Search USGS⌕ Search

SEARCH · Search USGS

Results for “Scientific Investigations Report”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,585 records · Page 88Linked to original sources

Lithologic and physicochemical properties and hydraulics of flow in and near the freshwater/saline-water transition zone, San Antonio segment of the Edwards aquifer, south-central Texas, based on water-level and borehole geophysical log data, 1999-2007

The freshwater zone of the San Antonio segment of the Edwards aquifer in south-central Texas (hereinafter, the Edwards aquifer) is bounded to the south and southeast by a zone of transition from freshwater to saline water (hereinafter, the transition zone). The boundary between the two zones is the freshwater/saline-water interface (hereinafter, the interface), defined as the 1,000-milligrams per liter dissolved solids concentration threshold. This report presents the findings of a study, done by the U.S. Geological Survey in cooperation with the San Antonio Water System, to obtain lithologic properties (rock properties associated with known stratigraphic units) and physicochemical properties (fluid conductivity and temperature) and to analyze the hydraulics of flow in and near the transition zone of the Edwards aquifer on the basis of water-level and borehole geophysical log data collected from 15 monitoring wells in four transects during 1999-2007. No identifiable relation between conductivity values from geophysical logs in monitoring wells in all transects and equivalent freshwater heads in the wells at the times the logs were run is evident; and no identifiable relation between conductivity values and vertical flow in the boreholes concurrent with the times the logs were run is evident. The direction of the lateral equivalent freshwater head gradient and thus the potential lateral flow at the interface in the vicinity of the East Uvalde transect fluctuates between into and out of the freshwater zone, depending on recharge and withdrawals. Whether the prevailing direction on average is into or out of the freshwater zone is not clearly indicated. Equivalent freshwater head data do not indicate a prevailing direction of the lateral gradient at the interface in the vicinity of the Tri-County transect. The prevailing direction on average of the lateral gradient and thus potential lateral flow at the interface in the vicinity of the Kyle transect likely is from the transition zone into the freshwater zone. The hypothesis regarding the vertical gradient at the East Uvalde transect, and thus the potential for vertical flow near an interface conceptualized as a surface sloping upward in the direction of the dip of the stratigraphic units, is that the potential for vertical flow fluctuates between into and out of the freshwater zone, depending on recharge and withdrawals. At the Tri-County transect, a downward gradient on the fresh-water side of the interface and an upward gradient on the saline-water side are evidence of opposing potentials that appear to have stabilized the position of the interface over the range of hydrologic conditions that occurred at the times the logs were run. At the Fish Hatchery transect, an upward gradient on the saline-water side of the interface, coupled with the assumption of a sloping interface, implies a vertical gradient from the transition zone into the freshwater zone. This potential for vertical movement of the interface apparently was opposed by the potential (head) on the freshwater side of the interface that kept the interface relatively stable over the range of hydrologic conditions during which the logs were run. The five flow logs for Kyle transect freshwater well KY1 all indicate upward flow that originates from the Glen Rose Limestone, the uppermost unit of the Trinity aquifer; and one log for well KY2 shows upward flow entering the borehole from the Trinity aquifer. These flow data constitute evidence of the potential for flow from the Trinity aquifer into the Edwards aquifer in the vicinity of the Kyle transect. Subsurface temperature data indicate that flow on average is more active, or vigorous, on the freshwater side of the interface than on the saline-water side. A hydraulic connection between the transition zone and the freshwater zone is indicated by similar patterns in the hydrographs of the 15 transect monitoring wells in and near the transition zone and three county index wel

