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Human dimensions considerations in wildlife disease management

In 1943, Aldo Leopold observed that the real problem of wildlife management is not how to handle wildlife, but how to manage humans. As with any other aspect of wildlife management, social sciences can improve understanding the human dimensions of wildlife disease management (WDM). Human activities have accelerated the emergence of wildlife diseases, and human concerns about the ecological, social, and economic impacts of wildlife diseases and their management have led to diseases becoming headline-worthy public issues. This chapter provides guidance to help front-line professionals understand and address the public’s perspectives and behaviors relevant to WDM. This chapter focuses on practical needs of wildlife disease managers who have to consider and interact with specific stakeholders and the broader public. The chapter does not dive deeply into social science; instead it briefly reviews some concepts that are most relevant to WDM. The chapter also suggests where to look for assistance and additional resources for further reading. Following brief introductory comments, the chapter is organized around a simple model of the general process for WDM. It addresses three key areas where social science can assist in WDM—audience research to understand stakeholders; engaging stakeholders in wildlife disease management; and using risk communication about wildlife diseases and disease management to inspire risk-wise behavior.

Techniques and Methods↗

A hydrologic primer for New Jersey watershed management

The U.S. Geological Survey (USGS) and the N.J. Department of Environmental Protection (NJDEP), and many other agencies and organizations are striving to educate the public about New Jersey’s water resources. In 1996, the NJDEP began implementing a “watershed management approach” to maintain the physical, chemical, and biological integrity of New Jersey’s waters. This approach concentrates on managing individual watershed areas by (1) defining the physical geographic boundaries of the watersheds, (2) basing water policy on sound scientific principles, and (3) developing partnerships with the public--the people most affected by watershed-management policies. New Jersey can be divided into five water regions as defined by the NJDEP: the Northeast, Raritan, Northwest, Lower Delaware, and Atlantic Coastal water regions (fig. 1). Each water region has been divided into three to five “watershed-management areas,” each of which encompasses a particular group of major rivers (fig. 2a-e). Each watershed management area consists of many smaller watersheds. Hydrologic data collected by Federal and State government agencies are invaluable as resources to policymakers who make decisions that affect the use of water in a particular watershed. The purpose of this report is to educate water-resource managers, policymakers, government officials, and the public about hydrologic concepts and the water-resource data needed to make informed decisions about water-management issues. (“Hydrologic” means relating to the occurrence, distribution, movement, and chemistry of all waters of the Earth (Fetter, 1980)). The first part of the report describes basic hydrologic concepts and includes explanations of the hydrologic cycle, the water budget, the surfacewater and ground-water flow systems, water-quality concepts and standards, and water use. The second part of the report summarizes the types of waterresource data that are available from Federal and State government agencies. Instructions on how to obtain the data and contact the appropriate Federal and State agencies, as well as suggestions for additional reading, also are included.

New Jersey↗

Pond-aquifer interaction at South Pond of Lake Cochituate, Natick, Massachusetts

A U.S. Army facility on a peninsula in South Pond of Lake Cochituate was designated a Superfund site by the U.S. Environmental Protection Agency in 1994 because contaminated ground water was detected at the facility, which is near the Natick Springvale public-supply wellfield. The interaction between South Pond and the underlying aquifer controls ground-water flow patterns near the pond and determines the source of water withdrawn from the wellfield.A map of the bathymetry and the thickness of fine-grained pond-bottom sediments was prepared on the basis of fathometer, ground-penetrating radar, and continuous seismic-reflection surveys. The geophysical data indicate that the bottom sediments are fine grained toward the middle of the pond but are coarse grained in shoreline areas. Natick Springvale wellfield, which consists of three active public-supply wells adjacent to South Pond, is 2,200 feet downgradient from the boundary of the Army facility. That part of South Pond between the Natick Springvale wellfield and the Army facility is 18 feet deep with at least 14 feet of fine-grained sediment beneath the pond-bottom. Water levels from the pond and underlying sediments indicate a downward vertical gradient and the potential for infiltration of pond water near the wellfield. Head differences between the pond and the wellfield ranged from 1.66 to 4.41 feet during this study. The velocity of downward flow from South Pond into the pond-bottom sediments, determined on the basis of temperature profiles measured over a diurnal cycle at two locations near the wellfield, was 0.5 and 1.0 feet per day. These downward velocities resulted in vertical hydraulic conductivities of 1.1 and 2.9 feet per day for the pond-bottom sediments.Naturally occurring stable isotopes of oxygen and hydrogen were used as tracers of pond water and ground water derived from recharge of precipitation, two potential sources of water to a well in a pond-aquifer setting. The isotopic composition of pond water varied seasonally and was distinctly different from the isotopic composition of ground water. The isotopic composition of shallow water beneath and adjacent to South Pond near the wellfield corresponds to the temporal variation of pond water, indicating that nearly all water at shallow depths was derived from pond water. A two-component mixing model based on the average stable isotope values of the source waters indicated that 64 ?15 percent at the 95-percent confidence interval of the water withdrawn at the public-supply wells was derived from the pond; pond water accounted for most of the uncertainty in the result. The rate of infiltration of pond water into the aquifer and discharging to the wellfield was 1.0 million gallons per day at the average pumping rate.

