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At least 649 records · Page 36Linked to original sources
USGS1963

Dissolved-mineral inflow to Great Salt Lake and chemical characteristics of the salt lake brine. Part I: Selected hydrologic data

This report presents the data collected for a study of the dissolved-mineral load contributed by surficial sources to Great Salt Lake, Utah. The study was conducted by the U.S. Geological Survey in cooperation with the University of Utah during the period from July 1959 through June 1962, and is part of an overall investigation of the Great Salt Lake basin by the University. Financial support for the study was provided by the U.S. Geological Survey and by the University of Utah Research Fund and Uniform School Fund. Some of the data presented in this report were obtained as part of cooperative programs between the Geological Survey and other agencies.

Utah↗
USGS2003

Survival, transport, and sources of fecal bacteria in streams and survival in land-applied poultry litter in the upper Shoal Creek basin, southwestern Missouri, 2001–2002

Densities of fecal coliform bacteria along a 5.7-mi (mile) reach of Shoal Creek extending upstream from State Highway 97 (site 3) to State Highway W (site 2) and in two tributaries along this reach exceeded the Missouri Department of Natural Resources (MDNR) standard of 200 col/100 mL (colonies per 100 milliliters) for whole-body contact recreation. A combination of techniques was used in this report to provide information on the source, transport, and survival of fecal bacteria along this reach of Shoal Creek. Results of water-quality samples collected during dye-trace and seepage studies indicated that at summer low base-flow conditions, pastured cattle likely were a substantial source of fecal bacteria in Shoal Creek at the MDNR monitoring site (site 3) at State Highway 97. Using repeat element Polymerase Chain Reaction (rep-PCR), cattle were the presumptive source of about 50 percent of the Escherichia coli ( E. coli ) isolates in water samples from site 3. Cattle, horses, and humans were the most common presumptive source of E. coli isolates at sites further upstream. Poultry was identified by rep-PCR as a major source of E. coli in Pogue Creek, a tributary in the upper part of the study area. Results of the rep-PCR were in general agreement with the detection and distribution of trace concentrations of organic compounds commonly associated with human wastewater, such as caffeine, the antimicrobial agent triclosan, and the pharmaceutical compounds acetaminophen and thiabendazole (a common cattle anthelmintic). Significant inputs of fecal bacteria to Shoal Creek occurred along a 1.6-mi reach of Shoal Creek immediately upstream from site 3. During a 36-hour period in July 2001, average densities of fecal coliform and E. coli bacteria increased from less than or equal to 500 col/100 mL upstream from this stream reach (sample site 2c) to 2,100 and 1,400 col/100 mL, respectively, at the MDNR sampling site. Fecal bacteria densities exhibited diurnal variability at all five sampling sites along the 5.7-mi study reach of Shoal Creek, but the trends at successive downstream sites were out of phase and could not be explained by simple advection and dispersion. At base-flow conditions, the travel time of bacteria in Shoal Creek along the 5.7-mi reach between State Highway W (site 2) and the MDNR sampling site (site 3) was about 26 hours. Substantial dispersion and dilution occurs along the upper 4.1 mi of this reach because of inflows from a number of springs and tributaries and the presence of several long pools and channel meanders. Minimal dispersion and dilution occurs along the 1.6-mi reach immediately upstream from the MDNR sampling site. Measurements of fecal bacteria decay in Shoal Creek during July 2001 indicated that about 8 percent of fecal coliform and E. coli bacteria decay each hour with an average first-order decay constant of 0.084 h -1 (per hour). Results of field test plots indicated that substantial numbers of fecal bacteria present in poul try litter can survive in fields for as much as 8 weeks after the application of the litter to the land surface. Median densities of fecal coliform and E. coli in slurry-water samples collected from fields increased from less than 60 col/100 mL before the application of turkey and broiler litter, to as large as 420,000 and 290,000 col/100 mL after the application of litter. Bacteria densities in the test plots generally decreased in a exponential manner over time with decay rates ranging from 0.085 to 0.185 d -1 (per day) for fecal coliform to between 0.100 and 0.250 d -1 for E. coli . The apparent survival of significant numbers of fecal bacteria on fields where poultry litter has been applied indicates that runoff from these fields is a potential source of fecal bacteria to vicinity streams for many weeks following litter application.