Texas↗

Hydrogeologic framework of the middle San Pedro watershed, southeastern Arizona

Water managers in rural Arizona are under increasing pressure to provide sustainable supplies of water despite rapid population growth and demands for environmental protection. This report describes the results of a study of the hydrogeologic framework of the middle San Pedro watershed. The components of this report include: (1) a description of the geologic setting and depositional history of basin fill sediments that form the primary aquifer system, (2) updated bedrock altitudes underlying basin fill sediments calculated using a subsurface density model of gravity data, (3) delineation of hydrogeologic units in the basin fill using lithologic descriptions in driller's logs and models of airborne electrical resistivity data, (4) a digital three-dimensional (3D) hydrogeologic framework model (HFM) that represents spatial extents and thicknesses of the hydrogeologic units (HGUs), and (5) description of the hydrologic properties of the HGUs. The lithologic interpretations based on geophysical data and unit thickness and extent of the HGUs included in the HFM define potential configurations of hydraulic zones and parameters that can be incorporated in groundwater-flow models. The hydrogeologic framework comprises permeable and impermeable stratigraphic units: (1) bedrock, (2) sedimentary rocks predating basin-and-range deformation, (3) lower basin fill, (4) upper basin fill, and (5) stream alluvium. The bedrock unit includes Proterozoic to Cretaceous crystalline rocks, sedimentary rocks, and limestone that are relatively impermeable and poor aquifers, except for saturated portions of limestone. The pre-basin-and-range sediments underlie the lower basin fill but are relatively impermeable owing to cementation. However, they may be an important water-bearing unit where fractured. Alluvium of the lower basin fill, the main water-bearing unit, was deposited in the structural trough between the uplifted ridges of bedrock and (or) pre-basin-and-range sediments. Alluvium of the upper basin fill may be more permeable than the lower basin fill, but it is generally unsaturated in the study area. The lower basin fill stratigraphic unit was delineated into three HGUs on the basis of lithologic descriptions in driller?s logs and one-dimensional (1D) electrical models of airborne transient electromagnetic (TEM) surveys. The interbedded lower basin fill (ILBF) HGU represents an upper sequence having resistivity values between 5 and 40 ohm-m identified as interbedded sand, gravel, and clay in driller?s logs. Below this upper sequence, fine-grained lower basin fill (FLBF) HGU represents a thick silt and clay sequence having resistivity values between 5 and 20 ohm-m. Within the coarse-grained lower basin fill (CLBF) HGU, which underlies the silt and clay of the FLBF, the resistivity values on logs and 1D models increase to several hundred ohm-m and are highly variable within sand and gravel layers. These sequences match distinct resistivity and lithologic layers identified by geophysical logs in the adjacent Sierra Vista subwatershed, suggesting that these sequences are laterally continuous within both the Benson and Sierra Vista subwatersheds in the Upper San Pedro Basin. A subsurface density model based on gravity data was constructed to identify the top of bedrock and structures that may affect regional groundwater flow. The subsurface density model contains six layers having uniform density values, which are assigned on the basis of geophysical logs. The density values for the layers range between 1.65 g/cm3 for unsaturated sediments near the land surface and 2.67 g/cm3 for bedrock. Major features include three subbasins within the study area, the Huachuca City subbasin, the Tombstone subbasin, and the Benson subbasin, which have no expression in surface topography or lithology. Bedrock altitudes from the subsurface density model defined top altitudes of the bedrock HGU. The HFM includes the following HGUs in ascending stratigr

Scientific Investigations Report↗

Generalized estimates from streamflow data of annual and seasonal ground-water-recharge rates for drainage basins in New Hampshire

