A data-collection site was instrumented on Jones Beach Island, a barrier island south of Long Island, N.Y., to study local freshwater/ saltwater relations in the shallow ground-water system. A geologic test boring revealed about 88 feet of well-sorted glacial outwash sand above about 15 feet of Gardiners Clay, which directly overlies silty sand of the Magothy Formation. Tidal effects on water levels in Great South Bay, the upper glacial aquifer, and the Magothy aquifer were observed and quantified with a tidal gage in the bay and analog water-level recorders in the wells.Chloride concentrations in the upper Magothy aquifer were higher than expected--about 270 mg/L (milligrams per liter), and those in the upper glacial aquifer were 17,000 to 19,000 mg/L, about the same as in Great South Bay. Estimates of pressure and freshwater equivalent heads indicate that, at the data-collection site, freshwater is discharging upward from the Magothy aquifer into the salty upper glacial aquifer, but dilution by this freshwater is undetectable. The reason for the elevated chloride concentration in the Magothy aquifer cannot be determined from available hydrogeologic information.

Traveltime of a soluble substance was determined for a 120-mile reach of the Delaware River from the confluence of the East Branch Delaware River and the West Branch Delaware River at Hancock, N.Y. to the Delaware Water Gap. Dye studies were conducted at the 85-95 percent and the 25-30 percent flow durations. Discharges ranged from 500-1,740 cubic feet per second during the 85-95 percent flow duration and 3,070-7,500 cubic feet per second for the 25-30 percent flow duration. The data were used to develop a set of time-concentration curves that would enable estimation of the traveltime of a spill at any point in the river within the study reach for 10 flow durations. The leading edge of a contaminant spill at Buckingham Access would take about 70 hours to reach the Delaware Water Gap when flows are at the 30-percent flow duration. The trailing edge (location of the dye cloud when concentrations would decrease to 10 percent of the peak concentration) would take about 50 hours after the arrival of the leading edge.

Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of several production wells in Suffolk County, N.Y., and has forced the Suffolk County Water Authority to adopt a costly well-reconditioning and replacement program. The specific-capacity declines are the result of the precipitation of iron oxyhydroxides and the growth of iron bacteria on the well screens and in the pore spaces of the surrounding formation. Mineralogic and chemical analyses indicate that the inorganic part of the encrusting material consists primarily of amorphous ferric hydroxide (Fe(OH)3 ); minor components of the material include goethite (FeOOH), hematite (Fe2 O 3 ), and quartz (SiO 2 ). The weight percent of ferric hydroxide in the material ranged from 32.3 to 98.6 percent and averaged 64.3 percent. Equilibrium modeling indicated that during pumping the well waters were supersaturated with respect to goethite, hematite, magnetite, and quartz and were under-saturated with respect to ferric hydroxide. Theoretical Eh values computed for the ferrous/ferric-iron redox couple and the oxygen/water redox couple averaged 390 millivolts and 810 millivolts, respectively, indicating that the waters were in a state of redox disequilibrium. The disequilibrium condition arises from the mixing of ground water with a low dissolved-oxygen concentration with oxygenated ground water during operation of the well. The low pH of the ground water contributes to the disequilibrium condition by slowing the rate of iron oxidation after the introduction of oxygen. Chemical and mineralogical data indicate that most of the encrusting material in the wells was deposited while the wells were shut down, probably in response to the use of treated water of higher pH to keep pump turbines wet while the wells were not in operation; the increased pH of water in the static water column increases the rate of ferrous-iron oxidation and causes the well water to become increasingly saturated with respect to ferric hydroxide. The median half-time of oxidation in samples of untreated ground water (pH 4-5) was 4.19 days, whereas the average half-time of oxidation in treated water (pH 7-8) was 11.9 minutes Equilibrium modeling indicated that treated waters generally were supersaturated with respect to ferric hydroxide, whereas untreated well waters were not. Field and laboratory data indicate that iron bacteria play an important role in the encrustation and biofouling process in Suffolk County. Filamentous iron bacteria were common in the affected wells. The most common species was Gallionella ferruginea, an effective biofouling agent that prefers water with low, but detectable, dissolved-oxygen concentrations and high dissolved-iron concentrations; this species was more common in biofilm samples from the Magothy aquifer than in those from the upper glacial aquifer. Iron bacteria also were found in sediment cores from several locations in the aquifer and in drilling water. Lignite could act as a carbon source for heterotrophic iron bacteria, which could accelerate the formation of iron-bacteria biofilms in wells screened in some parts of the Magothy aquifer. Iron-bacteria biofilms alter the chemistry of well water by removing iron, manganese, and sulfate from solution and by increasing the pH. Sulfur-reducing bacteria and iron-sulfide mineral phases were observed in some samples of encrusting material, indicating that these bacteria could contribute to well-screen encrustation in some geochemical environments.

