No abstract

In the 9,950-square mile area of the Suwannee River basin in Florida and Georgia, 17 surface-water stations on 9 streams and several springs were sampled for selected water-quality properties and constituents from August 1968 through December 1977. Analyses from these samples indicate that:(1) the water quality of tributary wetlands controls the water quality of the upper Suwannee River headwaters, (2) ground water substantially affects the water quality of the Suwannee River basin streams below these headwaters, (3) the water quality of the Suwannee River is variable and not solely related to discharge, and (4) development in the Suwannee River basin has had observable effects on the quality of surface waters.

Water-quality data from 4h 1 surfacewater sites were compiled and analyzed to document the occurrence and distribution of pesticides in surface water of the Mid-Atlantic region as part of the Mid-Atlantic Integrated Assessment program of the U.S. Environmental Protection Agency. Those data collected hy the U.S. Geological Survey from October 1973 through March 1997 were used in the analyses. Data are available for a large part of the Mid-Atlantic region, but large spatial gaps in the data do exist. USCS data bases contained analyses of surface-water samples for 127 pesticide compounds, including 12 degradates, but only Ib of the compounds were commonly detected. Atrazine, metolachlor, sima/ine, prometon, alachlor, tebuthiuron, cyanazine, di

3 1 ContentsI iil CONTENTS (continued) Model sensitivity to selected hydraulic properties 3 65 Streambed leakance and stream loss 3 65 Hydraulic conductivity of bedrock valley east of Dover well field 3 66 Hydraulic conductivity of upland till 3 67 Summary 3 73 References cited 3 75 FIGURES 1-2. Maps showing locations of: 1. Northeast Glacial Aquifers RASA study area and localities selected for detailed study 32. Altitude of Rockaway River surface at four measurement sites, September 1983 through September 1985 � 49 33. Map showing land-surface altitude as simulated in Dover models 3 52 34-37. Maps showing Dover model grid and locations of : 34. Variable-Recharge zones � 54 35. Urbanized zones wherein water available for recharge was reduced � 55 36. Hydraulic conductivity zones, layer 1 � 57 37. Hydraulic conductivity zones, layer 2 � 58 38. Diagram showing locations of observation wells in relation to model grid and to a uniformly spaced interpolated grid within Dover well-field subregion. � 59 39. Graphs showing observed and adjusted water levels in individual wells on dates used for model calibration, and corresponding water levels simulated by models 1 and 6 3 63 40. Maps showing simulated heads in layer 1 of model 6 within the Dover well-field subregion, for six transient stress periods � 64 41-42. Maps showing head and flow direction at end of summer in Dover models: 41. In layer 2 of model 1 � 68 42. In layer 2 of model 2 � 69 43. Profiles along model row 14 showing effect of hydraulic conductivity of upland till on simulated end-of-summer heads under long-term average conditions 3 70 44-45. Maps showing simulated head and flow direction in Dover models at end of summer under long-term average conditions: 44. In layer 1 of model 1 3 71 In layer 1 of model 3 � 72Contents v TABLES 1.Ground-water withdrawals from Dover municipal well field, 1984-1985 3 10 2. Range and median concentration of major inorganic solutes and dissolved solids in Rockaway River, piezometers, and wells at Dover, N.J., July 1984 through August 1985 � 13 3. Carbon dioxide pressure and saturation indices for selected mineral phases in Rockaway River, piezometers, and wells at Dover, N.J. � 18 4. Chemical reactions that control solute chemistry near Dover, N.J. � 19 5. Computed and observed solute chemistry and isotope content at center of Dover well field (wellT5), September 1984 � 21 6. Regression equations developed to represent diurnal cycles of water-quality characteristics in Rockaway River and piezometer P2 at Dover, N.J., June 2-6, 1986 � 27 7. Alternative estimates of time required for diurnal dissolved-oxygen cycles to travel through streambed of Rockaway River at Dover, N.J., June 2-6, 1986 3 29 8. Seepage losses calculated from measurements of streamflow in the Rockaway River at Dover, N.J. . 3 33 9. Water-transmitting properties of the bed of the Rockaway River at Dover, N.J., as computed by four methods � 34 10. Maximum head differences across the streambed of the Rockaway River at Dover, N.J., measured July 6-7, 1988 � 35 ...

In this report, "sea level" refers to National Geodetic Vertical Datum of 1929 a geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level Datum of 1929. Chemical concentration, specific conductance, and water temperature are reported in metric units. Aqueous chemical concentration is given in milligrams per liter (mg/L) or in micrograms per liter Qig/L). Milligrams per liter is a unit expressing the concentration of chemical constituents in solution as well as weight (milligrams) of solute per unit volume (liter) of water. One thousand micrograms per liter is equivalent to one milligram per liter. For concentrations less than 7,000 mg/L, the numerical value is the same as for concentrations in parts per million. Hydrogen concentrations in samples are expressed in nanomoles per liter (nmol/L).