This report presents regression equations to estimate generalized annual and seasonal ground-water-recharge rates in drainage basins in New Hampshire. The ultimate source of water for a ground-water withdrawal is aquifer recharge from a combination of precipitation on the aquifer, ground-water flow from upland basin areas, and infiltration from streambeds to the aquifer. An assessment of ground-water availability in a basin requires that recharge rates be estimated under `normal' conditions and under assumed drought conditions. Recharge equations were developed by analyzing streamflow, basin characteristics, and precipitation at 55 unregulated continuous record stream-gaging stations in New Hampshire and in adjacent states. In the initial step, streamflow records were analyzed to estimate a series of annual and seasonal ground-water-recharge components of streamflow in each drainage basin evaluated in this study. Regression equations were then developed relating the series of annual and seasonal ground-water-recharge values to the corresponding series of annual and seasonal precipitation values as determined at the centroid of each drainage basin. This resulted in one equation for each of the 55 basins for each of the four seasonal periods and the annual period, or a total of 275 regression equations. Average annual and seasonal precipitation data for 1961-90 were then used to compute a set of normalized ground-water-recharge values that reflected the long-term average annual and seasonal variations (normalized) and mean recharge characteristics of each drainage basin. Ordinary-least-squares regression was applied in the process of selecting 10 out of 93 possible basin and climatic characteristics for further testing in the development of the equations for computing the generalized estimate of annual and seasonal ground-water recharge based on the set of normalized recharge values. Generalized-least-squares regression was used for the final parameter estimation and error evaluation. The following basin and climatic characteristics were found to be statistically significant predictors for at least one of the dependent variables: average annual, summer, and spring precipitation as determined at U.S. Geological Survey stream-gaging stations; average annual basin-centroid precipitation; average mean annual basin temperature; average minimum winter basin temperature; percent coniferous forest in a basin; percent mixed coniferous and deciduous forest in a basin; average fall basin-centroid precipitation; and average annual snowcover. These 10 basin and climatic characteristics were selected because they were statistically significant based on several statistical parameters that evaluated which combination of characteristics contributed the most to the predictive accuracy of the regression-equation models. A geographic information system is required to measure the values of the predictor variables for the equations developed in the study. The average annual normalized ground-water recharge was 21.0 in. This value was determined by generalized-least-squares (GLS) regression analysis for all of the basins used in the normalized ground-water recharge analysis for precipitation from 1961-90. The average winter (January 1-March 15) ground-water recharge was 4.3 in., average spring (March 16-May 31) ground-water recharge was 9.0 in., average summer (June 1-October 31) ground-water recharge was 4.0 in., and average fall (November 1-December 31) ground-water recharge was 3.6 in. Normalized ground-water recharge ranged annually from 12.3 to 31.8 in., for winter from 2.30 to 7.82 in., for spring from 5.16 to 13.7 in., for summer from 1.45 to 10.2 in., and for fall from 2.21 to 6.06 in.

New Hampshire↗

Ecological Requirements for Pallid Sturgeon Reproduction and Recruitment in the Lower Missouri River: A Research Synthesis 2005-08

This report provides a synthesis of results obtained between 2005 and 2008 from the Comprehensive Sturgeon Research Program, an interagency collaboration between the U.S. Geological Survey, Nebraska Game and Parks Commission, U.S. Fish and Wildlife Service, and the U.S. Army Corps of Engineers' Missouri River Recovery - Integrated Science Program. The goal of the Comprehensive Sturgeon Research Program is to improve fundamental understanding of reproductive ecology of the pallid sturgeon with the intent that improved understanding will inform river and species management decisions. Specific objectives include: *Determining movement, habitat-use, and reproductive behavior of pallid sturgeon; *Understanding reproductive physiology of pallid sturgeon and relations to environmental conditions; *Determining origin, transport, and fate of drifting pallid sturgeon larvae, and evaluating bottlenecks for recruitment of early life stages; *Quantifying availability and dynamics of aquatic habitats needed by pallid sturgeon for all life stages; and *Managing databases, integrating understanding, and publishing relevant information into the public domain. Management actions to increase reproductive success and survival of pallid sturgeon in the Lower Missouri River have been focused on flow regime, channel morphology, and propagation. Integration of 2005-08 Comprehensive Sturgeon Research Program research provides insight into linkages among flow regime, re-engineered channel morphology, and pallid sturgeon reproduction and survival. The research approach of the Comprehensive Sturgeon Research Program integrates opportunistic field studies, field-based experiments, and controlled laboratory studies. The field study plan is designed to explore the role of flow regime and associated environmental cues using two complementary approaches. An upstream-downstream approach compares sturgeon reproductive behavior between an upstream section of the Lower Missouri River with highly altered flow regime to a downstream section that maintains much of its pre-regulation flow variability. The upstream section also has the potential for an experimental approach to compare reproductive behavior in years with pulsed flow modifications ('spring rises') to years without. The reproductive cycle of the female sturgeon requires several years to progress through gonadal development, oocyte maturation, and spawning. Converging lines of evidence support the hypothesis that maturation and readiness to spawn in female sturgeon is cued many months before spawning. Information on reproductive readiness of shovelnose sturgeon indicates that sturgeon at different locations along the Lower Missouri River between St. Louis and Gavins Point Dam are all responding to the same early cue. Although not a perfect surrogate, the more abundant shovelnose sturgeon is morphologically, physiologically, and genetically similar to pallid sturgeon, and thereby provides a useful comparative model for the rarer species. Day length is the likely candidate to define a temporal spawning window. Within the spawning window, one or more additional, short-term, and specific cues may serve to signal ovulation and release of gametes. Of three potential spawning cues - water temperature, water discharge, and day of year - water temperature is the most likely proximate cue because of the fundamental physiological role temperature plays in sturgeon embryo development and survival, and the sensitivity of many fish hormones to temperature change. It also is possible that neither temperature nor discharge is cueing spawning; instead, reproductive behavior may result from the biological clock advancing an individual fish's readiness to spawn day after day through the spawning period until the right moment, independent of local environmental conditions. Separation of the individual effects of discharge events, water temperature, and other possible factors, such as proximity to male