Three issues are currently being addressed with respect to the Lake Ontario ecosystem: eutrophication, contamination by toxic substances and fisheries management. This report reviews our present knowledge and understanding of Lake Ontario within the context of the first two issues. Although the report focuses on intensive studies carried out during 1981-82, it relies heavily on work from 1967 to 1985. I n preparing this report, it became obvious that many fundamental questions regarding the functioning of the Lake Ontario ecosystem remain unanswered. For example, although the total phosphorus load has been reduced to a level approaching the target load, those factors that control and/or limit algal biomass and productivity (e.g. is the lake phosphorus limited) remain poorly understood. Salmonid stocking of the lake continues in unprecedented numbers, yet our knowledge of foodweb interactions is very limited. Nitrate levels continue to rise significantly in the lake, but little effort has been made to identify the causes and consequences of this increase; the Water Quality Board has raised this issue in their 1985 and 1987 reports to the International Joint Commission.

A plume of contaminated ground water has been delineated within an 11.4-square-mile area in east-central Nassau County, where residential neighborhoods surround an area zoned for industrial use. The industrial zone contains several firms that, in the past, have discharged effluent containing volatile organic compounds into the upper glacial aquifer through onsite recharge basins. The upper glacial aquifer is in direct hydraulic connection with the underlying Magothy aquifer; the first continuous formation that impedes downward movement of ground water is the Raritan confining unit, which is more than 500 feet below sea level. The chemicals in ground water·and their distribution were identified through analysis of water samples collected from 56 monitoring wells and 11 industrial wells in the spring and fall of 1986 and 1987. Trichloroethylene and tetrachloroethylene were found near the water table at concentrations greater than 1,000 micrograms per liter and were detected more than 5,000 feet downgradient of the industrial zone. The distribution of several other volatile organic compounds indicates more than one contaminant source in the industrial area. The plume of contaminated ground water in 1987 was 12,000 feet long, 5,700 feet wide, and more than 500 feet thick. In 1987, water was pumped from 14 industrial wells, completed in the Magothy aquifer, at an average rate of 8.05 million gallons per day, mainly for cooling purposes. The water was returned chemically unaltered to recharge basins from which it could percolate to the water table. Water-table mounding beneath basins and drawdowns near the pumped wells greatly increase the vertical component of ground-water flow beneath the industrial zone, which has increased the rate of advective movement of contaminated ground water downward toward the screened zones of pumped wells, which are 370 to 560 feet deep in the Magothy aquifer. The concentration of tetrachloroethylene decreases much more rapidly than that of trichloroethylene downgradient of the industrial zone, which indicates that sorption and (or) biodegradation may be occurring. The major effect of industrial activity on inorganic constituents is to decrease the concentration of constituents near the water table in the vicinity of the recharge basins by the addition of water from the Magothy aquifer, where the concentration of inorganic constituents is lower.

Heavy rain during January 18-19, 1996, combined with unseasonably warm temperatures that caused rapid snowmelt, resulted in widespread flooding throughout New York State. Damages to highways, bridges, and private property exceeded $100 million. The storm and flooding claimed 10 lives, stranded hundreds of people, destroyed or damaged thousands of homes and businesses, and closed hundreds of roads. Forty-one counties in New York were declared federal disaster areas. The most severely affected region was within and surrounding the Catskill Mountains. Damages and losses within Delaware County alone exceeded $20 million.More than 4.5 inches of rain fell on at least 45 inches of melting snow in the Catskill Mountain region during January 18-19 and caused major flooding in the area. The most destructive flooding was along Schoharie Creek and the East and West Branches of the Delaware River. Record peak discharges occurred at 57 U.S. Geological Survey streamflow-gaging stations throughout New York. Maximum discharges at 15 sites, mostly within the Schoharie Creek and Delaware River basins, had recurrence intervals equal to or greater than 100 years. The storage of significant amounts of floodwater in several reservoirs sharply reduced peak discharges downstream. This report presents a summary of peak stages and discharges, precipitation maps, floodflow hydrographs, inflow-outflow hydrographs for several reservoirs, and flood profiles along 83 miles of Schoharie Creek from its headwaters in the Catskill Mountains to its mouth at the Mohawk River.

