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Source-linked reports with geographic coverage including Wisconsin.

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Evaluation of nonpoint-source contamination, Wisconsin; selected streamwater-quality data, land-use and best-management practices inventory, and quality assurance and quality control, water year 1993

The objective of the watershed-management evaluation monitoring program in Wisconsin is to evaluate the effectiveness of the best-management practices (BMPs) for rural streams, urban streams, and urban storm sewers. This report is an annual summary of the data collected for the program and a report of the results from several different special studies conducted within this program. Suspended sediment and total phosphorus storm-load data are summarized for eight rural sites and suspended sediment, total phosphorus, total recoverable lead, total recoverable copper, total recoverable zinc, and total recoverable cadmium storm-load data are summarized for four urban sites. Dissolved-oxygen data is summarized and compared with Wisconsin's waterquality standards for summer 1993 for seven rural sites. The dissolved-oxygen concentrations declined to levels below these standards at least one time at all seven sites during summer 1993. Total-recoverable hardness concentrations were compared with dissolved-hardness concentrations at two urban streams and two urban storm sewers. Least-squared linear regressions resulted in stronger relations for low-flow conditions than for high-flow conditions, indicating that most hardness during low flow is dissolved hardness. Pesticide data are summarized for four urban sites and six rural sites. Herbicides were detected at urban and rural sites; whereas insecticides were detected only at urban sites. A land-use and best-management-practice inventory is ongoing for each evaluation monitoring project to track the different sources of nonpoint pollution in each watershed and to document implementation of best-management programs that may cause changes in water quality of streams. Updated information is gathered each year, mapped, and stored in a geographic-information-system data base. The quality-assurance/quality-control plan for the urban watershed-management evaluation program consisted of a series of blank samples. These blank samples were used to identify and isolate contamination by inorganic and organic components throughout the collection and processing of urban streamwater samples. A dissolved trace-metal contamination problem was identified and resolved by using different laboratory- supplied sample bottles. A special study was done to determine the effect of holding time on fecal coliform colony counts. A linear regression indicated that the mean decrease in colony counts over 72 hours was 8.2 percent per day. Results after 24 hours showed that colony counts increased in some samples and decreased in others.

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Water-quality and lake-stage data for Wisconsin lakes, water year 1994

The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many yes rs, provide a data base for developing an improved understanding of the water quality of lakes\ To make these data available to interested parties outside the USGS, the data are published annually in this report series. The location of surface water-quality and lake-stage stations in Wisconsin for water year 1994 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends and which includes 9 of the 12 months. Thus the period October 1, 1993 through September 30, 1994, is called "water year 1994." The purpose of this report is to provide information about the physical, che-nical, and biological characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected includes measurements of lake stage and in-lake water quality. Graphs of Secchi depths, and total-phosphorus and chlorophyll-a concentrations versus time are included for lakes with two or more years of data. Descriptive information for each lake includes location of the lake, drainage area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in two other volunres: "Water Resources Data-Wisconsin, 1994, St. Lawrence River Basin" (Volume 1) and "Water Resources Data-Wisconsin, 1994, Upper Mississippi River Basin" (Volume 2).

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Evaluation of nonpoint-source contamination, Wisconsin: Land-use and Best-Management-Practices inventory, selected streamwater-quality data, urban-watershed quality assurance and quality control, constituent loads in rural streams, and snowmelt-runoff analysis, water year 1994