Scientific Investigations Report↗

Water Budgets of the Walker River Basin and Walker Lake, California and Nevada

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. The only outflow from Walker Lake is evaporation from the lake surface. Between 1882 and 2008, upstream agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-feet. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes streamflow in the Walker River basin and an updated water budget of Walker Lake with emphasis on the lower Walker River basin downstream from Wabuska, Nevada. Water budgets are based on average annual flows for a 30-year period (1971-2000). Total surface-water inflow to the upper Walker River basin upstream from Wabuska was estimated to be 387,000 acre-feet per year (acre-ft/yr). About 223,000 acre-ft/yr (58 percent) is from the West Fork of the Walker River; 145,000 acre-ft/yr (37 percent) is from the East Fork of the Walker River; 17,000 acre-ft/yr (4 percent) is from the Sweetwater Range; and 2,000 acre-ft/yr (less than 1 percent) is from the Bodie Mountains, Pine Grove Hills, and western Wassuk Range. Outflow from the upper Walker River basin is 138,000 acre-ft/yr at Wabuska. About 249,000 acre-ft/yr (64 percent) of inflow is diverted for irrigation, transpired by riparian vegetation, evaporates from lakes and reservoirs, and recharges alluvial aquifers. Stream losses in Antelope, Smith, and Bridgeport Valleys are due to evaporation from reservoirs and agricultural diversions with negligible stream infiltration or riparian evapotranspiration. Diversion rates in Antelope and Smith Valleys were estimated to be 3.0 feet per year (ft/yr) in each valley. Irrigated fields receive an additional 0.8 ft of precipitation, groundwater pumpage, or both for a total applied-water rate of 3.8 ft/yr. The average corrected total evapotranspiration rate for alfalfa is 3.2 ft/yr so about 0.6 ft/yr (15 percent) flushes salts from the soil. The diversion rate in Bridgeport Valley was estimated to be 1.1 ft/yr and precipitation is 1.3 ft/yr. The total applied-water rate of 2.4 ft/yr is used to irrigate pasture grass. The total applied water rate in the East Fork of the Walker River and Mason Valley was estimated to be 4.8 ft/yr in each valley. The higher rate likely is due to appreciable infiltration, riparian evapotranspiration, or both. Assuming a diversion rate of 3.0 ft/yr, stream loss due to infiltration and riparian evapotranspiration is about 3,000 acre-ft/yr along the East Fork of the Walker River and 14,000 acre-ft/yr in Mason Valley. In the lower Walker River basin, overall and groundwater budgets were calculated for Wabuska to Schurz, Nev., and Schurz to Walker Lake. An overall water budget was calculated for the combined reaches. Imbalances in the water budgets range from 1 to 7 percent, which are insignificant statistically, so the water budgets balance. Total inflow to the Wabuska-Walker Lake reach from the river and others sources is 140,000 acre-ft/yr. Stream and subsurface discharge into the northern end of Walker Lake totals 110,000 acre-ft/yr. About 30,000 acre-ft/yr is lost on the Walker River Indian Reservation from agricultural evapotranspiration, evapotranspiration by native and invasive vegetation, domestic pumpage, and subsurface outflow from the basin through Double Spring and the Wabuska lineament. Alfalfa fields in the upper Walker River basin are lush and have an average corrected total evapotranspiration rate of 3.2 ft/yr. Alfalfa fields on the Walker River Indian Reservation are not as lush and have a total corrected evapotranspiration rate of 1.6-2.1 ft/yr, which partly could be due to alkaline soils that were submerged by Pleistocene Lake Lahontan. The total applied-water rate is 7.0 ft/yr, almost twice the