Water-Resources Investigations Report↗

Estimating the susceptibility of surface water in Texas to nonpoint-source contamination by use of logistic regression modeling

In the State of Texas, surface water (streams, canals, and reservoirs) and ground water are used as sources of public water supply. Surface-water sources of public water supply are susceptible to contamination from point and nonpoint sources. To help protect sources of drinking water and to aid water managers in designing protective yet cost-effective and risk-mitigated monitoring strategies, the Texas Commission on Environmental Quality and the U.S. Geological Survey developed procedures to assess the susceptibility of public water-supply source waters in Texas to the occurrence of 227 contaminants. One component of the assessments is the determination of susceptibility of surface-water sources to nonpoint-source contamination. To accomplish this, water-quality data at 323 monitoring sites were matched with geographic information system-derived watershed- characteristic data for the watersheds upstream from the sites. Logistic regression models then were developed to estimate the probability that a particular contaminant will exceed a threshold concentration specified by the Texas Commission on Environmental Quality. Logistic regression models were developed for 63 of the 227 contaminants. Of the remaining contaminants, 106 were not modeled because monitoring data were available at less than 10 percent of the monitoring sites; 29 were not modeled because there were less than 15 percent detections of the contaminant in the monitoring data; 27 were not modeled because of the lack of any monitoring data; and 2 were not modeled because threshold values were not specified.

Texas↗

The Southern Hills regional aquifer system of southeastern Louisiana and southwestern Mississippi

The Southern Hills regional aquifer system, named in a petition to the Environmental Protection Agency for designation as a sole or principal source of drinking water, is the primary source of public and domestic supplies in the northern 10 parishes of southeastern Louisiana. The gulfward dipping and thickening, complexly interbedded aquifer system extends from the northern limit of the recharge area near Vicksburg, Mississippi, as far as the Baton Rouge area in southeastern Louisiana. As many as 13 interdependent aquifer units compose the system in the southern part of the area and are known to coalesce or pinch out northward (updip) into fewer units. Aquifer water is almost exclusively a soft, sodium bicarbonate type with an average dissolved-solids concentration of about 220 milligrams per liter in southeastern Louisiana. Although several streams are available as alternatives for supply, they have not been accepted by local officials because of the additional water treatment that would be necessary and the extensive distribution system needed to deliver water to areas not near a source stream. Groundwater use in 1980 for public and domestic supply averaged 121 Mgal/d (million gallons per day), serving 744,000 people in southeastern Louisiana. In southwestern Mississippi, where the aquifer system is also the primary source for public and domestic supply, water use for these categories in 1980 totaled 25 Mgal/d, serving about 273,000 people. (USGS)

Water-Resources Investigations Report↗

Drought-related impacts on municipal and major self-supplied industrial water withdrawals in Tennessee -- Part A