The objective of the watershed-management evaluation monitoring program in Wisconsin is to evaluate the effectiveness of best-management practices (BMP) for controlling nonpoint-source contamination in rural and urban watersheds. This report is an annual summary of the data collected for the program by the U.S Geological Survey and a report of the results of several different detailed analyses of the data. A land-use and BMP inventory is ongoing for 12 evaluation monitoring projects to track the sources of nonpoint-source pollution in each watershed and to document implementation of BMP's that may cause changes in the water quality of streams. Updated information is gathered each year, mapped, and stored in a geographic-information-system data base. Summaries of data collected during water years 1989-94 are presented. A water year is the period beginning October 1 and ending September 30; the water year is designated by the calendar year in which it ends. Suspended-sediment and total-phosphorus data (storm loads and annual loads) are summarized for eight rural sites. For all sites, the annual suspended-sediment or suspended-solids load for water year 1993 exceeded the average for the period of data collection; the minimum annual loads were transported in water year 1991 or 1992. Continuous dissolved-oxygen data were collected at seven rural sites during water year 1994. Data for water years 1990-93 are summarized and plotted in terms of percentage of time that a particular concentration is equaled or exceeded. Dissolved-oxygen concentrations in four streams were less than 9 mg/L at least 50 percent of the time, a condition that fails to meet suggested criterion for coldwater streams. The dissolved-oxygen probability curve for one of the coldwater streams is markedly different than the curves for the other streams, perhaps because of differences in aquatic biomass. Blank quality-assurance samples were collected at two of the urban evaluation monitoring sites to isolate contamination in the sample bottle, the automatic sampler and splitter, and the filtration system. Significant contamination caused excessive concentrations of dissolved chloride, alkalinity, and biochemical oxygen demand. The level of contamination may be large enough to affect data for water samples in which these analytes are present at low concentration. Further investigation is being done to determine the source of contamination and take measures to minimize its effect on the sampling. A preliminary regression analysis was done for the rural sites using data collected during water years 1989-93. Loads of suspended solids and total phosphorus in stormflow were regressed against various precipitation-related measures. The results indicate that, for most sites, changes in constituent load on the order of 40 to 50 percent could be detected with a statistical test. For two sites, the change would have to be 60 to 70 percent to be detected. A detailed comparison of snowmelt runoff and rainfall stormflow in urban and rural areas was done using data collected during water years 1985-93. For the rural sites where statistically significant differences were found between constituent loads in snowmelt and storm runoff, the loads of suspended solids and total phosphorus in snowmelt runoff were greater than those in storm runoff. For the urban sites where statistically significant differences were found between snowmelt and storm runoff, the loads of suspended solids and total phosphorus in storm runoff were greater than those in snowmelt runoff. The importance of including snowmelt runoff in designing and analyzing the effects of BMP's on streamwater quality, particularly in rural areas, is emphasized by these results.

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Water-resources investigations in Wisconsin, 1995

The statewide average precipitation of 30.66 inches for the 1994 water year was 96 percent of the normal annual precipitation of 31.79 inches for water years 1961-90. Average precipitation values ranged from 81 percent of normal in southeastern Wisconsin to 103 percent of normal in west-central Wisconsin (Pamela Naber Knox, UW-Extension, Geological and Natural History Survey, written commun., 1994). Runoff was variable for rivers throughout the State ranging from 60 percent in southeast Wisconsin to 142 percent in west-central Wisconsin. Runoff was lowest (60 percent of the average annual runoff from 1972-94) for the Pike River near Racine. Runoff was highest (142 percent of the average annual runoff from 1915-19, 1935-94) for the Trempealeau River at Dodge. Departure of runoff in the 1994 water year as a percent of long-term average runoff in the State are shown in Figure 4.

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Ground-water flow and quality in Wisconsin's shallow aquifer system

The areal concentration distribution of commonmineral constituents and properties of ground water in Wisconsin's shallow aquifer system are described in this report. Maps depicting the water quality and the altitude of the water table are included. The shallow aquifer system in Wisconsin, composed of unconsolidated sand and gravel and shallow bedrock, is the source of most potable ground-water supplies in the State. Most ground water in the shallow aquifer system moves in local flow systems, but it interacts with regional flow systems in some areas. In terms of chemical quality, the water is suitable for potable supply and most other uses, but objectionable hardness in large areas and concen- trations of iron and manganese that exceed State drinking-water standards cause aesthetic problems that may require treatment of the water for some uses. Concentrations of major dissolved constitu- ents (calcium, magnesium, and bicarbonate), hard- ness, alkalinity, and dissolved solids are highest where the bedrock component of the aquifer is dolo- mite and lowest where the shallow aquifer is almost entirely sand and gravel. Concentrations of other minor constituents (sodium, potassium, sulfate, chloride, and fluoride) are less closely related to common minerals that compose the aquifer system. Sulfate and fluoride concentrations exceed State drinking-water standards locally. Extreme variability in concentrations of iron and manganese are common locally. Iron and manganese concentra- tions exceed State drinking-water standards in water from one-third and one-quarter of the wells, respectively. Likely causes of nitrate-nitrogen con- centrations that exceed State drinking-water stan- dards include local contamination from plant fertilizers, animal wastes, waste water disposed of on land, and septic systems. Water quality in the shallow aquifer system has been affected by saline water from underlying aquifers, primarily along the eastern and western boundaries of the State where the thickness of Paleozoic rocks is greatest.

