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Geologic and well-construction data for the H-10 borehole complex near the proposed Waste Isolation Pilot Plant site, southeastern New Mexico

The H-10 borehole complex, a group of three closely spaced boreholes, is located 3 1/2 miles southeast of the proposed Waste Isolation Pilot Plant site in west-central Lea County, New Mexico. The geological data presented in this report are part of a site-characterization study for the possible storage of defense-associated radioactive wastes within salt beds of the Salado Formation of Permian age. Each borehole was designated to penetrate a distinct water-bearing zone: H-10a (total depth 1 ,318 feet) was completed just below the Magenta Dolomite Member of the Rustler Formation of Permian age; H-10b (total depth 1 ,398 feet) was completed just below the Culebra Dolomite Member of the Rustler Formation; and H-10c (total depth 1,538 feet) was completed below the Rustler Formation-Salado Formation contact. The geologic units penetrated in borehole H-10c are surficial alluvium and eolian sand of Holocene age (0-5 feet); the Mescalero caliche (5-9 feet) and the Gatuna Formation (9-90 feet) of Pleistocene age; formation in the Dockum Group (Chinle Formation, 90-482 feet and Santa Rosa Sandstone, 482-658 feet) of Late Triassic age; and the Dewey Lake Red Beds (658-1,204 feet), the Rustler Formation (1,204-1,501 feet), and part of the Salado Formation (1,501-1,538 feet), all of Permian age. The sections of the Rustler and Salado Formations penetrated by borehole H-10c are complete and contain little or no evidence of dissolution of halite and associated rocks, indicating that the eastward-moving dissolution on top of the Salado, found just to the west of the WIPP site, has not reached the H-10 site. (USGS)

Water-Resources Investigations Report↗

Using water-quality profiles to characterize seasonal water quality and loading in the upper Animas River basin, southwestern Colorado

One of the important types of information needed to characterize water quality in streams affected by historical mining is the seasonal pattern of toxic trace-metal concentrations and loads. Seasonal patterns in water quality are estimated in this report using a technique called water-quality profiling. Water-quality profiling allows land managers and scientists to assess priority areas to be targeted for characterization and(or) remediation by quantifying the timing and magnitude of contaminant occurrence. Streamflow and water-quality data collected at 15 sites in the upper Animas River Basin during water years 1991?99 were used to develop water-quality profiles. Data collected at each sampling site were used to develop ordinary least-squares regression models for streamflow and constituent concentrations. Streamflow was estimated by correlating instantaneous streamflow measured at ungaged sites with continuous streamflow records from streamflow-gaging stations in the subbasin. Water-quality regression models were developed to estimate hardness and dissolved cadmium, copper, and zinc concentrations based on streamflow and seasonal terms. Results from the regression models were used to calculate water-quality profiles for streamflow, constituent concentrations, and loads. Quantification of cadmium, copper, and zinc loads in a stream segment in Mineral Creek (sites M27 to M34) was presented as an example application of water-quality profiling. The application used a method of mass accounting to quantify the portion of metal loading in the segment derived from uncharacterized sources during different seasonal periods. During May, uncharacterized sources contributed nearly 95 percent of the cadmium load, 0 percent of the copper load (or uncharacterized sources also are attenuated), and about 85 percent of the zinc load at M34. During September, uncharacterized sources contributed about 86 percent of the cadmium load, 0 percent of the copper load (or uncharacterized sources also are attenuated), and about 52 percent of the zinc load at M34. Characterized sources accounted for more of the loading gains estimated in the example reach during September, possibly indicating the presence of diffuse inputs during snowmelt runoff. The results indicate that metal sources in the upper Animas River Basin may change substantially with season, regardless of the source.

Colorado↗

Comparison of selected cultural, physical, and water-quality characteristics of lakes in Washington

This report presents comparisons and a graphical overview of the relative magnitude and the regional and statewide distribution of 19 selected cultural, physical, and water-quality characteristics measured in a reconnaissance study of several hundred lakes in Washington. The selected characteristics presented for each lake include types of land use in the lake drainage basin, shoreline residential development, altitude of lake, mean lake depth, nitrogen and phosphorus concentrations in upper and bottom waters, specific conductance, temperature and dissolved-oxygen concentration cf bottom water, Secchi-disc visibility, emersed macrophytes covering shoreline and lake surface, and fecal-coliform bacteria. Statewide, about two-thirds of the lake drainage basins studied have more than half their land in forest. Urban and suburban developments of the basins are highest in the more populated western Washington counties near Puget Sound, whereas most land in the drainage basins of lakes in the Columbia Plateau of eastern Washington is used for agricultural purposes. Statewide, almost one-fourth of the lakes are shallow (mean depth 2.0 meters or less) and only 7 percent of the lakes have mean depths greater than 20 meters. Dissolved-oxygen layering in summer was detected in many lakes throughout the State. The oxygen concentrations in the upper waters of these lakes were typically near saturation, but the bottom waters of many were severely depleted. Statewide, about one-third of the lakes had Secchi-disc readings of 2.0 meters or less, a value often considered characteristic of eutrophic lakes. The poorest water clarity was observed in the Columbia Plateau, where 68 percent of the lakes had Secchi-disc readings of less than 2.0 meters. Statewide, the median concentration of total phosphorus in the upper waters of lakes was 20 micrograms per liter. More than one-third of the lakes in the State had total phosphorus concentrations in their upper waters that exceeded 30 micrograms per liter, a concentration that is often considered characteristic of eutrophic lakes.