Water-Resources Investigations Report↗
USGS1986

Hydrogeology and ground-water quality of Lannon-Sussex area, northeastern Waukesha County, Wisconsin

The Silurian dolomite aquifer in the Lannon-Sussex area of southeastern Wisconsin is overlain by glacial deposits, but is within 8 ft of the land surface over 15% of the study area. The proximity of the dolomite aquifer to the land surface makes it susceptible to contamination from man 's activities. Water from the aquifer was analyzed and several characteristics were monitored in a 30-sq-mi area of Waukesha County, including: water temperature, calcium, magnesium, potassium, strontium, alkalinity, chlorides, fluorides, sulfates, nitrites, nitrates, nitrogen, iron, manganese, hardness, and pH. The water is hard, commonly having a hardness of more than 350 mg/L as CaCO 3 , and high in iron, commonly containing more than 0.3 mg/L. However, nutrient concentrations are not high; nitrogen, greater than 8 mg/L; phosphorus, none detected; and potassium, greater than 4 mg/L. The chloride content of the water averages more than 50 mg/L indicating contamination probably from septic systems. The water quality varies over a time. High concentrations of chloride and, occasionally, of bacteria correlate with periods of groundwater recharge over a period of 17 months. Chloride concentrations were highest in water from wells where housing density is high. An attempt was made to relate water quality changes with depth to beds of cherty dolomite that are identified in geologic logs; it was postulated that these zones might be confining beds. Although the beds appear to extend over the area, no evidence was found that they are confining beds, other than reports of a few artesian wells. Water quality, indicated by chloride content, showed no significant relation to well bottom altitudes, casing bottom altitude, or well depth.

Wisconsin↗
USGS1996

Low-flow characteristics at selected sites on streams in southern and western Puerto Rico

Knowledge of the magnitude and frequency of low flows is important for the optimal development of surface-water resources in Puerto Rico. This report presents analyses of low-flow data for 9 continuous-record gaging stations and 105 partial-record stations in southern and western Puerto Rico. The report includes analyses of lowflow data and tabulations of computed low-flow magnitude and frequency characteristics for 7-, 14-, 30-, 60-, and 90-consecutive days with recurrence intervals of 2 and 10 years for continuous-record gaging stations based on the log-Pearson Type III frequency distribution or graphically adjusted logPearson frequency curves. Estimates of low-flow characteristics are provided for partial-record stations for 7-, 14-, and 30-consecutive days with recurrence intervals of 2 and 10 years. Low-flow characteristics at partial-record stations were estimated based on the relation of base-flow discharge measurements at the partial-record stations and concurrent discharges at nearby continuous-record stations.

Water-Resources Investigations Report↗
USGS2000

Water quality in alluvial aquifers of the southern Rocky Mountains Physiographic Province, upper Colorado River basin, Colorado, 1997

Water-quality samples were collected in the summer of 1997 from 45 sites (43 wells and 2 springs) in selected alluvial aquifers throughout the Southern Rocky Mountains physiographic province of the Upper Colorado River Basin study unit as part of the U.S. Geological Survey National Water-Quality Assessment Program. The objective of this study was to assess the water-quality conditions in selected alluvial aquifers in the Southern Rocky Mountains physiographic province. Alluvial aquifers are productive aquifers in the Southern Rocky Mountains physiographic province and provide for easily developed wells. Water-quality samples were collected from areas where ground water is used predominantly for domestic or public water supply. Twenty-three of the 45 sites sampled were located in or near mining districts. No statistical differences were observed between the mining sites and sites not associated with mining activities for the majority of the constituents analyzed. Water samples were analyzed for major ions, nutrients, dissolved organic carbon, trace elements, radon-222, pesticides, volatile organic compounds, bacteria, and methylene blue active substances. In addition, field parameters consisting of water temperature, specific conductance, dissolved oxygen, pH, turbidity, and alkalinity were measured at all sites. Specific conductance for the ground-water sites ranged from 57 to 6,650 microsiemens per centimeter and had higher concentrations measured in areas such as the northwestern part of the study unit. Dissolved oxygen ranged from 0.1 to 6.0 mg/L (milligrams per liter) and had a median concentration of 2.9 mg/L. The pH field values ranged from 6.1 to 8.1; about 4 percent of the sites (2 of 45) had pH values outside the range of 6.5 to 8.5 and so did not meet the U.S. Environmental Protection Agency secondary maximum contaminant level standard for drinking water. About 5 percent (2 of 43) of the samples exceeded the U.S. Environmental Protection Agency recommended turbidity value of 5 nephelometric turbidity units; one of these samples was from a monitoring well. The U.S. Environmental Protection Agency secondary maximum contaminant levels for dissolved solids, sulfate, iron, and manganese were exceeded at some of the sites. Higher dissolved-solids concentrations were detected where sedimentary rocks are exposed, such as in the northwestern part of the Southern Rocky Mountains physiographic province. The dominant water compositions for the sites sampled are calcium, magnesium, and bicarbonate. However, sites in areas where sedimentary rocks are exposed and sites located in or near mining areas show more sulfate-dominated waters. Nutrient concentrations were less than the U.S. Environmental Protection Agency drinking-water standards. Only one site had a nitrate concentration greater than 3.0 mg/L, a level indicating possible influence from human activities. No significant differences among land-use/land-cover classifications (forest, rangeland, and urban) for drinking-water wells (42 sites) were identified for dissolved-solids, sulfate, nitrate, iron or manganese concentrations. Radon concentrations were higher in parts of the study unit where Precambrian rocks are exposed. All radon concentrations in ground water exceeded the previous U.S. Environmental Protection Agency proposed maximum contaminant level for drinking water, which has been withdrawn pending further review. Pesticide detections were at concentrations below the reporting limits and were too few to allow for comparison of the data. Eight volatile organic compounds were detected at six sites; all concentrations complied with U.S. Environmental Protection Agency drinking-water standards. Total coliform bacteria were detected at six sites, but no Escherichia coli ( E. coli ) was detected. Methylene blue active substances were detected at three sites at concentrations just above the reporting limit. Overall, the water quality in the Southern Rocky Mountains physiographic province is suitable for most uses, but natural and human factors affect the water quality.