Scientific Investigations Report↗

Water pressure and ground vibrations induced by water guns near Brandon Road Lock and Dam and Lemont, Illinois

Multiple geophysical sensors were used to characterize the underwater pressure field and ground vibrations of a seismic water gun and its suitability to deter the movement of Asian carps (particularly the silver [ Hypophthalmichthys molitrix ] and bighead [ Hypophthalmichthys nobilis ] carps) while ensuring the integrity of surrounding structures. The sensors used to collect this information were blast-rated hydrophones, surface- and borehole-mounted geophones, and fixed accelerometers. Results from two separate studies are discussed in this report. The Brandon Road study took place in May 2014, in the Des Plaines River, in a concrete-walled channel downstream of the Brandon Road Lock and Dam near Joliet, Illinois. The Lemont study took place in June 2014, in a segment of the dolomite setblock-lined Chicago Sanitary and Ship Canal near Lemont, Illinois. Two criteria were evaluated to assess the potential deterrence to carp migration, and to minimize the expected effect on nearby structures from discharge of the seismic water gun. The first criterion was a 5-pound-per-square-inch (lb/in 2 ) limit for dynamic underwater pressure variations. The second criterion was a maximum velocity and acceleration disturbance of 0.75 inch per second (in/s) for sensitive machinery (such as the lock gates and pumps) and 2.0 in/s adjacent to canal walls, respectively. The criteria were based on previous studies of fish responses to dynamic pressure variations, and effects of vibrations on the structural integrity of concrete walls. The Brandon Road study evaluated the magnitude and extent of the pressure field created by two water gun configurations in the concrete-walled channel downstream of the lock where channel depths ranged from 11 to 14 feet (ft). Data from a single 80-cubic-inch (in³) water gun set at 6 ft below water surface (bws) produced a roughly cylindrical 5-lb/in 2 pressure field 20 ft in radius, oriented vertically, with the radius decreasing to less than 15 ft at the water surface. A combination of two 80-in 3 water guns set at 6 and 8 ft, respectively, produced a similarly shaped 5 lb/in 2 pressure field 30 ft in radius. Neither of the water gun configurations exceeded the given threshold of 5 lb/in 2 above the static pressure along the walls of the canal at the 700 lb/in 2 water gun input pressure. Velocity and acceleration data were collected simultaneously with the underwater pressure data to understand the response of adjacent canal walls to the water gun firings. Maximum velocity and acceleration were 0.239 in/s and 0.0188 feet per second squared (ft/s 2 ), respectively. The Lemont study replicated and expanded upon work done in 2011. The pressure field created by the water gun was evaluated in a deeper environment (about 25 ft of water depth) than that of the Brandon Road study. To replicate the 2011 study, data were collected with the same water gun placements and input pressure, but static underwater pressure monitoring was added. Two 80-in 3 water guns were suspended below a platform at depths of 4 and 14 ft bws. Pressure was lower when the gun suspended at 4 ft bws was fired as compared to firing the single gun suspended at 14 ft bws. Firing both guns simultaneously produced similar pressures to the single gun suspended at 14 ft bws. Data were collected to assess the pressure field produced by two 80-in 3 water guns separated by 80 ft and suspended at a depth of 14 ft bws. The spatial extent of the 5-lb/in 2 threshold varied substantially with gun input air pressure. Firing the water gun with an air pressure of 2,000 lb/in 2 generated a pressure field greater than the threshold at all but one location in the measured region. Additionally, the water gun with an air pressure of 1,000 lb/in 2 did not reach the threshold anywhere in the measured region. Maximum velocity and acceleration were 0.304 in/s and 0.015 ft/s 2 , respectively.