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Hydrogeology of southwestern Sheboygan County, Wisconsin, in the vicinity of the Kettle Moraine Springs fish hatchery

This report describes the hydrogeology of the dolomite aquifer of Silurian age and its relation to springs in a study area in southwestern Sheboygan County, Wisconsin. The study was conducted at the Kettle Moraine Springs fish hatchery in cooperation with the Wisconsin Department of Natural Resources. The dolomite aquifer is overlain by more than 60 feet of glacial deposits. Fine-grained glacial deposits confine the dolomite aquifer in the lowland at the hatchery. Thicker, coarse-grained glacial deposits overlie the dolomite aquifer on the hills surrounding the hatchery. The coarse-grained deposits are in good hydraulic connection with the aquifer. The transmissivity and storage coefficient of the dolomite aquifer are 1,220 feet squared per day and 0.0007, respectively. Pumping from the aquifer results in drawdown in wells open to the aquifer and the effects of this pumping will decrease the greater the distance between wells. The amount of drawdown caused by pumping was estimated by means of distance-drawdown curves. Five springs and two wells open to the dolomite aquifer supply water to the hatchery. Groundwater withdrawals from fish hatchery wells affect the water level in an observation well near the springs and probably decrease the flow from the springs to the hatchery. Additional pumping from the aquifer probably will further decrease flow from the springs.

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Radon-222 concentrations in ground water and soil gas on Indian reservations in Wisconsin

The weighted average radon-222 concentration of indoor air in homes located on Wisconsin Indian Reservations is 5.8 picocuries per liter, which exceeds the U.S. Environmental Protection Agency action limit of 4 picocuries per liter. Ground water is the principle source of drinking water on Wisconsin Indian Reservations and generally accounts for about 5 percent of the total indoor air radon-222 concentrations found in homes. To determine the distribution of radon-222, ground water from 29 private and community Wisconsin Indian Reservation wells and soil gas at a depth of about 3 feet below land surface adjacent to the wells were sampled. Sites with wells were distributed among the 11 Wisconsin Indian Reservations so that each Reservation contained at least 2 sites. The remaining seven sites were divided among the Reservation by acreage held by each tribe. Ground-water samples were collected using a syringe technique after the wells had been purged sufficiently to reach chemical stability. Samples were then sent by overnight mail to the U.S. Geological Survey, National Water Quality Lab for analysis by liquid scintillation counting. Soil gas was collected in Lucas cells, using a small-diameter soil probe and peristaltic pump. The cells were then analyzed by Lucas cell alpha scintillation counting with a portable radon detector. The highest radon-222 concentrations in ground water and soil gas are from sites with wells finished in the crystalline bedrock aquifer. Radon-222 concentrations in 29 ground-water samples collected from the sand and gravel and sedimentary and crystalline bedrock aquifers range from 260 to 22,000 picocuries per liter with a median concentration of 560 picocuries per liter. Only 2 of the 29 ground-water samples have radon-222 concentrations less than the U.S. Environmental Protection Agency proposed standard of 300 picocuries per liter. The highest radon-222 concentrations were found in ground water from wells in Shawano, Menominee, Forest, and Marathon counties. Radon-222 concentrations in soil gas range from 130 to 7,810 picocuries per liter with a median concentration of 560 picocuries per liter. For sites with wells finished in the sand and gravel aquifer, the coefficient of determination (R2) of the regression of concentration of radon-222 in ground water as a function of well depth is 0.003 and the significance level is 0.32, which indicates that there is not a statistically significant relation between radon-222 concentrations in ground water and well depth. The coefficient of determination of the regression of radon-222 in ground water and soil gas is 0.19 and the root mean square error of the regression line is 271 picocuries per liter. Even though the significance level (0.036) indicates a statistical relation, the root mean square error of the regression is so large that the regression equation would not give reliable predictions. Because of an inadequate number of samples, similar statistical analyses could not be performed for sites with wells finished in the crystalline and sedimentary bedrock aquifers.