A state-wide water use survey was conducted of all public water suppliers and large, self-supplied industries in Tennessee. This report contains a summation of the data received from 463 public-water suppliers and 129 self-supplied water users. Analysis of the study results and findings indicate that many communities in Tennessee do experience occasional water supply, quantity-related shortages. A total of 142 problems were reported by 107 of the public water suppliers. However, only 22 of the problems were a result of inadequate source supply. Although only three industries reported a water shortage problem , 20 were identified as having a potential water-supply source problem. West Tennessee was the only section of the state where all communities and industries surveyed reported an adequate water supply. The effects of a drought on the environment--specifically, wetlands, fish wildlife, and recreational-users--are briefly described, although there was no evidence that water withdrawn by communities or industry would directly affect the environment. This study appears to verify the conclusions that an extended drought, although directly affecting the supply to some communities and industries, may actually affect water quality and wastewater treatment more accurately by decreasing the ability of the source to assimilate wastes. (USGS)

Tennessee↗

Drought-related impacts on municipal and major self-supplied industrial water withdrawals in Tennessee -- Part B

A state-wide water use survey was conducted of all public water suppliers and large, self-supplied industries in Tennessee. This report contains a summation of the data received from 463 public-water suppliers and 129 self-supplied water users. Analysis of the study results and findings indicate that many communities in Tennessee do experience occasional water supply, quantity-related shortages. A total of 142 problems were reported by 107 of the public water suppliers. However, only 22 of the problems were a result of inadequate source supply. Although only three industries reported a water shortage problem , 20 were identified as having a potential water-supply source problem. West Tennessee was the only section of the state where all communities and industries surveyed reported an adequate water supply. The effects of a drought on the environment--specifically, wetlands, fish wildlife, and recreational-users--are briefly described, although there was no evidence that water withdrawn by communities or industry would directly affect the environment. This study appears to verify the conclusions that an extended drought, although directly affecting the supply to some communities and industries, may actually affect water quality and wastewater treatment more accurately by decreasing the ability of the source to assimilate wastes. (USGS)

Tennessee↗

Water demands in Kansas, 1944-84

The State of Kansas has administered water rights according to an appropriations doctrine since 1945. Water rights are issued by the Kansas State Board of Agriculture, Division of Water Resources, for eight categories of beneficial use. Water rights data and limited information on reported water use are stored on a computerized State data base; the U.S. Geological Survey cooperates with the State on maintenance of this system. This report analyzes trends in appropriations from 1944-84 for surface and groundwater for three major categories of use: irrigation, public supply, and industry. Demands for water, represented by these appropriations, are compared for three geographic areas within the State. These areas correspond to general patterns of water availability, population, and enterprises. As of 1984, 87% of the water appropriated for the three major types of use was for irrigation; most of this demand was for groundwater in the western one-third of the State. Seventy-five percent of the water demands in the central one-third of Kansas were met by groundwater; appropriations for irrigation represent the largest demand on water supplies in this area but must compete with appropriations for public supply and industry. Demands for surface water have increased substantially only in the eastern part of the State for industrial use and public supplies. The most prominent trends in water rights permit activity were related to climatic fluctuations, particularly the drought of the 1950's, legislative changes in the 1970 's requiring permits, and growth of urban populations in the central and eastern areas of the State. Analysis of trends in water appropriations can be useful in understanding the water issues facing Kansas in the future. (Author 's abstract)

Water-Resources Investigations Report↗

Water supplies in western Kentucky during 1984

An inventory was conducted between April and October 1985 of 101 major public supply systems and of self-supplied commercial and industrial water systems in a 27-county area in western Kentucky. These systems, because they withdraw at least 10,000 gal/day (gpd), are regulated by the Kentucky Natural Resources and Environmental Projection Cabinet (Division of Water) through a permitting program. The major purpose of the inventory was to evaluate the adequacy of these water systems to meet demands during times of drought. The inventory indicated that these systems withdrew 116.3 million gpd in 1984. The study showed that public facilities supplied 33.1 mil gpd to 471,500 people. Bowling Green Municipal Utilities in the Green River basin was the largest single public supplier. It supplied 5.05 million gpd to 48,000 people, and also sold over 1.7 million gpd to about 30 ,000 people through the Warren County Water System. Comparisons of ground- and surface-water use indicated the Lower Ohio River basin had the highest percentage of surface-water use at 97%, and the Mississippi River basin had the highest percentage of groundwater use at 41%. Sources of water were generally adequate throughout the study area. Sources for two industries, also in the Green River basin, are inadequate. Six systems may have potential problems with their treatment plant capacities because they are operating at > 80% of design capacity. Three of these systems are in the Green River basin, two are in the Lower Cumberland River basin, and one is in the Tennessee River basin. (Author 's abstract)