Illinois↗

General water-quality conditions, long-term trends, and network analysis at selected sites within the Ambient Water-Quality Monitoring Network in Missouri, water years 1993–2017

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, collects data pertaining to the surface-water resources of Missouri. Established in 1964, the Ambient Water-Quality Monitoring Network (AWQMN) consisted of 69 sites in 2017. Two additional sites from the National Water-Quality Program are included with the AWQMN sites for the analyses in this report. The sites are sampled typically from 2 to 12 times per year for physical properties, total suspended solids, nutrients, fecal indicator bacteria, and trace elements. The period of analysis for this study was from 1993 through 2017 and data analysis included 71 sites and 15 water-quality constituents plus discharge. Data analysis involved retrieving the data, conditioning the data for analysis, analyzing the data for trends, and analyzing the monitoring network to determine if potential data gaps or data redundancies exist in the network. Results from these analyses can be used to help manage the monitoring network into the future. Water-quality data were analyzed using several software packages to provide graphical and statistical information for interpretation of trends in the data at selected sites. Discharge data at selected sites were analyzed to determine the general trends during the analysis period and how the water-quality samples represented the range of daily mean discharges at each site. Water-quality data also were analyzed at selected sites to determine the relative sensitivity of selected sites and constituents to changes in data collection frequency. Trend analysis at selected sites using a simulated reduction in sampling frequency was completed to compare to trends obtained using monthly data to determine the potential degradation in the ability of determining trends from a reduced sampling frequency. The viability of using estimated discharge to evaluate long-term trends for sites with no continuous discharge was investigated. Data from sites were statistically compared in groups to determine the relative similarity (or difference) between sites for each water-quality constituent to identify potentially redundant sites in the monitoring network. Discharge-weighted long-term trends during 1993 through 2017 were analyzed for 15 water-quality constituents at 58 sites and results indicated there were significant single- or two-period trends in about 17 percent of the analyses. Some trends indicated improvement and some trends indicated deterioration of the general water quality at some sites in the AWQMN. No trend was indicated in about 31 percent of the analyses. The constituents pH, specific conductance, and total phosphorus showed the most frequent significant trends, and each of the 15 constituents examined had a significant trend at one or more sites. A total of 42 sites indicated at least 1 constituent with a significant single- or two-period trend, and 10 sites indicated 6 or more significant trends. Potential data gaps identified for computing discharge-weighted long-term trends in the monitoring network included the lack of collection of continuous discharge at 23 sites, insufficient sampling frequency for some constituents (dissolved chloride and total and dissolved lead and zinc) at some sites, insufficient temporal sample distribution (lack of at least one sample in each season per year) at some sites, and insufficient sampling frequency for some highly censored constituents (nutrients and total and dissolved lead and zinc) at some sites. Potential data gaps based on site spatial distribution were identified in 7 basins greater than 800 square miles. Potential site redundancies were identified in 4 basins that had an area greater than 500 square miles with a site density greater than 2 sites per 1,000 square miles. Potential site redundancies also were identified for nine site pairs by observing statistical similarities in the constituent data distributions. Sampling frequency was investigated to determine if reducing the sampling frequency of select constituents could provide a statistically similar data distribution. At 28 of 71 sites, 11 constituents had sufficient data collection frequency (approximately monthly) to allow for the creation of simulated datasets of various reduced data collection frequency. For the selected monitoring network sites analyzed, the data distribution of a simulated sampling frequency of four times per year or greater, roughly evenly distributed over the year, was not significantly different than the data distribution of the original monthly sampling frequency. Sites analyzed using varying simulated sampling frequencies tended to be more sensitive to sampling frequency changes if they were in basins classified as large or very large size and tended to be least sensitive in basins classified as small and medium size in the Ozark Plateaus Province. Simulated reduced frequency sampling analysis indicated that the constituents and measurements most sensitive to changes in sampling frequencies were water temperature, dissolved oxygen, discharge, and dissolved nitrate, and least sensitive were pH, total suspended solids, dissolved phosphorus, and total phosphorus. Discharge-weighted long-term trend analysis was repeated at 22 sites for 11 constituents using a simulated quarterly sampling frequency, and matched about 46 percent of the significant single-period trends identified using monthly data and about 65 percent of the analyses that indicated no trend using the monthly data.