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Water resources of the Bad River Indian Reservation, northern Wisconsin

Water-resources data were collected in the Bad River Indian Reservation of northern Wisconsin from 1983 through 1987. Some data are interpreted to describe ground-water flow, groundwater quality, streamflow, and surface-water quality. Data also are presented in tables and appendixes for baseline reference. Precambrian sandstone and basalt underlie varying thicknesses of sandy till, outwash sand and gravel, and clay deposited in glacial meltwater lakes. The thickness of glacial deposits generally ranges from 100 to 300 ft but reaches a known thickness of almost 1,000 ft on the east-central edge of the Reservation. Sand and gravel deposits are generally buried beneath 50 to 150 ft of glacial lake clays and silts throughout most of the Reservation. These buried sand and gravel deposits lie directly on Precambrian sandstone of unknown thickness in the northern half of the Reservation. The sand and gravel deposits and the sandstone form a single aquifer system confined by the overlying clay deposits. In and near the village of Odanah, numerous wells finished in either the sand and gravel or in the sandstone flow above land surface. Estimates of the horizontal hydraulic conductivity of the sand and gravel based on 30 specific- capacity tests range from about 2 to 700 ft per day with a median value of about 80 ft per day. Horizontal hydraulic conductivity estimates for the sandstone range from about 1 to 360 ft per day with a median of about 2 ft per day. These estimates are based on 42 specific-capacity tests of wells open only to the upper 20 to 60 ft of sandstone. The horizontal hydraulic conductivity of the sandstone appears to decrease with depth; highest estimates were determined for wells open only to the upper 20 ft of sandstone. Ground water in the confined aquifer system is a calcium magnesium bicarbonate type with relatively low total dissolved solids concentrations. The median total dissolved solids concentration of water from 17 sand and gravel wells is about 150 milligrams per liter and the median for water from 21 sandstone wells is about 244 milligrams per liter. High concentrations of iron and manganese were found in water from 12 of 36 sampled wells. Total recoverable concentrations of iron exceeded 500 micrograms per liter in 5 wells and concentrations of manganese exceeded 50 micrograms per liter in 7 wells. Streamflow has been continuously measured at a streamflow-gaging station in the Bad River near Odanah for much of the time since 1914. This station monitors drainage from a basin with an area of 597 square miles and the average daily discharge of the Bad River at this gaging station is 622 cubic feet per second. The peak instantaneous flow at the station was 27,700 cubic feet per second on April 24, 1960 and the minimum instantaneous flow was 34 cubic feet per second on November 8,1976. Analysis of water samples collected at 12 sites at 10 small streams during base-flow conditions indicate that the concentrations of common chemical constituents are similar to but lower than those found in ground water. The median concentration of total dissolved solids was about 110 milligrams per liter as compared to about 155 milligrams per liter in ground-water samples from wells finished in sand and gravel.

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Malignant lymphoma in black bullhead from Allouez Bay, Superior, Wisconsin, USA

Leukemic malignant lymphoma was diagnosed in a black bullhead collected from Allouez Bay, in an industrialized Lake Superior estuary near Superior, Wisconsin, USA. No gross signs of thymic involvement were observed and it is believed this tumor originated in the hematopoetic tissue of the kidney. Neoplastic cells infiltrated excretory kidney, spleen, liver and gill tissue. This finding is of interest since occurrence of lymphoma has not previously been reported in this fish species. In addition, the general condition of black bullheads collected at this site was examined using a necropsy-based health assessment. Most parameters were within normal ranges. However, blood parameters and the amount of visceral fat suggested these fish may not be in optimal condition. Further work is needed to document the prevalence and cause of the neoplasm in this black bullhead population.

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Shoreline and coastal wetland variability along the west shore of Green Bay, Marinette and Oconto counties, Wisconsin

Coastal wetland ecosystems along the Great Lakes shorelines are extremely valuable natural resources. They provide numerous environmental and recreational benefits, and they serve as critical habitats for fish and wildlife populations. In general terms, wetlands can be defined as lands transitional between terrestrial and aquatic systems; they are characterized by periodic submergence or a water table at or near the surface and a predominance of hydric soils and hydrophytes. Changes in shoreline positions over time result in concomitant changes in the amount of adjacent coastal wetlands, frequently resulting in a permanent loss of these valuable resources. In the Great Lakes region, the main natural cause of shoreline changes are lake-level fluctuations that result from two interactive factors. One factor is the glacio-isostatic rebound of the lake basins, which has been occurring since the end of the late Wisconsin glaciation to the present. This crustal rebounding has slowly uplifted previous lake outlets, warped and tilted lake basins, and changed lake levels and shoreline positions. On the basis of historic lake-level gauge records, measured modern differential vertical uplift rates range from 0.26 ft/century in the southern part of the Great Lakes drainage basin to 1.74 ft/century in the northern part of the basin (Larsen, 1989). The second factor contributing to lake-level fluctuations is climate variability, which controls the amount of regional precipitation and evaporation, storm frequency, runoff, and resulting lake levels. Climate variability can occur over a wide spectrum of time scales; it can range from seasonal variations, to long-term trends of a few years or decades in duration, to trends lasting hundred of thousands of years. Climatic variations, in conjunction with glacio-isostatic rebound, have resulted in substantial temporal variability of the Great Lakes shorelines and associated wetland tracts during post-glacial times.