Water-Resources Investigations Report↗

Characteristics and properties of the basin-fill aquifer determined from three test wells west of Albuquerque, Bernalillo County, New Mexico

Three test wells were drilled west of Albuquerque; two are on the mesa west of the city, the third well is near the Rio Grande flood plain, west of the river. Test well 1, was drilled to a depth of 1,204 ft. Transmissivity of perforated intervals in the alluvial zone (980-1121 ft) ranged from 3.1 to 3.9 ft sq/day, and horizontal hydraulic conductivity from .02 to .03 ft/day. Vertical hydraulic conductivity of the semiconfining layer between the alluvial and volcanic zones is estimated to range from .00031 to .0031 ft/day. Transmissivity of the volcanic zone (1139-1179 ft) is about 81 ft sq/day, and horizontal hydraulic conductivity is about 2.0 ft/day. Dissolved-iron and manganese concentrations exceed recommended constituent limits for a public water supply. Vertical flow is upward; the potentiometric surface in the volcanic zone is about 2 ft higher than in the alluvial zone. Water levels are about 883 ft below land surface. Test well 2 was drilled to a depth of 1,828 ft below land surface with seven intervals open to the aquifer. During development, fine sand and silt entered the casing, filling it to a depth of 1,500 ft. The dissolved-cadmium concentration exceeds the maximum contaminant level and the dissolved-manganese concentration exceeds the recommended constituent limit for a public water supply. The vertical flow gradient is downward; the potentiometric surface in the middle and lower zones is about 17 ft lower than in the upper zones. Depth to water in the upper zone is about 767 below land surface and in the lower two zones the depth to water is about 784 ft below land surface. Test well 3 was drilled to a depth of 1,050 ft. Only the interval from 490 to 590 ft below land surface could be used to calculate transmissivity which was about 1,300 ft sq/day; horizontal hydraulic conductivity is about 13 ft/day. Quality of water is acceptable for a public water supply. Vertical flow is downward; the potentiometric surface in the deepest interval is about 7 ft lower than that in the uppermost zone. In the shallow interval from 350 to 590 ft below land surface, depth to water is about 24 ft below land surface. In the interval from 710 to 790 ft below land surface, depth to water is about 29 ft below land surface and in the interval from 870 to 1,050 ft below land surface, depth to water is 31 ft below land surface. (Author's abstract)

New Mexico↗

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Kendrick Reclamation Project Area, Wyoming, 1986-87

A reconnaissance investigation of the Kendrick Reclamation Project in central Wyoming was conducted during 1986-87 to determine if irrigation drainage has caused or has the potential to cause harmful effects on human health, fish, and wildlife, or other water uses. The investigation of the Kendrick Reclamation Project is one of nine similar investigations being conducted in the western conterminous United States as part of the Department of the Interior 's Irrigation Drainage Program. Samples of surface water were collected at 10 sites and ground water at 5 sites. Surface-water analyses included trace elements, radiochemicals, and pesticides. Concentrations in the water generally were less than national standards for public water supplies, with the exception of selenium. The median concentration of dissolved selenium was 7.5 microgm/L in 24 samples of surface and groundwater. Of the 11 samples that contained dissolved- selenium concentrations greater than the national standard for public water supplies of 10 microgm/L, 10 of the samples were collected at sites on streams that are not used for public water supplies; the eleventh sample was collected from a shallow well. Dissolved-selenium concentrations ranged from less than 1 to 300 microgm/L. Concentrations of dissolved selenium in the North Platte River, which supplies drinking water for several municipalities, ranged from less than 1 to 4 microgm/L. The dissolved-selenium concentration and selenium discharge in the North Platte River increased in the downstream direction. The four principal tributaries that receive drainage from the Kendrick Reclamation Project contributed substantially to the increase in selenium concentration and discharge in the North Platte River. Bottom-sediment samples from the North Platte River contained selenium contents of 1.2 microgm/g or less. (Author 's abstract)