Washington↗

Stratigraphic and hydrogeologic framework of the Alabama Coastal Plain

Tertiary and Cretaceous sand aquifers of the Southeastern United States Coastal Plain comprise a major multlstate aquifer system informally defined as the Southeastern Coastal Plain aquifer system, which is being studied as part of the U.S. Geological Survey's Regional Aquifer System Analysis (RASA) program. The major objectives of each RASA study are to identify, delineate, and map the distribution of permeable clastlc rock, to examine the pattern of ground-water flow within the regional aquifers, and to develop digital computer simulations to understand the flow system. The Coastal Plain aquifers in Alabama are being studied as a part of this system. This report describes the stratlgraphlc framework of the Cretaceous, Tertiary, and Quaternary Systems in Alabama to aid in delineating aquifers and confining units within the thick sequence of sediments that comprises the Southeastern Coastal Plain aquifer system in the State. Stratigraphlc units of Cretaceous and Tertiary age that make up most of the aquifer system in the Coastal Plain of Alabama consist of clastlc deposits of Early Cretaceous age; the Coker and Gordo Formations of the Tuscaloosa Group, Eutaw Formation, and Selma Group of Late Cretaceous age; and the Midway, Wilcox, and Clalborne Groups of Tertiary age. However, stratigraphlc units of late Eocene to Holocene age partially overlie and are hydraulically connected to clastic deposits in southern Alabama. These upper carbonate and clastlc stratlgraphic units also are part of the adjoining Florldan and Gulf Coastal Lowlands aquifer systems. The Coastal Plain aquifer system is underlain by pre-Cretaceous rocks consisting of low-permeabillty sedimentary rocks of Paleozolc, Triassic, and Jurassic age, and a complex of metamorphic and igneous rocks of Precambrian and Paleozolc age similar to those found near the surface in the Piedmont physiographic province. Twelve hydrogeologlc units in the Alabama Coastal Plain are defined--slx aquifers and six confining units. Aquifers of the Coastal Plain aquifer system are composed of fine to coarse sand, gravel, and limestone; confining beds are composed of clay, shale, chalk, marl, and metamorphic and igneous rocks.

Water-Resources Investigations Report↗

Estimating the magnitude and frequency of low flows of streams in Massachusetts

The report presents techniques used for estimating 7-day 2-year (7Q2) and 7-day 10-year (7Q10) flows at continuous-record streamflow-gaging stations, partial-record stations, and ungaged sites on streams in Massachusetts. A two-parameter log-normal probability distribution was used to compute low flows at 31 continuous-record stream-flow-gaging stations. Graphical and mathematical techniques were used to estimate low flows at partial-record stations. Regional regression techniques commonly are used to estimate 7Q2 and 7Q10 flows at ungaged stream sites. The development and application of a low-flow regression model is described. The model contains two parameters, mean and standard deviation, computed from separate regression equations that use total drainage area and basin relief as independent variables. The coefficients of determination of the mean and standard deviation regression equations are 0.964 and 0.960, respec- tively; the percentage of standard error of the regression of each equation are 35 and 34, respec- tively. The model is applicable for basins in Massachusetts having a drainage area of 5 to 150 square miles, a slope of less than 4 percent, and an area of stratified drift greater than 4 percent of the total drainage area. A computer program is presented that can be used to compute 7Q2 and 7Q10 flows and the 95-percent intervals of confidence and prediction for a given basin.

Water-Resources Investigations Report↗

Water-quality assessment of the Central Arizona Basins, Arizona and northern Mexico – Environmental setting and overview of water quality