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Temporal variability of shoreline positions and coastal wetlands along lower Green Bay, Oconto and Brown counties, Wisconsin

The positions of shorelines and the areal extent of adjacent coastal wetland tracts in the Great Lakes region have exhibited substantial temporal variability during both prehistoric and historical times. Shoreline migration has resulted in environmental problems such as flooding and the coastal erosion of lakefront property, as well as the destruction of coastal wetland resources. In the Great Lakes region, the main natural cause for changes in shoreline position and adjacent wetland area is lake-level fluctuations, which results from two interactive factors. One factor is the glacio-isostatic rebound of the lake basins that has occurred from the end of the late Wisconsin glaciation to the present. This crustal rebounding has resulted in the slow uplifting of previous lake outlets and warping of lake basins, contributing to changing lake levels and shoreline migration. Historic lake-level gauge records indicate modern differential vertical uplift rates that range from 0.26 ft/century in the southern part of the Great Lakes drainage basin to 1.74 ft/century in the northern part of the basin (Larsen, 1989). The second factor contributing to lake-level fluctuations is climate variability, which causes variations in the amount of regional precipitation and evaporation, storm frequency, runoff, and resulting lake levels. Climate variability can occur over a wide spectrum of time scales, from seasonal variations, to longer-term trends of a few years or decades in duration, to trends lasting hundreds of thousands of years. A combination of both climatic variations and glacio-isostatic rebound has resulting in substantial temporal variability of the Great Lakes shorelines and associated coastal wetland tracts during post-glacial times.

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Water-resources investigations in Wisconsin

The statewide average precipitation of 38.79 inches for the 1993 water year was 122 percent of the normal annual precipitation of 31.77 inches for water years 1961-90. Average precipitation values ranged from 103 percent of normal in northwestern Wisconsin to 150 percent of normal in southwestern Wisconsin (Pamela Naber Knox, UW-Extension, Geological and Natural History Survey, written commun., 1993). Runoff was variable for rivers throughout the State ranging from 99 percent in northcentral Wisconsin to 278 percent in southwestern Wisconsin. Departure of runoff in the 1993 water year from long-term average runoff is shown in figure 4, along with long-term average runoff for the period 1951-80. Runoff was lowest (99 percent of the average annual runoff from 1936-93) for the Wisconsin River at Rainbow Lake near Lake Tomahawk. Runoff was highest (278 percent of the average annual runoff from 1939-93) for the Pecatonica River at Darlington. The average annual runoff for the 1993 water year was the maximum for the period of record at 33 long-term stations (more than 10 years of record) in the southern half of Wisconsin. A comparison of the annual discharge for the individual water years (1916-93) at the Oconto River near Gillett, Jump River at Sheldon, and Sugar River near Brodhead is shown figure 5, The comparisons of monthly and annual discharges for the 1993 water year to discharge for a 78-year base period at the same three gaging stations are shown in figure 6. Spring runoff from snowmelt and major storms, in the period March through September 1993, caused floods with discharges that equalled or exceeded those with a recurrence interval of 10 years (Krug and others, 1991) at a number of crest-stage gage and gaging stations.