Colorado↗
USGS2003

Development and calibration of a ground-water flow model for the Sparta Aquifer of southeastern Arkansas and north-central Louisiana and simulated response to withdrawals, 1998-2027

The Sparta aquifer, which consists of the Sparta Sand, in southeastern Arkansas and north-central Louisiana is a major water resource and provides water for municipal, industrial, and agricultural uses. In recent years, the demand in some areas has resulted in withdrawals from the Sparta aquifer that substantially exceed replenishment of the aquifer. Considerable drawdown has occurred in the potentiometric surface forming regional cones of depression as water is removed from storage by withdrawals. These cones of depression are centered beneath the Grand Prairie area and the cities of Pine Bluff and El Dorado in Arkansas, and Monroe in Louisiana. The rate of decline for hydraulic heads in the aquifer has been greater than 1 foot per year for more than a decade in much of southern Arkansas and northern Louisiana where hydraulic heads are now below the top of the Sparta Sand. Continued hydraulic-head declines have caused water users and managers alike to question the ability of the aquifer to supply water for the long term. Concern over protecting the Sparta aquifer as a sustainable resource has resulted in a continued, cooperative effort by the Arkansas Soil and Water Conservation Commission, U.S. Army Corps of Engineers, and the U.S. Geological Survey to develop, maintain, and utilize numerical ground-water flow models to manage and further analyze the ground-water system. The work presented in this report describes the development and calibration of a ground-water flow model representing the Sparta aquifer to simulate observed hydraulic heads, documents major differences in the current Sparta model compared to the previous Sparta model calibrated in the mid-1980's, and presents the results of three hypothetical future withdrawal scenarios. The current Sparta model-a regional scale, three-dimensional numerical ground-water flow model-was constructed and calibrated using available hydrogeologic, hydraulic, and water-use data from 1898 to 1997. Significant changes from the previous model include grid rediscretization of the aquifer, extension of the active model area northward beyond the Cane River Formation facies change, and representation of model boundaries. The current model was calibrated with the aid of parameter estimation, a nonlinear regression technique, combined with trial and error parameter adjustment using a total of 795 observations from 316 wells over 4 different years-1970, 1985, 1990, and 1997. The calibration data set provides broad spatial and temporal coverage of aquifer conditions. Analysis of the residual statistics, spatial distribution of residuals, simulated compared to observed hydrographs, and simulated compared to observed potentiometric surfaces were used to analyze the ability of the calibrated model to simulate aquifer conditions within acceptable error. The calibrated model has a root mean square error of 18 feet for all observations, an improvement of more than 12 feet from the previous model. The current Sparta model was used to predict the effects of three hypothetical withdrawal scenarios on hydraulic heads over the period 1998-2027 with one of those extended indefinitely until equilibrium conditions were attained, or steady state. In scenario 1a, withdrawals representing the time period from 1990 to 1997 was held constant for 30 years from 1998 to 2027. Hydraulic heads in the middle of the cone of depression centered on El Dorado decreased by 10 feet from the 1997 simulation to 222 feet below NGVD of 1929 in 2027. Hydraulic heads in the Pine Bluff cone of depression showed a greater decline from 61 feet below NGVD of 1929 to 78 feet below NGVD of 1929 in the center of the cone. With these same withdrawals extended to steady state (scenario 1b), hydraulic heads in the Pine Bluff cone of depression center declined an 2 Development and Calibration of a Ground-Water Flow Model for the Sparta Aquifer of Southeastern Arkansas and North-Central Louisiana and Simulated Response to Withdrawa