Missouri↗

Water quality of the St. Clair River, Lake St. Clair, and their U.S. tributaries, 1946-2005

The St. Clair River/Lake St. Clair waterway forms an international boundary between the United States and Canada. The waters of the area are an important part of the cultural heritage of the area and serves as an important water-supply and power-generating resource; the waterway also supports an economy based largely on recreation, agriculture, and manufacturing. This report was undertaken as part of the Lake St. Clair Regional Monitoring Project for the purpose of providing a comprehensive assessment of the hydrological, chemical, and physical state of the surface water of Lake St. Clair and its tributaries. The data varied in focus and density over the period of compilation which in many cases this variation prevented the completion of statistical analyses because data did not meet minimum comparability or quality requirements for those tests. Comparison of water quality of the Belle, Black, Clinton, and Pine River Basins, as well as basins of minor rivers in the study area, showed that water quality in many of the tributaries, particularly the Clinton River and some of the minor rivers, was degraded compared to the water quality of the St. Clair River/Lake St. Clair waterway. Data analyses included comparison of nutrients, chloride, specific conductance, turbidity, biochemical oxygen demand (BOD), and pesticides among the basins and the St. Clair River. Median concentrations of total nitrate were well below the recommended USEPA total nitrogen ambient water-quality criterion of 0.54 mg/L as N for nutrient ecoregion VII for all study-area streams except the Clinton River. More than 93 percent of the phosphorus concentrations for the Belle, Black, Pine and minor river basins and 84 percent of the phosphorus concentrations for the Clinton River Basin are greater than the USEPA recommended ambient total phosphorus criterion of 0.033 mg/L for rivers and streams. Nine chloride concentrations exceeded the USEPA criterion maximum concentration (CMC) for chloride set at 860 mg/L for all study-area streams, with the six largest being in the Belle River Basin. Higher chloride concentrations were increasingly common from 2002 to 2005. The urban minor river basins had the highest median specific conductance, whereas the agricultural Pine River Basin had the lowest median specific conductance. The median values of BOD for the five basins in the study area ranged from 2.4 mg/L for the Pine River Basin to 3.2 mg/L for the Black and Clinton River Basins, whereas the median for the St. Clair River was 0.5 mg/L. In 1985, the highest concentrations of pesticides were found in samples from the mouth of the Clinton River; however, in 1996–98, the majority of high pesticide concentrations were found in samples from the Black River. Changing land-use patterns, specifically conversion of agricultural lands to urban/residential lands in the Clinton River Basin, may explain this difference. Trend analysis was done for four stream sites where adequate data were available. These analyses identified no significant water-quality changes at a stream site on the Black River, where land-use patterns have changed little in the past few decades. This stands in marked contrast to trend analysis for three stream sites in the Clinton River Basin, which has undergone significant land-use change. The changes at the Clinton River stream sites, ranging from 5 to 13 significant trends, were generally decreases in nutrients and increases in total dissolved solids (TDS) and chloride. The greater flow volume of the St. Clair River/Lake St. Clair waterway is able to assimilate incoming dissolved and suspended constituents from tributaries with little effect upon its overall water quality, although incomplete mixing may result in localized water-quality impairment downstream from tributary confluences. Mixing effects on Lake St. Clair water quality was also demonstrated in analysis of Escherichia coli ( E. coli ) data collected at paired nearshore/offshore sites, which reflected similarity in water quality among many paired sites.