Cultivated mucklands in western New York State were investigated as a nonpoint source of phosphorus to Lake Ontario. The 70,500-ha Oak Orchard Creek watershed, which drains to Lake Ontario, was selected for the study area. It is located in Genesee and Orleans Counties, New York, and contains 3250 ha of heavily fertilized muck cropland on which predominantly vegetable crops are grown. The creek was monitored at several sites from May 1984 through April 1985 to determine the role of the mucklands in annual phosphorus loading to the lake. At an upstream site which drained approximately 10,200 ha, including the majority of the muck cropland, the creek load was 18,000 kg of total phosphorus with 75 percent of it as dissolved reactive phosphorus. Two-thirds of the annual load was delivered in the 3-month, high-flow period of February through April. Runoff during the late winter-early spring period appears to be the most important hydrologic factor in governing annual phosphorus loading from the mucklands, greater than either total precipitation or total runoff for the year. The pesticide DDT and its metabolites, DDE and DDD, were detected in muck soils and in creek suspended and bed sediments at this site. Although the annual loading rate of these compounds was thought to be relatively small, based on limited sampling, accumulation in the freshwater wetlands downstream which contain both a federal and a state wildlife refuge, could pose a hazard to sensitive species and warrants possible further investigation. A number of impoundments on the creek downstream of the mucklands, including the managed freshwater wetlands and two hydroelectric facilities, did not appear to significantly affect transport of phosphorus through the system during high-flow, late-winter months. In the largest impoundment, Waterport Pond, which is located 10 km from the creek mouth, internal loading of phosphorus from bottom sediments occurred during periods of hyrolirnnetic anoxia. Uptake and removal of bioavailable phosphorus by algae in Waterport Pond, rather than dilution by incremental flaw 1 was thought to account for a spatial phosphorus concentration gradient evident in summer months. The overall effect of Waterport Pond on annual phosphorus loading to Lake Ontario appeared to be removal of about 25 percent of the dissolved reactive form. Total phosphorus loading to Lake Ontario from Waterport Pond was 37. tonnes for the study year with 54 percent in the dissolved reactive form. Half of the load was delivered during the high-flaw months of March through May. A phosphorus load mass balance for Waterport Pond indicates that the greatest portion derives from the upper watershed containing the cultivated mucklands. Other smaller sources are the Village of Medina wastewater treatment plant and seasonal diversions of supplemental flow from the Erie Barge Canal. Control of phosphorus losses from the mucklands would appear to offer the most significant and cost-effective opportunities for loading reductions from this watershed.

During the spring, summer and autumn of 1985, the structure of the phytoplankton and zooplankton communities in the offshore waters of Lake Michigan, Lake Huron and Lake Erie was monitored. In Lake Michigan, the presence of an oligotrophic rotifer association and the oligotrophic crustacean indicator species Diaptomus sicilis and Limnaealanus macrurus, the predominance of mesotrophic diatom species, and the abundance and biomass of plankton between that of Lake Huron and Lake Erie suggest that the offshore waters are currently in the oligotrophic-mesotrophic range. In Lake Huron, the presence of an oligotrophic rotifer assemblage, the domination of the calanoid copepods, the abundance of the oligotrophic Diaptomus sicilis, and relatively low zooplankton abundance suggest that the offshore waters continue to be oligotrophic. In Lake Erie, phytoplankton and zooplankton species composition and biomass suggest a more productive status than Lake Michigan and Lake Huron. Data support the classification of the Western Basin as meso-eutrophic, the Central Basin as mesotrophic and the Eastern Basin as oligo-mesotrophic. Significant changes in the composition of the zooplankton community with the appearance of the large cladoceran Daphnia pulicaria in Lake Erie are attributed to a change in planktivory. The planktivorous emerald and spottail shiners have dramatically declined in abundance, possibly due to a resurgence of the walleye and the salmonine stocking programs.

This government document is the proceedings of a national conference held in Kansas City, Missouri from May 19-22, 1985. The goals of the conference were fourfold: (1) focus on drawing information from everybody involved with the problem; (2) find out how people throughout the country, at the local level, perceive the nonpoint source problem and how they believe it should be handled; (3) make the information flow from the grass roots upward-the Federal role was to listen and learn and exchange information, not to dominate; and (4) make it practical. Four basic themes evolved as the conference developed: (1) Find practical, affordable solutions not imposed by Federal authority but worked out at the local level. (2) Put to work existing knowledge. (3) Address nonpoint source pollution at the local level. (4) Cooperation is the key. The resulting papers are diverse in length, format, and tone and offer different perspectives on the problem of nonpoint source pollution of our Nation's water.

The Rochester Embayment designation refers to a portion of Lake Ontario and a portion of the Genesee River near Rochester, New York. The Remedial Action Plan (RAP) will identify water quality problems and specific actions that need to be taken by various parties to address the problems. The Remedial Action Plan effort has been undertaken due to an international agreement to improve the water quality of the Great Lakes water system. The International Agreement, known as the Great Lakes Water Quality Agreement, is described in more detail in other sections of this chapter. The preparation of the RAP is being coordinated by the Monroe County Department of Planning and Development through a contract with the New York State Department of Environmental Conservation (NYSDEC).