Water-Resources Investigations Report↗
USGS2003

Metal interferences and their removal prior to the determination of As(T) and As(III) in acid mine waters by hydride generation atomic absorption spectrometry

Hydride generation atomic absorption spectrometry (HGAAS) is a sensitive and selective method for the determination of total arsenic (arsenic(III) plus arsenic(V)) and arsenic(III); however, it is subject to metal interferences for acid mine waters. Sodium borohydride is used to produce arsine gas, but high metal concentrations can suppress arsine production. This report investigates interferences of sixteen metal species including aluminum, antimony(III), antimony(V), cadmium, chromium(III), chromium(IV), cobalt, copper(II), iron(III), iron(II), lead, manganese, nickel, selenium(IV), selenium(VI), and zinc ranging in concentration from 0 to 1,000 milligrams per liter and offers a method for removing interfering metal cations with cation exchange resin. The degree of interference for each metal without cation-exchange on the determination of total arsenic and arsenic(III) was evaluated by spiking synthetic samples containing arsenic(III) and arsenic(V) with the potential interfering metal. Total arsenic recoveries ranged from 92 to 102 percent for all metals tested except antimony(III) and antimony(V) which suppressed arsine formation when the antimony(III)/total arsenic molar ratio exceeded 4 or the antimony(V)/total arsenic molar ratio exceeded 2. Arsenic(III) recoveries for samples spiked with aluminum, chromium(III), cobalt, iron(II), lead, manganese, nickel, selenium(VI), and zinc ranged from 84 to 107 percent over the entire concentration range tested. Low arsenic(III) recoveries occurred when the molar ratios of metals to arsenic(III) were copper greater than 120, iron(III) greater than 70, chromium(VI) greater than 2, cadmium greater than 800, antimony(III) greater than 3, antimony(V) greater than 12, or selenium(IV) greater than 1. Low recoveries result when interfering metals compete for available sodium borohydride, causing incomplete arsine production, or when the interfering metal oxidizes arsenic(III). Separation of interfering metal cations using cation-exchange prior to hydridegeneration permits accurate arsenic(III) determinations in acid mine waters containing high concentrations of interfering metals. Stabilization of the arsenic redox species for as many as 15 months is demonstrated for samples that have been properly filtered and acidified with HCl in the field. The detection limits for the method described in this report are 0.1 micrograms per liter for total arsenic and 0.8 micrograms per liter for arsenic(III).

Water-Resources Investigations Report↗
USGS1973

Index of time-of-travel studies of the US Geological Survey

This index identifies locations on streams where the U. S. Geological Survey has investigated the time of travel of a highly soluble material moving through a reach of stream channel. This index provides information only on the location of studied stream reaches; it contains no basic data. It does contain, however, a list of references to published data and analytical reports on time of travel and a list of U.S. Geological Survey offices where basic time-of-travel data are on file.

Water-Resources Investigations Report↗
USGS1997

Bathymetric surveys of Morse and Geist Reservoirs in central Indiana made with acoustic Doppler current profiler and global positioning system technology, 1996

Acoustic Doppler current profiler, global positioning system, and geographic information system technology were used to map the bathymetry of Morse and Geist Reservoirs, two artificial lakes used for public water supply in central Indiana. The project was a pilot study to evaluate the use of the technologies for bathymetric surveys. Bathymetric surveys were last conducted in 1978 on Morse Reservoir and in 1980 on Geist Reservoir; those surveys were done with conventional methods using networks of fathometer transects. The 1996 bathymetric surveys produced updated estimates of reservoir volumes that will serve as base-line data for future estimates of storage capacity and sedimentation rates.An acoustic Doppler current profiler and global positioning system receiver were used to collect water-depth and position data from April 1996 through October 1996. All water-depth and position data were imported to a geographic information system to create a data base. The geographic information system then was used to generate water-depth contour maps and to compute the volumes for each reservoir.The computed volume of Morse Reservoir was 22,820 acre-feet (7.44 billion gallons), with a surface area of 1,484 acres. The computed volume of Geist Reservoir was 19,280 acre-feet (6.29 billion gallons), with a surface area of 1,848 acres. The computed 1996 reservoir volumes are less than the design volumes and indicate that sedimentation has occurred in both reservoirs. Cross sections were constructed from the computer-generated surfaces for 1996 and compared to the fathometer profiles from the 1978 and 1980 surveys; analysis of these cross sections also indicates that some sedimentation has occurred in both reservoirs.The acoustic Doppler current profiler, global positioning system, and geographic information system technologies described in this report produced bathymetric maps and volume estimates more efficiently and with comparable or greater resolution than conventional bathymetry methods.

