

            "S" = sediment/soil sample
            "LW" = Pond water sample
            "SW" = surface water sample
            TP" = groundwater sample from lake piezometer
            "PZ" = groundwater sample from piezometer
            IVMWIV or "NW" = groundwater sample from monitoring well
            "r" = replicate
             s" = solids which were filtered from the water sample

















                                                            93








                           Appendix 2. Water Level Measurements - UVA Wells


          Appendix 2. summary of water level measurements from UVA wells.
          All values expressed as absolute elevations above mean sea level.

          Date             6/6     6/13     6/21       6/27       7/2
                        current current current current         current High
          UVA well         (m)       (m)     (m)       (m)        (m)       (m)


          UVANW-11                                      9.42      9.41
          UVANW-10                                      9.35      9.23    9.50
          UVANW-9                    9.62     9.20      9.29      9.29
          UVANW-8                    8.85     9.28      9.29      9.29    9.32
          UVANW-7                    9.34     9.30      9.34      9.33
          UVANW-6                    9.28     9.33      9.34      9.19    9.42
          UVANW-5          9.75      9.95     9.94      9.87      9.90
          UVANW-4          8.66      8.69     8.67      8.64      8.62    8.58
          UVANW-3          9.05      8.96     8.93      8.87      8.97
          UVANW-2          7.71      8.56     8.58      8.56      8.31    8.57
          UVANW-1                    8.50     8.31      8.33      8.29
          UVAPZ-1          3.81      3.83     3.81      3.82      3.80
          UVAPZ-2                    4.50     4.46      4.42      4.43
          UVAPZ-3                    3.04     3.46      3.41      3.38
          UVAPZ-4                             7.23      5.79      5.85
          UVALP-1                             3.55      3.49      3.70
          UVALP-2                             4.25      3.66      3.71
          UVALP-3                                       3.51      3.56
          UVALP-4                                       3.31      3.53
          UVALP-5                                                 3.60
          Lake level                                              3.45






























                                              94










           Date                7/9              7/12               7/18
                        Current High      Current High       Current     High
           UVA well      (M)     (M)         (M)    (M)       (M)        (M)



           UVA"-15                                                6.90    6.88
           UVAMW-14                                               7.69    7.66
           UVAMW-13                                               8.08    8.33
           UVAMW-12                                               8.69    8.65
           UVANW-11       9.38               9.38                 9.57    9.41
           UVANW-10       9.15    9.35       9.21    9.43         9.16    9.51
           UVANW-9        9,25               9.29                 9.47    9.49
           UVANW-8        9.23    9.29       9.22    9.36         9.44    9.46
           UVANW-7        9.33               9.34                 9.46    9.42
           UVANW-6        9.18    9.34       9.19    9.35         9.27    9.51
           UVANW-5        9.78               9.77                 9.83
           UVANW-4        8.60    8.64       8.62    8.63         8.63    8.84
           LTVANW-3       8.95               8.94                 9.19    9.03
           UVANW-2        8*28    8*43       8,30    8,57         8*30    8,62
           UVANW-1        8.32               8.31                 8.50    8.41
           UVAPZ-1        3.78               3.75                 3.77
           UVAPZ-2        4.37               4.34                 4.31
           UVAPZ-3        3.35               3.31                 3.26
           UVAPZ-4        5.79
           UVALP-1        3.74               3.74                 3.82
           UVALP-2        3.67               3.67                 3.63    3.73
           UVALP-3        3.53               3.60                 3.53    3.59
           UVALP-4        3.49               3.51                 3.60
           UVALP-5                           3.58                 3.57    3.68
           Lake level     3.42               3.43                 3.51
































                                                 95










                          7/24                  8/1             8/16
                       Current High       Current     High     Current      High
          UVA well        (M)      (M)         (M)     (M)       (M)        (M)


          UVAMW-15                 6.89      6.94      6.87       6.92      6.90
          UVAMW-14                 7.67      7.67      7.55       7.63      7.67
          UVAMW-13      8.09       8.02      7.98                 7.95      8.13
          UVMW-12       8.54       8.68      8.69                 8.43      8.54
          UVAMW-11      9.58       9.54      9.49      9.54       9.48      9.50
          UVAMW-10      8.97                 9.13      9.32       9.28      9.48
           UVAMW-9      9.42       9.30      9.25      9.38       9.31      9.42
           UVAMW-S      9.43       9.48      9.26      9.44       9.36      9.51
           UVAMW-7      9.52       9.37      9.33      9.46       9.39      9.44
           UVAMW-6      9.20       9.51      9.17      9.38       9.35      9.58
           UVAMW-5      9*75                           11.79      9.67
           UVAMW-4      8.61                 8.60      8.65       8.65      8.76
           UVAMW-3      9.18       9.07                10.45      9.18
           TJVAMW-2     8.32       8.65      8.30      8.60       8.47      8.59
           UVMW-1       8.45       8.43      8.42      8.44       8.41      8.44
           UVAPZ-1      3.75                 3.75                 3.68
           UVAPZ-2      4.29                 4.27                 4.19
           UVAPZ-3      3*24                 3.21                 3.13
           UVAPZ-4
           UVALP-1      3.77                                      3.75
           UVALP-2      3,72       3*78                3.68       3.59      3.75
           UVALP-3      3.48       3.56                3.50       3.50      3.61
           UVALP-4      3.56                                      3.70
           UVALP-5      3.53       3.98                3.59       3.46      3.69
          Lake level    3.46                 3.41                 3.48

