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Water resources of the Menominee Indian Reservation of Wisconsin

Water resources of the Menominee Indian Reservation, Wisconsin, were investigated during the period October 1981 through September 1987. The report presents baseline data and some interpretation of ground- and surface-water hydrology and quality of the Reservation. The area stratigraphy consists of basal Precambrian crystalline bedrock and overlying till and sand and gravel deposits. In the Reservation, the glacial deposits range in thickness from zero to 180 feet. The bedrock aquifer is composed of fractured and weathered Precambrian bedrock within about 20 feet of the upper bedrock surface. The sand and gravel aquifer is composed of saturated, permeable sand and gravel that occurs as layers, lenses, terrace deposits, and valley fillings. The glacial material has a saturated thickness ranging from approximately 150 feet to zero feet in areas where the Precambrian bedrock crops out. Water-table conditions commonly occur in both aquifers. Horizontal hydraulic conductivity of the sand and gravel and bedrock aquifers is estimated to be 5 and 0.3 feet per day, respectively. The Wolf River and its tributaries drain the Reservation except for the eastern quarter, which is drained by the South Branch of the Oconto River. The average discharge of the Wolf River, monitored continuously during 1907-85 at Keshena Falls near Keshena, was 762 ft 3/s (cubic feet per second). Maximum instantaneous discharge was 5,200 ft3/s recorded on March 15, 1973, and the minimum was 91 ft3/s recorded on December 22,1939. Low flow and flood-frequency characteristics for the Wolf River were estimated using mean-daily discharge for the period of record at Keshena Falls. Ground water from the sand and gravel and bedrock aquifers is a calcium magnesium bicarbonate type. The composition of waters from the two aquifers is similar because water recharging the bedrock aquifer is from the overlying sand and gravel aquifer. Iron or manganese concentrations exceeding secondary maximum contaminant levels were found in water samples from approximately one-quarter to one-half of the wells sampled. Approximately three-quarters of the groundwater sampled during the study is moderately hard to very hard, with a median hardness equal to 171 mg/L (milligrams per liter) (as calcium carbonate)for the sand and gravel aquifer and 165mg/L (as calcium carbonate) for the bedrock aquifer. Alkalinity of the ground water ranged from26 to 211 mg/L, with a median value of 182 mg/L(as calcium carbonate) for the sand and gravel aquifer and ranged from 72 to 250 mg/L, with a median value of 170 mg/L (as calcium carbonate)for the bedrock aquifer. Water samples collected from Reservation streams and lakes were similar to ground water (calcium magnesium bicarbonate type), reflecting the strong surface-water/ground-water interaction in the study area. The chemical composition of water from lakes having inlets or outlets indicate that they are not influenced by precipitation as much as lakes that do not have inlets or outlets.

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Hydrology and water quality of Whitewater and Rice lakes in southeastern Wisconsin, 1990-91

The hydrology and water quality of Whitewater and Rice Lakes was studied by the U.S. Geological Survey during November 15, 1990November 14, 1991, in cooperation with the Whitewater-Rice Lakes Management District, Walworth County, Wis. Whitewater and Rice Lakes are small, shallow lakes; surface areas are 697 and 162 acres and mean depths are 8.4 feet and 5.8 feet, respectively. Although both lakes have surface outlets, water levels were below the dam crests during the study, and no water left the lake through the outlets. The drainage basin of Whitewater Lake is 10.9 square miles and that of Rice Lake is 11.8 square miles; but, because of large amounts of depressional areas, only 1.4 square miles and 0.2 square mile, respectively, contribute surface runoff to the lakes. Whitewater Lake is an artificial lake created in 1947 by the damming of three smaller lakes. Rice Lake is an artificial lake created in 1954 by the damming of Whitewater Creek, which drains Whitewater Lake. Maintaining the lake levels at the elevations of their dam crests has been difficult since the lakes were created. For most years, water levels were below the lakes' dam crests. Ground water, precipitation, and evaporation are important components in the hydrologic budgets of the lakes. For Whitewater Lake, ground water was the dominant source of water, accounting for 57 percent of the inflow budget; precipitation accounted for 26 percent. Ground water also dominated the outflow, accounting for 81 percent of the outflow budget. The remaining 19 percent of the outflow budget was evaporation. For Rice Lake, precipitation was the dominant source of water, accounting for 88 percent of the inflow budget; ground water accounted for 8 percent. Evaporation dominated the outflow budget, at 70 percent, whereas ground water accounted for 30 percent. The external phosphorus budget for Whitewater Lake showed that shoreline drainage was the largest source of phosphorus to the lake42 percent of the total input of 558 pounds. Other sources of phosphorus were septic systems, 19 percent of the total; precipitation, 18 percent; a spring inlet at base flow, 13 percent; and ground water, 8 percent. The external phosphorus budget for Rice Lake showed that shoreline drainage also was the largest source of phosphorus to the lake-59 percent of the total input of 63 pounds; other sources were precipitation, 38 percent of the total; and ground water, 3 percent. Application of Vollenweider's phosphorus loading model fairly accurately predicted the lakes' spring turnover phosphorus concentrations and suggested that the external loading of phosphorus would result in mesotrophic to eutrophic conditions for Whitewater Lake and mesotrophic conditions for Rice Lake. Dillon and Rigler's model further suggested additional phosphorus from internal recycling was required to result in the high chlorophyll-a concentrations experienced in both systems during summer. Internal recycling of phosphorus in addition to external loading seems to also cause waterquality problems in both lakes. The amount of phosphorus recycled from the lake sediments was estimated from a mass-balance approach for April 1-November 14, 1991. For Whitewater Lake, the internal load of 582 pounds was slightly greater than the annual external load of 558 pounds. For Rice Lake, the internal load of 295 pounds far exceeded the annual external load of 63 pounds.