Water-Resources Investigations Report↗
USGS1997

Environmental setting and implications for water quality in the Western Lake Michigan Drainages

In 1991, the U.S. Geological Survey began to implement its National Water-Quality Assessment (NAWQA) program. The Western Lake Michigan Drainages was one of 20 study units selected for investigation to begin in 1991. The study-unit investigation will include an assessment of surface- and ground-water quality. The quality of water in a study unit is intrinsically related to the natural and anthropogenic features of the study unit. The natural features include geology, weather and climate, vegetation, and hydrology. The anthropogenic features of the basin include population distribution, land use and land cover, agricultural practices, and water use. This report describes the natural and anthropogenic features that constitute the environmental setting of the Western Lake Michigan Drainages as well as the implications of those features on the water quality.

Wisconsin↗
USGS1995

Relation of fracture orientation to linear terrain features, anisotropic transmissivity, and seepage to streams in the karst Prairie du Chien Group, southeastern Minnesota

Ground-water flow in the karst-terrane aquifers of southeastern Minnesota is not well defined. Variable fracture patterns in the bedrock affect permeability. Techniques to predict the effects of fracture patterns on ground-water flow in the karst-terrane aquifers of southeastern Minnesota are unavailable. The use of such techniques may be useful to officials responsible for the management and protection of ground water in these aquifers, which have a high susceptibility to contamination. The U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources and the Legislative Commission on Minnesota Resources, investigated fracture patterns, anisotropic transmissivity, and seepage to streams from the Prairie du Chien Group, which is the karst portion of the St. Peter-Prairie du Chien-Jordan aquifer, to improve the understanding of ground-water flow through karst-terrane aquifers in southeastern Minnesota. This report presents the results of testing hypotheses that (1) the major axes of linear terrain features correlate with the major axes of subsurface fractures in the Prairie du Chien Group, and that (2) the major axes of subsurface fractures in the Prairie du Chien Group correlate with seepage from the Prairie du Chien Group. The first hypothesis was tested by comparison of linear terrain features to fracture orientation measurements. Fracture orientations in 10 exposures of the Prairie du Chien Group at quarries, road cuts, and natural outcrops showed statistically significant directional trends at 8 of 10 sites. Directional trends of linear terrain features identified from 1:80,000 aerial photographs were significant in four of the ten 60-square mile areas that surround these sites. The fracture orientation measurements correlate with the local linear terrain features in 2 of the 10 sites. The second hypothesis was tested by analyzing the correlation between seepage rates into streams hydraulically connected to the Prairie du Chien Group and surrounding linear terrain features that were mapped in approximately 300 square mile areas. Data from Riceford Creek support this hypothesis; data from Crow Creek and Middle Fork of the Whitewater River and from Duschee Creek are inconclusive. This hypothesis could not be tested by the data from the Middle Fork of the Zumbro River, the South Branch of the Root River, and the South Branch of the Middle Fork of the Zumbro River because the surrounding linear terrain features lack directional trends. The transmissivity of the karst portion of the St. Peter-Prairie du Chien-Jordan aquifer is anisotropic at an aquifertest site in the study area. Results of the aquifer test indicate that the major axis of transmissivity is along a line N95°E. The aquifer-test results indicate that the principal axis of joint fractures at the test site is slightly clockwise from an east-west line because this axis is assumed to correlate with the major axis of horizontal transmissivity.

Minnesota↗
USGS1998

Quality-Assurance/Quality-Control Manual for Collection and Analysis of Water-Quality Data in the Ohio District, US Geological Survey