The Central Arizona Basins study area in central and southern Arizona and northern Mexico is one of 60 study units that are part of the U.S. Geological Survey's National Water-Quality Assessment program. The purpose of this report is to describe the physical, chemical, and environmental characteristics that may affect water quality in the Central Arizona Basins study area and present an overview of water quality. Covering 34,700 square miles, the study area is characterized by generally north to northwestward-trending mountain ranges separated by broad, gently sloping alluvial valleys. Most of the perennial rivers and streams are in the northern part of the study area. Rivers and streams in the south are predominantly intermittent or ephemeral and flow in response to precipitation such as summer thunderstorms. Effluent-dependent streams do provide perennial flow in some reaches. The major aquifers in the study area are in the basin-fill deposits that may be as much as 12,000 feet thick. The 1990 population in the study area was about 3.45 million, and about 61 percent of the total was in Maricopa County (Phoenix and surrounding cities). Extensive population growth over the past decade has resulted in a twofold increase in urban land areas and increased municipal water use; however, agriculture remains the major water use. Seventy-three percent of all water with drawn in the study area during 1990 was used for agricultural purposes. The largest rivers in the study area-the Gila, Salt, and Verde-are perennial near their headwaters but become intermittent downstream because of impoundments and artificial diversions. As a result, the Central Arizona Basins study area is unique compared to less arid basins because the mean surface-water outflow is only 528 cubic feet per second from a total drainage area of 49,650 square miles. Peak flows in the northern part of the study area are the result of snowmelt runoff; whereas, summer thunderstorms account for the peak flows in the southern part. Ground water is the primary water supply in most of Arizona and the only source of drinking water used by communities in the southern half of the study area. Years of overpumping have caused water tables in basin fill to drop below once-perennial streams leaving streambeds dry, water too deep to pump economically, pumping of poorer quality water with depth, and earth fissures resulting from subsidence after dewatering of sediments. Natural processes-such as leaching of trace elements and major ions from geologic formations-and human activities-such as mining, agriculture, and urban development-have major effects on the quality of surface-water and ground-water resources in the Central Arizona Basins study area. Surface-water quality standards in Arizona are based on the designated use of the water such as full or partial body contact, fish consumption, aquatic and wildlife uses, and agriculture. Maintaining the biological integrity (health) of surface waters in Arizona is an important part of ensuring that these waters are suitable for designated uses. Important water-quality issues for surface water that are somewhat unique to Arizona include: (1) streamflows and riparian environments sustained by effluent from municipal wastewater-treatment plants that contains high concentrations of nutrients, potentially toxic trace elements and organic compounds, and fecal bacteria; (2) industrial, mining, agricultural, and municipal sources of contamination from Mexico; and (3) unpredictable high flows from major summer thunder storms causing stream-channel changes; high suspended-sediment concentrations and loads; sewage overflows; and breaching, erosion, and washout of landfills and mining operations. The quality of water in aquifers that are protected for drinking- water use is subject to standards that are in most cases equal to or more stringent than the primary drinking-water regulations of the U.S. Environmental Protection Agency. The general che

Arizona↗

Hydrology and water quality of the Edwards Aquifer associated with Barton Springs in the Austin area, Texas

Urban development over the Edwards aquifer in the Austin, Texas, area has caused concerns about the availability and quality of water in the aquifer. The study area, the Edwards aquifer that discharges to Barton Springs, includes parts of Travis and Hays Counties and extends from the city of Kyle to the Colorado River. A large part of the aquifer lies within the Austin metropolitan area one of the fastest growing areas in the Nation. As of 1985, only about 30,000 people used water from the aquifer, however, according to recent official city of Austin population projections, about 86,000 more people will be living in the study area by the year 2000, many of whom will depend upon the aquifer for water. Barton Springs, which discharges from the aquifer, serves as a supplemental source of drinking water for Austin and as a major recreational attraction. The aquifer is a karst system composed of limestone and dolomite of Cretaceous age. The water occurs in solution channels in the Edwards and Georgetown Limestones. Yields of adjacent wells often differ by as much as four orders of magnitude. Storage within the aquifer is about 306,000 acre-feet, of which about 31,000 acre-feet is within the "transient" part of storage the change in volume occurring between high flow and the lowest known flow of Barton Springs. The average specific yield of the aquifer is 0.017. Within the study area, the Edwards aquifer covers 155 square miles, of which about 151 square miles discharge to Barton Springs, and the remaining 4 square miles discharge to Cold and Deep Eddy Springs. The westernmost 79 percent of the aquifer is under water-table conditions, and the remaining 21 percent is under confined conditions. Three geologic sections are presented in the report, as well as maps showing the altitudes of the base and the top of the Edwards aquifer. Recharge occurs predominantly along faults and fractures crossing six creeks in the recharge area, which covers the westernmost 90 square miles of the aquifer. Leakage probably occurs into the Edwards aquifer from the underlying upper Trinity aquifer. A small amount of subsurface recharge also occurs as "bad-water" encroachment during lovnflow periods. Monthly values for water levels, total surface-water recharge, and total discharge (springflow and pumpage) for the aquifer are available for 4 years. Water-budget analyses show that surface recharge and ground-water discharge (springflow and pumpage) are reasonably balanced, suggesting that the ground-water system is in dynamic equilibrium. Based on 65 years of measurements, Barton Springs has a long-term mean discharge of 50 cubic feet per second and a minimum and maximum discharge of 10 and 166 cubic feet per second. As of 1982, the estimated total ground-water pumpage of about 3,800 acre-feet per year represented just over 10 percent of the average annual discharge of 36,000 acre-feet to Barton Springs. Increased pumpage associated with future ground-water development could reduce the discharge at Barton Springs and reduce ground-water availability. Substantial pumpage increases could cause increased subsurface flow into the aquifer in the form of "bad-water" encroachment, leakage from underlying aquifers, or both. Water-quality data for 1979-83 are available for each creek that recharges the aquifer, from Barton Springs, and for 38 wells. Water quality from Barton Springs and the wells is better than the creeks providing surface recharge, which have fecal-bacteria values as high as 100,000 colonies per 100 milliliters. Significant densities of fecal bacteria have been found in water from Barton Springs. Significant concentrations of nitrate nitrogen, fecal-group bacteria, and fluoride have been identified in samples from wells. Fluoride originates in the aquifers that underlie the Edwards aquifer. Nitrate nitrogen and fecal-group bacteria originate in residential developments and cattle ranches located in the area.