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Uptake of planar polychlorinated biphenyls and 2,3,7,8-substituted polychlorinated dibenzofurans and dibenzo- p -dioxins by birds nesting in the lower Fox River and Green Bay, Wisconsin, USA

The uptake of persistent polychlorinated hydrocarbons (PCHs) by four avian species was investigated at upper trophic levels of two aquatic food chains of the lower Fox River and Green Bay, Wisconsin. Accumulation of total and specific planar polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxin (PCDDs), and H411E rat hepatoma cell bioassay-derived 2,37,8-tetrachlorodibenzop-dioxin equivalents (TCDD-EQ) was evaluated in Forster's tern ( Sterna forsteri ) and common tern ( Sterna hirundo ) chicks, and in tree swallow ( Tachycineta bicolor ) and red-winged blackbird ( Agelaius phoeniceus ) nestlings from colonies nesting in several locations within the watershed. Concentrations of the PCHs were greatest in eggs and chicks of the two tern species, less in the tree swallows and least in the red-winged blackbirds. Young of all four species accumulated total PCBs, PCB congeners 77, 105, 126, and 169, and TCDD-EQ. The young birds also accumulated small concentrations of several 2,3,7,8-sbustituted PCDF and PCDD congeners. Uptake rates for certain of the PCHs for the Forster's tern chicks were: 15 μg/day for total PCBs, 70, 200, 6.5, and 0.14 ng/day for PCB congeners 77, 105, 126, and 169, respectively, and 270 μg/day for TCDD-EQ. Principal components analysis revealed that the patterns of PCH concentrations in the samples were influenced by species of bird, their age (or length of exposure) and nesting location. Collectively, our findings demonstrate that exposure of avian species to contaminants derived from aquatic food chains can be characterized and quantified for the purposes of ecological risk assessment.

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Preservation of genetic variation in the Green Lake strain lake trout derived from remnant domestic and feral populations

The Green Lake, Wisconsin, strain of lake trout Salvelinus namaycush was discontinued as a hatchery brood stock in 1976 after Lake Michigan was stocked with the 1975 year‐class. In 1982, a decision was made to restore the Green Lake strain as a production brood stock. Five groups were produced by spawning marked fish that were survivors from the 1976 stocking of southern Lake Michigan. A sixth group was produced from a remnant of the Green Lake brood stock held at the Genoa (Wisconsin) National Fish Hatchery. Hatchery accidents reduced both the number of groups and the effective population number of each group. We studied a procedure for reconstructing a composite Green Lake brood stock from individuals of these six groups. Genetic variability was evaluated by allozyme electrophoresis in five of these groups. Twelve of 18 loci were polymorphic. Allelic frequencies were similar in all five groups; however, significant differences occurred in nine systems. Heterozygosity level (mean ± SE) was lowest in the domestic group (0.119 ± 0.043) and ranged from 0.139 ± 0.043 to 0.166 ± 0.052 in the feral groups. Cluster analysis of genetic distances grouped the four feral groups together, but separate from the domestic group. Progeny from fish captured on Black Can Reef, Lake Michigan, in 1986 and 1988 were the most similar. A modified diallel mating design was developed to produce a composite brood stock from remnant feral and domestic fish. Pooled families from 1991 and 1992 diallel matings will be reared to maturity, then reciprocal crosses of the two year‐classes will be made to form the new composite Green Lake brood stock.

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