The U.S. Geological Survey (USGS), Water Resources Division (WRD), requires that quality-assurance/quality-control (QA/QC) activities be included in any sampling and analysis program. Operational QA/QC procedures address local needs while incorporating national policies. Therefore, specific technical policies were established for all activities associated with water-quality project being done by the Ohio District. The policies described in this report provide Ohio District personnel, cooperating agencies, and others with a reference manual on QA/QC procedures that are followed in collecitng and analyzing water-quality samples and reporting water-quality information in the Ohio District. The project chief, project support staff, District Water-Quality Specialist, and District Laboratory Coordinator are all involved in planning and implementing QA/QC activities at the district level. The District Chief and other district-level managers provide oversight, and the Regional Water-Quality Specialist, Office of Water Quality (USGS headquarters), and the Branch of Quality Systems within the Office of Water Quality create national QA/QC polices and provide assistance to District personnel. In the literature, the quality of all measurement data is expressed in terms of precision, variability, bias, accuracy, completeness, representativeness, and comparability. In the Ohio District, bias and variability will be used to describe quality-control data generated from samples in the field and laboratory. Each project chief must plan for implementation and financing of QA/QC activities necessary to achieve data-quality objectives. At least 15 percent of the total project effort must be directed toward QA/QC activities. Of this total, 5-10 percent will be used for collection and analysis of quality-control samples. This is an absolute minimum, and more may be required based on project objectives. Proper techniques must be followed in the collection and processing of surface-water, ground-water, biological, precipitation, bed-sediment, bedload, suspended-sediment, and solid-phase samples. These techniques are briefly described in this report and are extensively documented. The reference documents listed in this report will be kept by the District librarian and District Water-Quality Specialist and updated regularly so that they are available to all District staff. Proper handling and documentation before, during, and after field activities are essential to ensure the integrity of the sample and to correct erroneous reporting of data results. Field sites are to be properly identified and entered into the data base before field data-collection activities begin. During field activities, field notes are to be completed and sample bottles appropriately labeled a nd stored. After field activities, all paperwork is to be completed promptly and samples transferred to the laboratory within allowable holding times. All equipment used by District personnel for the collection and processing of water-quality samples is to be properly operated, maintained, and calibrated by project personnel. This includes equipment for onsite measurement of water-quality characteristics (temperature, specific conductance, pH, dissolved oxygen, alkalinity, acidity, and turbidity) and equipment and instruments used for biological sampling. The District Water-Quality Specialist and District Laboratory Coordinator are responsible for preventive maintenance and calibration of equipment in the Ohio District laboratory. The USGS National Water Quality Laboratory in Arvada, Colo., is the primary source of analytical services for most project work done by the Ohio District. Analyses done at the Ohio District laboratory are usually those that must be completed within a few hours of sample collection. Contract laboratories or other USGS laboratories are sometimes used instead of the NWQL or the Ohio District laboratory. When a contract laboratory is used, the projec

Water-Resources Investigations Report↗
USGS1999

Comparison of two approaches for determining ground-water discharge and pumpage in the lower Arkansas River Basin, Colorado, 1997-98

In March 1994, the Colorado Division of Water Resources (CDWR) adopted “Rules Governing the Measurement of Tributary Ground Water Diversions Located in the Arkansas River Basin” (Office of the State Engineer, 1994); these initial rules were amended in February 1996 (Office of the State Engineer, 1996). The amended rules require users of wells that divert tributary ground water to annually report the water pumped monthly by each well. The rules allow a well owner to report the pumpage measured by a totalizing flowmeter (TFM) or pumpage determined from electrical power data and a power conversion coefficient (PCC) (Hurr and Litke, 1989). Opinions by representatives of the State of Kansas, presented before the Special Master hearing a court case [State of Kansas v. State of Colorado, No. 105 Original (1996)] concerning post-Compact well pumping, stated that the PCC approach does not provide the same level of accuracy and reliability as a TFM when used to determine pumpage. In 1997, the U.S. Geological Survey (USGS), in cooperation with the CDWR, began a 2-year study to compare ground-water pumpage estimates made using the TFM and the PCC approaches. The study area was along the Arkansas River between Pueblo, Colorado, and the Colorado-Kansas State line (fig. 1). The two approaches for estimating ground-water discharge and pumpage were compared for more than 100 wells completed in the alluvial aquifer of the Arkansas River Basin. The TFM approach uses an inline flowmeter to directly measure instantaneous discharge and the total volume of water pumped at a well. The PCC approach uses electrical power consumption records and a power conversion coefficient to estimate the pumpage at ground-water wells. This executive summary describes the results of the comparison of the two approaches. Specifically, (1) the differences in instantaneous discharge measured with three portable flowmeters and measured with an inline TFM are evaluated, and the statistical differences in paired instantaneous discharge between the two approaches are determined; (2) short- and long-term variations in the PCC’s are presented; (3) differences in pumpage between the two approaches are evaluated, and the statistical differences in pumpage between the two approaches are determined; (4) potential sources of discrepancy between pumpage estimates are discussed; and (5) differences in total network pumpage using the two approaches are presented. During the irrigation seasons of 1997 and 1998, instantaneous discharge and electrical power demand were measured at randomly selected wells to determine PCC’s. At more than 100 wells, the PCC’s determined during the 1998 season were applied to total electrical power consumption data that was recorded between the initial and final readings at each network well site in 1998 to estimate total ground-water pumpage. At each site, an inline TFM was installed in a full-flowing, acceptable test section of pipe on the discharge side of the pump where the measurement of discharge was made. Measurements of instantaneous ground-water discharge also were made using three different types of portable flowmeters. The average velocity multiplied by the cross-sectional area of the discharge pipe was used to compute the discharge in gallons per minute. Whenever possible, discharge measurements were made at each network site using all three types of portable flowmeters.