Water-Resources Investigations Report↗

Water use in Kentucky, 1985

Water use information for 1985 was collected and reported by county for eight major categories of use. Seven of the categories were offstream uses, which included (1) public supply , (2) commercial, (3) domestic, (4) industrial, (5) mining, (6) thermoelectric, and (7) agricultural uses. The agricultural uses category was separated into irrigation and livestock water use. Instream water-use data also were collected for hydroelectric power generation. Water use in Kentucky was estimated to average 4,200 million gallons per day (M gal/d) during 1985 for all offstream uses. About 95% of this amount was from surface water sources, and about 5% was from groundwater sources. Per capita use for all offstream uses was about 1,100 gal/day. About 260 M gal/d was consumed (not returned to the surface--or groundwater system). Instream water use for hydroelectric power generation was estimated to be 91,000 M gal/d. Almost 97% of the offstream water withdrawals in 1985 were withdrawn for thermoelectric, public supply, and industrial use. Cooling water used in the production of thermoelectric power accounted for about 81% of the total offstream water use in 1985. Water withdrawn for public supplies was the second largest offstream use at about 10 % of the total, and industrial water use was almost 6%. Thermoelectric, domestic, and livestock uses accounted for almost 90% of the consumptive use in 1985. Consumptive use in the thermoelectric category was almost one-half of the total amount consumed in the State for all uses. (USGS)

Water-Resources Investigations Report↗

Description and evaluation of the effects of urban and agricultural development on the surficial aquifer system, Palm Beach County, Florida

The surficial aquifer system in Palm Beach County was studied during 1982-85 to determine the effects of increased urban and agricultural development on groundwater levels, flow directions, and quality. The surficial aquifer system and its geologic matrix are divisible into three zones on the bases of relative permeabilities and lithologic characteristics. The two greatest water users in the county, public supply utilities and agricultural irrigators, increased total water withdrawals by 123 and 50%, respectively, during 1970-80. By 1980, 76% of public supply withdrawals were from zones I and II of the surficial aquifer system, whereas groundwater pumpage for irrigation decreased to 9% of the total irrigation water used. Increases in groundwater withdrawals for public supply were greatest in the southeast and central coastal parts of the county and served as an indicator for potential changes of flow directions and water quality in the surficial aquifer system. Residual seawater, emplaced in the aquifer system during the Pleistocene Epoch, is still prevalent in the central and western parts of Palm Beach County where low permeabilities in the geologic matrix have retarded its dilution. Chemical analyses of canal-water and groundwater samples collected in April 1984 were used to evaluate the effects of groundwater/surface water exchange on the quality of water during canal conveyance across the area containing residual seawater.

Florida↗

Geohydrology and susceptibility of aquifers to surface contamination in Alabama; area 5

The U.S. Geological Survey, in cooperation with the Alabama Department of Environmental Management, is conducting a series of geohydrologic studies to delineate the major aquifers and their susceptibility to contamination in Alabama. This report delineates and describes the geohydrology and susceptibility of the major aquifers to contamination in Area 5--Chambers, Clay, Cleburne, Coosa, Lee, Randolph, and Tallapoosa Counties. Little groundwater is used for public water supplies in Area 5. Groundwater withdrawals for public supply in 1985 were 0.88 million gal/day. Most cities and towns that formerly used groundwater presently use surface water. None of the sedimentary rocks or unconsolidated deposits is tapped by public supply wells. None of the igneous and metamorphic rocks are considered a major aquifer because of low yields. Aquifers in the study area are susceptible to surface contamination throughout their entire outcrop area. Areas that are highly faulted and valley areas where groundwater is at or near land surface have potential to be highly susceptible to surface contamination. (USGS)