Texas↗

Results of quality-control sampling of water, bed sediment, and tissue in the Western Lake Michigan Drainages study unit of the National Water-Quality Assessment Program

This report contains the quality control results of the Western Lake Michigan Drainages study unit of the National Water Quality Assessment Program. Quality control samples were collected in the same manner and contemporaneously with environmental samples during the first highintensity study phase in the unit (1992 through 1995) and amounted to approximately 15 percent of all samples collected. The accuracy and precision of hundreds of chemical analyses of surface and ground-water, bed sediment, and tissue was determined through the collection and analysis of field blanks, field replicates and splits, matrix spikes, and surrogates. Despite the several detections of analytes in the field blanks, the concentrations of most constituents in the environmental samples will likely be an order of magnitude or higher than those in the blanks. However, frequent detections, and high concentrations, of dissolved organic carbon (DOC) in several surface and ground-water blanks are probably significant with respect to commonly measured environmental concentrations, and the environmental data will have to be qualified accordingly. The precision of sampling of water on a percent basis, as determined from replicates and splits, was generally proportional to the concentration of the constituents, with constituents present in relatively high concentrations generally having less sampling variability than those with relatively low concentrations. In general, analytes with relatively high variability between replicates were present at concentrations near the reporting limit or were associated with relatively small absolute concentration differences, or both. Precision of replicates compared to that for splits in bed sediment samples was similar, thus eliminating sampling as a major source of variability in analyte concentrations. In the case the phthalates in bed sediment, contamination in either the field or laboratory could have caused the relatively large variability between replicate samples and between split samples.Variability of analyte concentrations in tissue samples was relatively low, being 29 percent or less for all constituents. Recoveries of most laboratory schedule 2001/2010 pesticide spike compounds in surfacewater samples were reasonably good. Low intrinsic method recovery resulted in relatively low recovery forp,p'-DDE, metribuzin, and propargite. In the case of propargite, decomposition with the environmental sample matrices was also indicated. Recoveries of two compounds, cyanazine and thiobencarb, might have been biased high due to interferences. The one laboratory schedule 2050/2051 field matrix pesticide spike indicated numerous operational problems with this method that biased recoveries either low or high. Recoveries of pesticides from both pesticide schedules in field spikes of ground-water samples generally were similar to those of field matrix spikes of surface- water samples. High maximum recoveries were noted for tebuthiuron, disulfoton, DCPA, and permethrin, which indicates the possible presence of interferents in the matrices for these compounds. Problems in the recoveries of pesticides on schedule 2050/2051 from ground-water samples generally were the same as those for surfacewater samples. Recoveries of VOCs in field matrix spikes were reasonable when consideration was given for the use of the micropipettor that delivered only about 80 percent on average of the nominal mass of spiked analytes. Finally, the recoveries of most surrogate compounds in surface and ground-water samples were reasonable. Problems in sample handling (for example, spillage) were likely not the cause of any of the low recoveries of spiked compounds.

Michigan, Wisconsin↗

Hydrogeology of the western part of the Salt River Valley area, Maricopa County, Arizona

The Salt River Valley is a major population and agricultural center of more than 3,000 mi 2 in central Arizona (fig. 1). The western part of the Salt River Valley area (area of this report) covers about 1,500 mi 2 . The Phoenix metropolitan area with a population of more than 1.6 million in 1985 (Valley National Bank, 1987) is located within the valley. The watersheds of the Salt, Verde, and Agua Fria Rivers provide the valley with a reliable but limited surface-water supply that must be augmented with ground water even in years of plentiful rainfall. Large-scale ground-water withdrawals began in the Salt River Valley in the early part of the 20th century; between 1915 and 1983, the total estimated ground-water pumpage was 81 million acre-ft (U.S. Geological Survey, 1984). Because of the low average annual rainfall and high potential evapotranspiration, the principal sources of ground-water recharge are urban runoff, excess irrigation, canal seepage and surface-water flows during years of higher-than-normal rainfall. Withdrawals greatly exceed recharge and, in some area, ground-water levels have declines as much as 350 ft (Laney and other, 1978; Ross, 1978). In the study area, ground-water declines of more than 300 ft have occurred in Deer Valley and from Luke Air Force Base north to Beardsley. As a result, a large depression of the water table has developed west of Luke Air Force Base (fig. 2). Ground-water use has decreased in recent years because precipitation and surface-water supplies have been greater than normal. Increased precipitation also caused large quantities of runoff to be released into the normally dry Salt and Gila River channels. From February 1978 to June 1980, streamflow losses of at least 90,000 acre-ft occurred between Jointhead Dam near the east boundary of the study area and Gillespie Dam several miles southwest of the west edge of the study area (Mann and Rhone, 1983). Consequently, ground-water declines in a large part of the basin have slowed, and ground-water levels in some sarea have risen significantly. In many areas along the Salt River and northeast of the confluence of the Salt and Agua Fria River, ground-water levels rose more than 25 ft between 1978 and 1984 (Reeter and Remick, 1986).