Colorado↗
USGS2003

Anthropogenic constituents in shallow ground water in the Upper Illinois River Basin

The potential for anthropogenic effects on ground water is becoming of increasing concern as land throughout the Nation becomes more urbanized. The possible contamination of water resources by volatile organic compounds (VOCs), pesticides (including transformation products), and nitrate, from current urban land use and past agricultural land use, is of particular concern. As part of the U.S. Geological Survey's National Water-Quality Assessment program, water samples for analysis of VOCs, pesticides, and nitrate were collected from 43 wells in shallow (175 feet deep or less) ground water in glacial deposits overlying a major bedrock aquifer in recently urbanized areas in the Chicago, Ill. and Milwaukee, Wis. metropolitan counties.Constituents were reported using two reporting levels. For the laboratory reporting level, the risk of a false positive or false negative detection is less than or equal to 1 percent. For the information-rich method level, estimated concentrations are identified positively and are qualified to be present on the basis of quality-control criteria, but have a higher risk of false positive detections.VOCs were detected in 32 percent (12 of 38) of the well samples with 15 detections of 7 VOCs, based on laboratory reporting levels. Concentrations ranged from 0.03 (estimated) to 4.6 micrograms per liter (?g/L), with a median concentration of 0.13 ?g/L. Methyl tert-butyl ether (MTBE) and trichloromethane (chloroform) were the most common with detections in 10 percent (4 of 38) of the well samples. Using information-rich method reporting levels, VOCs were detected in 74 percent of the wells with 37 detections of 15 VOCs. Chloroform was most common with detections in 24 percent (9 of 38) of the well samples.Pesticides were detected in 62 percent (26 of 42) of the well samples with 83 detections of 20 pesticides, based on laboratory reporting levels for the respective constituent. Concentrations ranged from 0.003 (estimated) to 3.6 (estimated) ?g/L, with a median concentration of 0.06 ?g/L. Deethylatrazine was most common with detections in 43 percent (18 of 42) of the well samples. Using information-rich method reporting levels, pesticides were detected in 74 percent (31 of 42) of the well samples with 134 detections of 29 pesticides. Deethylatrazine was most common with detections in 45 percent (19 of 42) of the well samples.Nitrate concentrations ranged from less than 0.047 to 12.5 milligrams per liter (mg/L) with a median concentration of 0.068 mg/L. Nitrate concentrations were greater than 2 mg/L in 30 percent (13 of 43) of the wells sampled. Total VOC detections did not correlate well (less than Spearman Rank correlation value of plus or minus 0.10) with well depth, age, or dissolved oxygen. Total pesticide detections did correlate with dissolved oxygen and negatively correlated with well depth. Nitrate concentrations correlated with dissolved oxygen and apparent recharge date.No VOC or pesticide concentrations exceeded U.S. Environmental Protection Agency drinking-water standards and only one nitrate 2 Anthropogenic Constituents in Shallow Ground Water in the Upper Illinois River Basin detection exceeded the standards. However, of the 43 wells sampled for VOCs or pesticides using information-rich methods, or nitrate at laboratory reporting levels, 40 of 43 (93 percent) well samples had at least one detection of a VOC or pesticide, or a detection of nitrate above 2.0 mg/L. This result indicates that most of these wells are anthropogenically affected, but presently not at U.S. Environmental Protection Agency drinking-water regulation levels of concern. The wells sampled were not public drinking-water supplies; therefore, these wells were not subject to U.S. Environmental Protection Agency drinking-water regulations.

Water-Resources Investigations Report↗
USGS2011

Numerical simulation of groundwater flow for the Yakima River basin aquifer system, Washington