                                                96









                     8/24                9/4              9/14
                     Current High        Current High     Current High
          UVA well   (M)       (M)        (M)      (M)      (M)       (M)


          UVAMW-15    6.90      6.95                         6.91      6.91
          UVAMW-14    7.61      7.72                         7.49      7.67
          UVAMW-13    8.09      8.41      7.92      8.06
          UVAMW-12    8.46      8.47      8.32      8.43     8.38      8.43
          UVAMW-11    9.49      9.50      9.40      9.50     9.41      9.41
          UVAMW-10    9.35      9.47      9.15      9.31     9.10      9.31
           UVAMW-9    9.34      9.38      9.26      9.31     9.28      9.32
           UVAMW-8    9.28      9.48      9.21      9.30     9.26      9.32
           UVAMW-7    9.46      9.43      9.39      9.39     9.39      9.39
           UVAMW-6    9.35      9.45      9.22      9.38     9.37      9.34
           UVAMW-5    9.66                                   9.60
           UVAMW-4    8.69                                   8.65      8.77
           UVAMW-3    8.98      9.20      9.61                         8.99
           UVAMW-2    8.52      8.59      8.52
           UVAMW-1    8*39      8*44      8*37      8*39     8,34      8*37
           UVAPZ-1    5.39                3.63               3.62
           UVAPZ-2    4.18                4.13               4.09
           UVAPZ-3    3.09                3.04               3.01
           UVAPZ-4
           UVALP-1    3.92                3.77
           UVALP-2    3.66      3.73      3.61      3.72     3.80      5-.63
           UVALP-3    3*37      3,63      3,42      3,59     3*48      4,68
           UVALP-4    3.63                3.49               3.57
           UVALP-5    3.56      3.69      3.55      3.66     3.58      4.79
          Lake lev.   3.46                3.39               3.44
































                                              97









                            9/25                10/18
         UVA well           Current     High   Current    High
                              (M)         (M)    (M)        (M)


         UVAMW-15             6.84      6.97
         UVAMW-14             7.46      7.54
         UVAMW-13                                 7.80      8.01
         UVAMW-12             8.41      8.41      8.38      8.42
         UVAMW-11             9.33      9.41      9.28      9.38
         UVAMW-10             9.16      9.17      9.06      9.18
          UVAMW-9             9.27      9.28      9.27      9.28
          UVAMW-8             9.25      9.29      9.22      9.28
          UVM4W-7             9.37      9.37      9.30      9.32
          UVAMW-6             9.29      9.37      9.21      9.33
          UVANW-5
          UVAMW-4             8.55      8.62
          UVAMW-3                       8.94
          UVAMW-2             8.49      8.55      8.39      8.54
          UVAMW-l             8.39      8.36      8.34      8.36
          UVAPZ-1
          UVAPZ-2
          UVAPZ-3
          UVAPZ-4
          UVALP-1
          UVALP-2
          UVALP-3                       3.26
          UVALP-4
          UVALP-5                       3.61


































                                             98








                           Appendix 3. Water Level Measurements - ESI WelIs


          Appendix 3. Summary of water level measurements from ESI wells.
          All values expressed in absolute elevation above mean sea level.

          ESI Well     6/6      6/13      6/21     6/27       7/2       7/9      7/12
                       (m)        (m)




          ESI XW-4    9.45      9.35      9.31      9.27      9.25      9.18      9.21
          ESI NW-2    9.27      9.22      9.17      9.14      9.11      9.07      9.06
          ESI MW-7    7.93      7.88      7.83      7.79      7.79      7.72      7.69
          ESI XW-5    5.61      5.57      5.55      5.51      5.49      5.46      5.42
          ESI MW-12             5.71      5.68      5.64      5.62      5.58      5.56
          ESI NW-11             6.28      6.25      6.21      6.16      6.13      6.06
          ESI NW-10             6.79      6.73      6.69      6.63      6.56      6.53
          ESI NW-13   4.80      4.77      4.73      4.70      4.68      4.66      4.64
          ESI NW-9    5.13      5.09      5.06      5.02      5.01      4.96      4.96
          ESI NW-6    6.38      6.33      6.27      6.22      6.18      6.13      6.10
          ESI PZ-2    4.52      4.48      4.45      4.45      4.40      4.37      4.35
          ESI PZ-3    3.24      3.22      3.19      3.19      3.20      3.18      3.18
          ESI MW-3





                       7/18      7/24       8/1       8/16      8/24      9/4





          ESI 14W-4     9.28      9.18      9.16      9.13      9.12
          ESI MW-2      9.02      8.98      8.93      8.84      8.81
          ESI NW-7      7.68                7.60      7.56      7.49
          ESI MW-5      5.43      5.40      5.38      5.34      5.32
          ESI NW-12     5.54      5.52                5.43      5.42      5.38
          ESI MW-11     6.08      6.03                5.94      5.92      5.86
          ESI MW-10     6.48      6.44                6.28      6.26      6.20
          ESI NW-13     4.66      4.63      4.60      4.60      4.58      4.55
          ESI NW-9      5.05                4.92                4.99      4.86
          ESI NW-6      6.10      6.05      6.00                5.89      5.82
          ESI PZ-2      4.38      4.35      4.31      4.30      4.30      4.24
          ESI PZ-3      3.22      3.20      3.14                3.24      3.44
          ESI MW-3     14.29      14.26     14.25     14.21     14.20










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