Arizona↗

Use of environmental tracers to evaluate ground-water age and water-quality trends in a buried-valley aquifer, Dayton area, southwestern Ohio

Chlorofluorocarbons (CFC method) and tritium and helium isotopes (3H-3He method) were used as environmental tracers to estimate ground-water age in conjunction with efforts to develop a regional ground-water flow model of the buried-valley aquifer in the Dayton area, southwestern Ohio. This report describes results of CFC and water-quality sampling, summarizes relevant aspects of previously published work, and describes the use of 3H-3He ages to characterize temporal trends in ground-water quality of the buried-valley aquifer near Dayton, Ohio. Results of CFC sampling indicate that approximately 25 percent of the 137 sampled wells were contaminated with excess CFC's that rendered the ground water unsuitable for age dating. Evaluation of CFC ages obtained for the remaining samples indicated that the CFC compounds used for dating were being affected by microbial degradation. The degradation occurred under anoxic conditions that are found in most parts of the buried-valley aquifer. As a result, ground-water ages derived by the CFC method were too old and were inconsistent with measured tritium concentrations and independently derived 3H-3He ages. Limited data indicate that dissolved methane may play an important role in the degradation of the CFC's. In contrast, the 3H-3He technique was found to yield ground-water ages that were chemically and hydrologically reasonable. Ground-water ages derived by the 3H-3He technique were compared to values for selected water- quality characteristics to evaluate temporal trends in ground-water quality in the buried- valley aquifer. Distinct temporal trends were not identified for pH, alkalinity, or calcium and magnesium because of rapid equilibration of ground-water with calcite and dolomite in aquifer sediments. Temporal trends in which the amount of scatter and the number of outlier concentrations increased as ground-water age decreased were noted for sodium, potassium, boron, bromide, chloride, ammonia, nitrate, phosphate, sulfate, and organic carbon. Elevated concentrations of these constituents in shallow ground water are probably related to human activities. Temporal trends in which concentrations declined as ground-water age increased may reflect natural processes that reduce constituent concentrations to low levels. For example, the absence of nitrate detections in ground water recharged before 1980 may indicate natural removal of nitrate by bacterially mediated denitrification. Temporal trends observed for dissolved oxygen, iron, nitrate and silica indicate that these constituents may help identify recently (post-1990) recharged ground water.

Ohio↗

Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Klamath Basin, California and Oregon, 1990-92

The effect of irrigation drainage on the water quality and wildlife of the Klamath Basin in California and Oregon was evaluated during 1990-92 as part of the National Irrigation Water Quality Program of the U.S. Department of the Interior. The study focused on land serviced by the Bureau of Reclamation Klamath Project, which supplies irrigation water to agricultural land in the Klamath Basin and the Lost River Basin. The Tule Lake and Lower Klamath National Wildlife Refuges, managed by the U.S. Fish and Wildlife Service, are in the study area. These refuges provide critical resting and breeding habitat for waterfowl on the Pacific flyway and are dependent on irrigation drainwater from upstream agriculture for most of their water supply. Water-quality characteristics throughout the study area were typical of highly eutrophic systems during the summer months of 1991 and 1992. Dissolved-oxygen concentrations and pH tended to fluctuate each day in response to diurnal patterns of photosynthesis, and frequently exceeded criteria for protection of aquatic organisms. Nitrogen and phosphorus concentrations were generally at or above threshold levels characteristic of eutrophic lakes and streams. At most sites the bulk of dissolved nitrogen was organically bound. Elevated ammonia concentrations were common in the study area, especially downstream of drain inputs. High pH of water increased the toxicity of ammonia, and concentrations exceeded criteria at sites upstream and downstream of irrigated land. Concentrations of ammonia in samples from small drains on the Tule Lake refuge leaseland were higher than those measured in the larger, integrating drains at primary monitoring sites. The mean ammonia concentration in leaseland drains [1.21 milligrams per liter (mg/L)] was significantly higher than the mean concentration in canals delivering water to the leaseland fields (0.065 mg/L) and higher than concentrations reported to be lethal to Daphnia magna (median lethal concentration of 0.66 mg/L). Dissolved-oxygen concentrations also were lower, and Daphnia survivability measured during in situ bioassays was correspondingly lower in the leaseland drains than in water delivery canals. In static laboratory bioassays, water samples collected at the primary monitoring sites caused toxicity in up to 78 percent of Lemna minor tests, in up to 49 percent of Xenopus laevis tests, in 17 percent and 8 percent of Hyalella azteca and Pimephales promelas tests, respectively, and 0 percent in Daphnia magna tests. In situ exposure at the sites caused mortality in more than 83 percent of Pimephales tests and in more than 41 percent of Daphnia and Hyalella tests. Much of the observed toxicity appears to have been caused by low dissolved oxygen, high pH, and ammonia. Although water in the study area was toxic to a variety of organisms, no statistically significant differences in the degree of toxicity between sites were observed above or below irrigated agricultural land in any of the bioassays. Pesticides were frequently detected in water samples collected at the monitoring sites during the 1991 and 1992 irrigation seasons. Among the most frequently detected compounds were the herbicides simazine, metribuzin, EPTC, and metolachlor and the insecticide terbufos. All the insecticides detected were at concentrations substantially below acute toxicity values reported for aquatic organisms. The herbicide acrolein has been used extensively in the basin to manage aquatic plant growth in irrigation canals and drains. The concentration of acrolein was monitored in a canal near Tule Lake after an application in order to evaluate the potential for the pesticide to be transported to refuge waters. Although acrolein concentrations were toxic to fish in the channels adjacent to Tule Lake, very little of the canal water entered the refuge during the monitoring period. Organochlorine pesticide concentrations in 25 surficial sediment samples collected in 1990 were below baseline levels commonly found in soils and sediment. Seventeen sediment samples were analyzed for chlorophenoxy acid herbicides and two samples were analyzed for organophosphorus and carbamate insecticides in 1992. No pesticides were detected in any of these samples. Residues of the trace elements selenium, mercury, and arsenic in algae, invertebrates, fish, and avian eggs revealed no bioaccumulation problems. Concentrations of organochlorine compounds, especially of p,p' DDE, were associated with a mean 11-percent eggshell thinning in white-faced ibis. However, ibis populations appear to be increasing, and some eggs of ibis were relatively low in DDE concentration. DDE concentrations in eggs of western grebes were not as high as in the eggs of ibis. Concentrations and types of organochlorine compounds detected in grebe and ibis eggs were highly variable, indicating that the birds were exposed to these compounds outside the basin. Fish and invertebrates inhabiting drainwater were representative of pollution-tolerant species assemblages. The aquatic communities retained little of their historic ecological structure. Extensive hydrologic modifications and hypereutrophic conditions in Klamath Basin waterways have degraded the quality of aquatic habitat and altered aquatic communities.