Water-Resources Investigations Report↗

Withdrawals and consumptive use of water in Pennsylvania, 1984

Total accountable water withdrawals in Pennsylvania during 1984 were 14,033.66 Mga/d (million gallons per day); of that total, 5.2 percent (729.53 Mgal/d) was supplied from ground-water sources in 94.8 percent (13,302.12 Mgal/d) was supplied from surface-water sources. Thermoelectric power generation accounted for 71 percent of the total withdrawals (10,010.60 Mgal/d); this was followed by self-supplied industry, 15 percent (2,055.63 Mgal/d); public supply, 11 percent (1,600.02 Mgal/d); mining (147.73 Mgal/d), self- supplied domestic use (131.63 Mgal/d), livestock and poultry (83.52 Mgal/d) and irrigation (4.52 Mgal/d) collectively made up 3 percent. Total consumptive use of water was 615.22 Mgal/d; self-supplied industry is responsible for the greatest consumptive use--185.53 Mgal/d. Trends in water withdrawals from 1950 to 1984 were examined for public supply, thermoelectric power generation and self-supplied industry. Total population and water withdrawals for public supply gradual increased in those years, whereas withdrawals for self-supplied industry and power generation increased until 1970 and then decreased.

Pennsylvania↗

Analysis of water surface and flow distribution for the design flood at a proposed highway crossing of the Sabine River near Tatum, Texas

The hydraulic effects of the proposed Texas Highway 43 crossing of the Sabine River near Tatum, Texas, were determined on the basis of results from a two-dimensional finite-element surface-water-flow model. In planning the replacement crossing by the Texas State Department of Highways and Public Transportation, approximations of apportionment of flow among the openings and velocities within the openings were of concern. The model was used to simulate flow in the river floodplain system for the proposed design, an alternate design, and for the natural condition. The proposed bridge design by the State Department of Highways and Public Transportation consisted of a 320-foot main channel opening, four left overflow bridges with widths of 120, 320, 320, and 280 feet, and one right overflow opening with a width of 440 feet. The alternate design consisted of a 950-foot main channel opening, three left overflow bridges with widths of 320, 320, and 280 feet, and one right overflow opening with a width of 200 feet. Preliminary one-dimensional computations were used as an aid in establishing the boundary conditions for the two-dimensional analysis. The analysis evaluates the interaction of complex hydraulic characteristics of varied features found at many multiple-opening highway crossings. Valid applications of accepted standard one-dimensional techniques would not reveal some aspects of the overall hydraulics of the crossing. The simulation of the proposed design shows, among other things, which openings are the most productive per foot of bridge length. The results of the two-dimensional simulation of the proposed design indicate some differences in the apportionment of flow among the openings when compared to the one-dimensional proposed crossing computations. The alternate design results in computed water-surface altitudes which were slightly lower than those of the proposed design. The alternate design would require less modification to the existing embankment. Velocities computed within the openings and at the bridge abutments, using the two-dimensional model, were within the design specifications of the State Department of Highways and Public Transportation. The simulations of the proposed and alternate designs indicate a lateral component of the water-surface slope at the embankment. Redistribution of flow across the floodplain also is indicated in both simulations. Some of the differences in the response between the two designs are affected by geometric features of the floodplain other than the embankment-opening geometry.

Water-Resources Investigations Report↗

Effects of combined-sewer overflows and urban runoff on the water quality of Fall Creek, Indianapolis, Indiana