A regional, three-dimensional, transient numerical model of groundwater flow was constructed for the Yakima River basin aquifer system to better understand the groundwater-flow system and its relation to surface-water resources. The model described in this report can be used as a tool by water-management agencies and other stakeholders to quantitatively evaluate proposed alternative management strategies that consider the interrelation between groundwater availability and surface-water resources. The model was constructed using the U.S. Geological Survey finite-difference model MODFLOW. The model uses 1,000-foot grid cells that subdivide the model domain by 600 rows and 600 columns. Forty-eight hydrogeologic units in the model are included in 24 model layers. The Yakima River, all major tributaries, and major agricultural drains are included in the model as either drain cells or streamflow-routing cells. Recharge was estimated from previous work using physical process models. Groundwater pumpage specified in the model is derived from monthly pumpage values previously estimated from another component of this study. The pumpage values include estimates for wells with standby/reserve rights that are used in drought years. The model was calibrated to the transient conditions for October 1959 to September 2001. Calibration was completed by using traditional trial-and-error methods and automated parameter-estimation techniques. The model simulates the shape and slope of the water table that generally is consistent with mapped water levels. At well observation points, the average difference between simulated and measured hydraulic heads is -49 feet with a root-mean-square error divided by the total difference in water levels of 4 percent. Simulated river streamflow was compared to measured streamflow at seven sites. Annual differences between measured and simulated streamflow for the sites ranged from 1 to 9 percent. Calibrated model output includes a 42-year estimate of a monthly water budget for the aquifer system. Five applications (scenarios) of the model were completed to obtain a better understanding of the relation between pumpage and surface-water resources and groundwater levels. For the first three scenarios, the calibrated transient model was used to simulate conditions without: (1) pumpage from all hydrogeologic units, (2) pumpage from basalt hydrogeologic units, and (3) exempt-well pumpage. The simulation results indicated potential streamflow capture by the existing pumpage from 1960 through 2001. The quantity of streamflow capture generally was inversely related to the total quantity of pumpage eliminated in the model scenarios. For the fourth scenario, the model simulated 1994 through 2001 under existing conditions with additional pumpage estimated for pending groundwater applications. The differences between the calibrated model streamflow and this scenario indicated additional decreases in streamflow of 91 cubic feet per second in the model domain. Existing conditions representing 1994 through 2001 were projected through 2025 for the fifth scenario and indicated additional streamflow decreases of 38 cubic feet per second and groundwater-level declines.

Scientific Investigations Report↗
USGS1978

Plan of study for the High Plains regional aquifer-system analysis in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

The Ogallala Formation and associated Tertiary and Quarternary deposits form the principal aquifers supporting irrigation in the High Plains of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. The volume of water in storage within the aquifers is declining in most of the High Plains because water is being withdrawn in excess of the rate of replenishment. The U.S. Geological Survey has initiated a 5-year study of the High Plains aquifer system to develop the geohydrologic data base and computer models of the ground-water flow system needed to evaluate the response of the aquifer,system to ground-water management alternatives. This report describes the objectives, plan, and organization of the study and outlines the work to be accomplished in each state in the study area.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS1983

Initial assessment of time of travel and mixing through Gulf Island Pond and the lower Androscoggin River, Maine

Flow-stratification patterns were observed in Gulf Island Pond during time-of-travel studies in May and August 1980. The stratification patterns in this 70 million cubic-meter impoundment were due to a temperature differences between inflowing water and reservoir water. Separation was observed at temperature differences of 0.5 degrees C in May 1980 and 1.0 degrees C in August 1980. The pathway taken by inflowing water through the reservoir was governed by the temperature-related density forces acting between the two water masses. Data collected during August 1980 to define differences in dye concentrations with depth at two fixed profile points in Gulf Island Pond showed average water velocity to be seven times faster near the bottom than near the surface. A concept of mass flow was used to analyze data collected at sites downstream from Gulf Island Dam where flow varied rapidly with time. This report presents the mathematical derivation of controid traveltime, skewness, and percentage recovery of dye mass as determined from mass versus time curves. (USGS)

Water-Resources Investigations Report↗
USGS1985

Effects of sanitary sewers on ground-water levels and streams in Nassau and Suffolk Counties, New York; part 2: Development and application of southwest Suffolk County model

By 1990, sanitary sewers in Nassau County Sewage Disposal Districts 2 and 3 and Suffolk County Southwest Sewer District will discharge to the ocean 140 cu ft of water/sec that would otherwise be returned to the groundwater system through septic tanks and similar systems. To evaluate the effects of this loss on groundwater levels and streamflow, the U.S. Geological Survey developed a groundwater flow model that couples a fine-scale subregional model to a regional model of larger scale. The regional model generates flux boundary conditions for the subregional model, and the subregional model provides detail in the area of concern. Results indicate that the water table will decline by as much as 8 ft along the Suffolk-Nassau county line, with effects decreasing eastward. Base flow is predicted to decrease by as much as 73% in a stream along the county line, but this effect will decrease to zero just east of the sewered area. This report is one of a series describing the predicted hydrologic effects of sewers in southern Nassau and southwest Suffolk Counties. (USGS)

New York↗