California, Oregon↗

Delineation of the Troy Bedrock Valley and particle-tracking analysis of ground-water flow underlying Belvidere, Illinois

The U.S. Geological Survey, U.S. Environmental Protection Agency, and Illinois Environmental Protection Agency began a study of the hydrogeology, flow system, and distribution of contaminants in the aquifers underlying Belvidere, Ill., and vicinity in 1992. As part of the study, the ancestral Troy Bedrock Valley, located about 1.5 miles west of Belvidere, was identified as an important part of the ground-water-flow system. In the deepest parts of the valley, the basal Glenwood confining unit may be absent; thick deposits of sand and gravel that infill part of the valley may directly overlie the sandstone St. Peter aquifer, a regionally important source of water for public supply. With few deep wells open to the St. Peter aquifer present in the valley to provide necessary geologic information, tritium and other water-chemistry data were collected from eight wells to possibly delineate areas where the confining unit may be absent; the data also provide baseline water-quality information for an area expecting changes in land use and increases in water withdrawal. Also as part of the study, particle-tracking analysis was done using an available flow model to (1) identify possible discharge locations of ground water and contaminants and (2) delineate areas contributing recharge to the Belvidere municipal wells. This report presents and interprets water-chemistry data collected during December 2000 and presents results of particle-tracking analysis. Ground water in samples from two of four wells open to the St. Peter aquifer appears to have recharged after 1954, suggesting that the Glenwood confining unit may be absent near the wells. Other hydrogeologic and water-chemistry data, however, were inconclusive or contradictory. Concentrations of iron, manganese, and lead exceeded maximum contaminant levels in five or less samples, but materials associated with the water-distribution systems appear to contribute to the elevated concentrations above natural levels. Particle-tracking analysis indicates that most ground-water flow beneath possible contaminant-source areas discharges from the glacial drift aquifer to the Kishwaukee River. Most of the source areas are in or near Belvidere and are within 1,500 feet of the river. The analysis also indicates the possibility that in parts of the study area, some ground water does not discharge to the river, but flows beneath the Kishwaukee River in the underlying carbonate Galena-Platteville aquifer. Ground water that discharges to the one municipal well open to the glacial drift aquifer is estimated to travel over 1 mile in less than 25 years. Simulated residence (travel) times of ground water from the base of the glacial drift aquifer to the six municipal wells open, in part, to the Galena-Platteville aquifer, are estimated at less than about 40 years. Because fractures in this aquifer are unaccounted for in the flow model, actual areas contributing recharge are likely larger and travel times faster than those simulated for most of the municipal wells. Tritium data indicate that, in general, travel times from the land surface to the deepest parts of the Galena-Platteville aquifer are less than 46 years. Methyl tertiary-butyl ether data indicate that travel times to the upper part of the aquifer may be less than 16 years. The water-quality-based estimates of travel time generally are consistent with the estimates from particle-tracking analysis.

Illinois↗

Methods for estimating monthly mean concentrations of selected water-quality constituents for stream sites in the Red River of the North basin, North Dakota and Minnesota