In 1986, the U.S. Geological Survey and the Indianapolis Department of Public Works began a study to evaluate the effects of combined-sewer overflows and urban runoff discharging to Fall Geek on the White River. This report describes the effects of combined-sewer overflows and urban runoff on the water quality of Fall Creek during summer 1987 by comparing the water quality during base flow with that during storm runoff and by comparing water quality in the urbanized area with that in the less urbanized area upstream from the combined-sewer overflows. Data were collected at three streamflow-gaging stations located upstream from, downstream from, and in the middle of 27 combined-sewer overflows on Fall Creek. The most downstream station also was immediately downstream from the discharge of filter backwash from a water-treatment plant for public supply. Specific conductance and concentrations of major ions and dissolved solids in base flow increased downstream in response to surface-water withdrawn for public supply, ground-water inflow, and the discharge of filter backwash. Concentrations of dissolved oxygen were least in the reach of Fall Creek in the middle of the combined- sewer overflows where black sludge deposits covered the stream bottom. Concentrations of nitrate plus nitrite and ammonia steadily increased downstream, whereas concentrations of organic nitrogen, phosphorus, and orthophosphate only increased at the most downstream station. Nearly all concentrations of chromium, copper, lead, nickel, and zinc at the upstream and middle stations were less than the detection limit of 10 micrograms per liter. Detectable concentrations of these metals and high concentrations of suspended solids in base-flow samples at the most downstream station were caused by the discharges from the water-treatment plant. Concentrations of dissolved oxygen measured at the station in the middle of the combined-sewer overflows were less than the Indiana minimum ambient water-quality standard of 4.0 milligrams per liter during all storms. Concentrations of ammonia, oxygen demand, copper, lead, zinc, and fecal coliform bacteria at the stations downstream from the combined-sewer overflows were much higher in storm runoff than in base flow. Increased concentrations of oxygen demand in runoff probably were caused by combined-sewer overflows, urban runoff, and the resuspension of organic material deposited on the streambed. Some of the increased concentrations of lead, zinc, and probably copper can be attributed to the discharge and resuspension of filter backwash

Indiana↗

National water quality assessment of the Georgia-Florida Coastal Plain study unit — Water withdrawals and treated wastewater discharges, 1990

The Georgia-Florida Coastal Plain study unit covers nearly 62,600 square miles along the southeastern United States coast in Georgia and Florida. In 1990, the estimated population of the study unit was 9.3 million, and included all or part of the cities of Atlanta, Jacksonville, Orlando, Tampa, and St. Petersburg. Estimated freshwater withdrawn in the study unit in 1990 was nearly 5,075 million gallons per day. Ground-water accounted for more than 57 percent of the water withdrawn during 1990 and the Floridan aquifer system provided nearly 91 percent of the total ground-water withdrawn. Surface-water accounted for nearly 43 percent of the water withdrawn in the study unit in 1990 with large amounts of withdrawals from the Altamaha River, Hillsborough River, the Ocmulgee River, the Oconee River, the St. Johns River, and the Suwannee River. Water withdrawn for public supply in the Georgia-Florida Coastal Plain study unit in 1990 totaled 1,139 million gallons per day, of which 83 percent was ground water and 17 percent was surface water. Self-supplied domestic withdrawals in the Georgia-Florida Coastal Plain study unit in 1990 totaled nearly 230 million gallons per day. Ground water supplied over 80 percent of the study units population for drining water purposes; nearly 5.8 million people were served by public supply and 1.8 million people were served by self-supplied systems. Water withdrawn for self-supplied domestic use in Georgia and Florida is derived almost exclusively from ground water, primarily because this source can provide the quantity and quality of water needed for drinking purposes. Nearly 1.7 million people served by public supply utilized surface water for their drinking water needs. Water withdrawn for self-supplied commercial-industrial uses in the study unit in 1990 totaled 862 million gallons per day, of which 93 percent was ground water and 7 percent was surface water. Water withdrawn for agriculture purposes in the study unit in 1990 totaled 1,293 million gallons per day, of which 69 percent was ground water and 31 percent was surface water. An estimated 1.254 millon acres were irrigated within the study unit during 1990. Water withdrawn for thermoelectric power generation in the study unit in 1990 totaled 1,552 million gallons per day, of which 99 percent was surface water and 1 percent was ground water. An additional 6,919 million gallons per day of saline surface water were withdrawn for thermoelectric power generation in 1990, solely for cooling purposes. Treated wastewater discharged within the Georgia-Florida Coastal Plain study unit totaled nearly 1,187 million gallons per day in 1990. Of the total water discharged, 58 percent was discharged directly into surface water and the remaining 42 percent was discharged to ground water (through drain fields, injection wells, percolation ponds or spray fields). Domestic wastewater facilities discharged in the study unit totaled nearly 789 million gallons per day, industrial wastewater facilities discharged 213 million gallons per day, and releases from septic tanks was estimated at 185 million gallons per day. More than 1.3 million septic tanks were estimated in use within the study unit in 1990.

Florida, Georgia↗