Future development of the Garrison Diversion Unit may divert water from the Missouri River into the Sheyenne River and the Red River of the North for municipal and industrial use. The U.S. Bureau of Reclamation's Canals, Rivers, and Reservoirs Salinity Accounting Procedures model can be used to predict the effect various operating plans could have on water quality in the Sheyenne River and the Red River of the North. The model uses, as Input, monthly means of streamflow and selected water-quality constituents for a 54-year period at 28 nodes on the Sheyenne River and the Red River of the North. This report provides methods for estimating monthly mean concentrations of selected water-quality constituents that can be used for input to and calibration of the salinity model. Mater-quality data for 32 gaging stations can be used to define selected water-quality characteristics at the 28 model nodes. Materquality data were retrieved from the U.S. Geological Survey's National Mater Data Storage and Retrieval System data base and statistical summaries were prepared. The frequency of water-quality data collection at the gaging stations is inadequate to define monthly mean concentrations of the individual water-quality constituents for all months for the 54-year period; therefore, methods for estimating monthly mean concentrations were developed. Relations between selected water-quality constituents [dissolved solids, hardness (as CaCO 3 ), sodium, sulfate, and chloride] and streamflow were developed as the primary method to estimate monthly mean concentrations. Relations between specific conductance and streamflow and relations between selected water-quality constituents [dissolved solids, hardness (as CaCO 3 ), sodium, sulfate, and chloride] and specific conductance were developed so that a cascaded-regression relation could be developed as a second method of estimating monthly mean concentrations and, thus, utilize a large specific-conductance data base. Information about the quantity and the quality of ground water discharging to the Sheyenne River is needed for model input for reaches of the river where ground water accounts for a substantial part of streamflow during periods of low flow. Ground-water discharge was identified for two reaches of the Sheyenne River. Ground-water discharge to the Sheyenne River in the vicinity of Warwick, N.Dak., was about 14.8 cubic feet per second and the estimated dissolved-solids concentration was about 441 milligrams per liter during October 15 and 16, 1986. Ground-water discharge to the Sheyenne River in a reach between Lisbon and Kindred, N.Dak., ranged from an average of 25.3 cubic feet per second during September 13 to November 19, 1963, to about 45.0 cubic feet per second during October 21 and 22, 1986. Dissolved-solids concentration was estimated at about 442 milligrams per liter during October 21 and 22, 1986.

Water-Resources Investigations Report↗

A river-quality assessment of the upper White River, Indiana

This report attempts to interrelate the physical, chemical, biological, esthetic, and cultural aspects of the upper White River (above Centerton, Ind.) by assessing the mass of available data. Relatively few new data were collected. The White River can be subdivided into five distinct river-quality sections. Section 1, above Winchester, drains a rural area and is affected by agricultural land use, although the river quality generally is good. Section 2, between Winchester and Muncie, is affected by urbanization at Winchester and Muncie. The river quality generally is good, although stretches near the cities occasionally have problems. Section 3, Muncie to Anderson, is polluted by urban effluent. Section 4, Anderson to Indianapolis, is further polluted (particularly at Anderson), but the river tends to recover considerably at Indianapolis, and becomes relatively clean. Section 5, below Indianapolis, is polluted. The river continues to be polluted below the project boundary. The river is affected most severely in the Indianapolis area. For example, in October 1972 the nitrogen load increased from 5.45 tons per day (4.94 tonnes per day) above Indianapolis to 18.43 tons per day (16.72 tonnes per day) below the city. Ten micrograms per kilogram of DDD, 20 micrograms per kilogram of chlordane, and 20 micrograms per kilogram of polychlorinated biphenyls were extracted from the sediments in the White River below Indianapolis. The median coliform bacteria count below Indianapolis is 360,000 colonies per 100 millilitres of water. The only benthic invertebrates found in the White River below Indianapolis are pollution-tolerant species, and very few fish are found. Conditions are similar, but to a somewhat lesser degree, below Muncie.

Indiana↗

Quality of wet deposition in the Grand Calumet River Watershed, northwestern Indiana, October 17, 1995–November 12, 1996

In June 1992, a wet-deposition collection site was established at the Gary (Indiana) Regional Airport to monitor the quantity and chemical quality of wet deposition. During the first phase of sampling, 48 wet-deposition samples were collected between June 30, 1992, and August 31, 1993. A second phase of sampling began in October 1995. During the second phase of sampling, 40 wet-deposition samples were collected between October 17, 1995, and November 12, 1996. This report presents the findings for the second phase of sampling and compares those results to the first phase of sampling. Northwestern Indiana is a heavily industrialized area. Steel production and petroleum refining are two of the area’s predominant industries. High-temperature processes, such as fossil-fuel combustion and steel production, release contaminants to the atmosphere that may result in wet deposition being a major contributor to major-ion and trace-metal loadings in northwestern Indiana and Lake Michigan. Wet-deposition samples collected during the first and second phases of sampling were analyzed for pH, specific conductance, and selected major ions and trace metals. Forty weekly wet-deposition samples were collected at the Gary (Indiana) Regional Airport during the second phase of sampling. Approximately 1.2 times as much wet deposition was collected during the second phase of sampling compared to the first phase. Statistically significant increases (at the 5-percent significance level) in concentrations of potassium, iron, lead, and zinc were determined for samples collected during the second phase of sampling when compared to the first. No statistically significant differences were determined in constituent concentrations between samples collected during warm weather (April 1 through October 31) and during cold weather (November 1 through March 31). Annual loadings for the second phase of sampling were greater than 2 times the loadings determined during the first phase of sampling for silica, iron, potassium, lead, and zinc.

Indiana↗

Cost-effectiveness of the stream-gaging program in Alaska

This report documents the results of a study of the cost-effectiveness of the stream-gaging program in Alaska. Data uses and funding sources were identified for the 110 continuous stream-gaging stations that were being operated in September 1983 with a budget of about $1,700,000 per year. However, for the purposes of the report, only 98 stations were included in the analysis of cost-effectiveness. The current policy for operation of the 98-station program required $1,539,000 (1983 dollars) per year, which results in an average standard error of estimate of streamflow records for open-water periods of 18.4 percent. This overall level of accuracy at the 98 sites could be maintained with a budget of approximately $1,440,000 if the scheduling of visits and allocation of funds to the stations were changed. A minimum budget of $1,381,000 is required to operate the 98 stations; a budget less than this does not permit proper service and maintenance of the gages and recorders. At the minimum budget, the average standard error is 19.8 percent. Several other budgets were analyzed; the maximum budget analyzed was $2,500,000, which resulted in an average standard error of 11.9 percent. A significant portion of the standard error is attributable to loss of gage-height record, which is used to compute open-water discharge records. If gage-height record loss could be prevented, the average standard error could be reduced to 13.4 percent at the minimum operating budget of $1,381,000. It was determined that the standard error of estimate of streamflow records could be reduced by changing some operational policies and by reducing the amount of missing gage-height record. Since there is no method to determine standard errors of Alaska's winter records of streamflow, it was concluded that such a technique should be developed. More than half of western Alaska was identified as having insufficient streamflow data. It is suggested that steps be undertaken to remedy this situation as funds become available.

Alaska↗

Ammonia in ground water from the Mississippi River alluvium, Fort Madison, Iowa

The U.S. Geological Survey, in cooperation with the City of Fort Madison, conducted a study of the potential sources and possible processes that might produce ammonia in ground water from the Mississippi River alluvium near Fort Madison, Iowa. High ammonia concentrations of 3.0 to 6.4 milligrams per liter were detected in water produced from municipal well Fort Madison #4 from 1992 through 1996. Total organic carbon concentrations of about 5 milligrams per liter were also reported during the same time period. Water-level measurements from two municipal wells and one well at Iowa State Penitentiary were used to determine that the general direction of ground-water flow during the two days of sampling was from northeast to southwest toward wells Fort Madison #4 and Fort Madison #5. Continuous pumping of other nearby wells probably influenced the direction of ground-water flow on these days. Because of a till confining unit separating the Mississippi River and the alluvial aquifer, it is uncertain to what extent induced recharge occurs to the alluvial aquifer from the river. Water samples were collected from three municipal wells, two industrial wells, one watersupply well at the Iowa State Penitentiary, one domestic well, two creeks, and the Mississippi River. Tritium analytical results indicate that the time of recharge was after 1953 for water from the municipal wells (where tritium samples were collected). The ammonia concentration, 5.1 milligrams per liter, was considerably higher in ground water collected from well Fort Madison #4 compared to samples collected from other wells. The dissolved organic carbon concentration was also highest in ground water collected from well Fort Madison #4 (5.5 milligrams per liter) although samples from other wells were also relatively high, 2.6 to 5.3 milligrams per liter. The most likely process producing the high ammonia concentration in ground water in the vicinity of well Fort Madison #4 is decomposition of organic matter (ammonification). Nitrogen isotope values, when compared to nitrogen isotope values found in ground water in the vicinity of some of the other wells, indicate the possibility that a higher percentage of the ammonia found in ground water in the vicinity of well Fort Madison #4 may be from human and(or) other animal wastes. Higher concentrations of dissolved phosphorus, orthophosphate, and a higher chloride-to-sodium mole ratio found in ground water sampled from well Fort Madison #4 could be indicative of a sewage or septic source. Potential sources include existing or abandoned septic systems, leaking sanitary sewer lines, commercial or residential waste-disposal sites, and agricultural runoff upgradient from well Fort Madison #4, or possibly, bed sediments of the Mississippi River.

Iowa↗

Discharge ratings for tainter gates and roller gates at Lock and Dam No. 7 on the Mississippi River, La Crescent, Minnesota

The water-surface elevations on the Inland Waterway Navigation System of the upper Mississippi River are controlled during normal operating conditions by various flow controls at 29 locks and dams. The headwater (navigation pool) and tailwater elevations at Lock and Dam No. 7 are controlled by the regulation of 11 tainter gates and 5 roller gates. Discharge ratings for these tainter and roller gates were developed for use in computing discharge through Dam No. 7 and to aid in regulating the navigation pool within its normal operating limits of 639.00 ± 0.20 feet (NGVD 1912). Hydraulic-control variables and discharges were measured at the tainter and roller gates and analyzed for this report. Fifty-two current-meter measurements of discharges that ranged from discharges too low to measure to 12,600 cubic feet per second were made in the forebays of the tainter and roller gates. The measured discharges were used to define flow regimes as a function of static-headwater depth (hi), static-tailwater depth (03), and vertical height of tainter or roller gate opening (hg). Submerged-orifice flow is the predominant flow regime at Lock and Dam No. 7. Twenty-four discharge measurements were used to develop submerged-orifice discharge coefficient relations for the 11 tainter gates. Twenty discharge measurements were used to develop a submerged-orifice discharge coefficient relation for the five roller gates. Coefficients of discharge (Cgs) ranged fron 0.126 (hg = 1 foot) to 1.089 (hg = 10 feet) for tainter gates and from 0.050 (hg = 1 foot) to 0.302 (hg = 14 feet) for roller gates. Disch^ge was measured at three different tainter gates with the gates closed (hg = 0) to evaluate tH tainter-gate leakage-discharge relations. No measurable leakage was observed. The resulting equations can be used to compute discharge at Lock and Dam No. 7 for the tainter and re Her gates under normal flow conditions. Discharge rating tables for the tainter and roller gates are given with a headwater elevation of 639.00 feet normal pool elevation for selected tailwate" elevations and gate openings.

Minnesota↗