Michigan↗

Trace elements and radon in groundwater across the United States, 1992-2003

Trace-element concentrations in groundwater were evaluated for samples collected between 1992 and 2003 from aquifers across the United States as part of the U.S. Geological Survey National Water-Quality Assessment Program. This study describes the first comprehensive analysis of those data by assessing occurrence (concentrations above analytical reporting levels) and by comparing concentrations to human-health benchmarks (HHBs). Data from 5,183 monitoring and drinking-water wells representing more than 40 principal and other aquifers in humid and dry regions and in various land-use settings were used in the analysis. Trace elements measured include aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn). Radon (Rn) gas also was measured and is included in the data analysis. Climate influenced the occurrence and distribution of trace elements in groundwater whereby more trace elements occurred and were found at greater concentrations in wells in drier regions of the United States than in humid regions. In particular, the concentrations of As, Ba, B, Cr, Cu, Mo, Ni, Se, Sr, U, V, and Zn were greater in the drier regions, where processes such as chemical evolution, ion complexation, evaporative concentration, and redox (oxidation-reduction) controls act to varying degrees to mobilize these elements. Al, Co, Fe, Pb, and Mn concentrations in groundwater were greater in humid regions of the United States than in dry regions, partly in response to lower groundwater pH and (or) more frequent anoxic conditions. In groundwater from humid regions, concentrations of Cu, Pb, Rn, and Zn were significantly greater in drinking-water wells than in monitoring wells. Samples from drinking-water wells in dry regions had greater concentrations of As, Ba, Pb, Li, Sr, V, and Zn, than samples from monitoring wells. In humid regions, however, concentrations of most trace elements were greater in monitoring wells than in drinking-water wells; the exceptions were Cu, Pb, Zn, and Rn. Cu, Pb, and Zn are common trace elements in pumps and pipes used in the construction of drinking-water wells, and contamination from these sources may have contributed to their concentrations. Al, Sb, Ba, B, Cr, Co, Fe, Mn, Mo, Ni, Se, Sr, and U concentrations were all greater in monitoring wells than in drinking-water wells in humid regions. Groundwater from wells in agricultural settings had greater concentrations of As, Mo, and U than groundwater from wells in urban settings, possibly owing to greater pH in the agricultural wells. Significantly greater concentrations of B, Cr, Se, Ag, Sr, and V also were found in agricultural wells in dry regions. Groundwater from dry-region urban wells had greater concentrations of Co, Fe, Pb, Li, Mn, and specific conductance than groundwater from agricultural wells. The geologic composition of aquifers and aquifer geochemistry are among the major factors affecting trace-element occurrence. Trace-element concentrations in groundwater were characterized in aquifers from eight major groups based on geologic material, including (1) unconsolidated sand and gravel; (2) glacial unconsolidated sand and gravel; (3) semiconsolidated sand; (4) sandstone; (5) sandstone and carbonate rock; (6) carbonate rock; (7) basaltic and other volcanic rock; and (8) crystalline rock. The majority of groundwater samples and the largest percentages of exceedences of HHBs were in the glacial and nonglacial unconsolidated sand and gravel aquifers; in these aquifers, As, Mn, and U are the most common trace elements exceeding HHBs. Overall, 19 percent of wells (962 of 5,097) exceeded an HHB for at least one trace element. The trace elements with HHBs included in this summary were Sb, As, Ba, Be, B, Cd, Cr,

Scientific Investigations Report↗

Abundance of host fish and frequency of glochidial parasitism in fish assessed in field and laboratory settings and frequency of juvenile mussels or glochidia recovered from hatchery-held fish, central and southeastern Texas, 2012-13

In 2012–13, the U.S. Geological Survey (USGS), in cooperation with the U.S. Fish and Wildlife Service (USFWS), completed the first phase of a two-phase study of mussel host-fish relations for five endemic mussel species in central and southeastern Texas that were State-listed as threatened on January 17, 2010: (1) Texas fatmucket ( Lampsilis bracteata ), (2) golden orb ( Quadrula aurea ), (3) smooth pimpleback ( Quadrula houstonensis ), (4) Texas pimpleback ( Quadrula petrina ), and (5) Texas fawnsfoot ( Truncilla macrodon ). On October 6, 2011, the USFWS announced the completion of a status review and determined that the five mussel species warranted listing under the Endangered Species Act; however, listing of these species at that time was precluded by higher priority listing actions, and currently (December 2014), they remained unlisted. Freshwater mussels are long-lived, sedentary organisms that spend their larval stage as obligate parasites on the gills or fins of fishes, and many of these larvae, which are referred to as “glochidia,” can survive only on a narrow range of host-fish species. Results from both study phases are likely to provide information useful for propagation of rare mussels, reintroduction of host fish, population and reproduction monitoring, habitat restoration and enhancement, and adaptive management. The abundance of host fish, frequency of parasitism in fish, and frequency of juvenile mussels or glochidia recovered from hatchery-held fish was assessed by collecting fish and mussels at 14 sites distributed among seven streams in central and southeastern Texas (juvenile mussels and glochidia were not differentiated in hatchery-held fish). All fish collected and assessed in this study were wild-caught. Qualitative surveys of the resident mussel communities were made, focusing on the five candidate species. A subsample (3 percent in 2012 and 19 percent in 2013) of the fish collected during aquatic biota surveys was submitted to the USFWS San Marcos National Fish Hatchery and Technology Center to collect juvenile mussels and glochidia recovered from the host fish, which were held for 28 days in holding tanks to allow time for most of the attached glochidia to release from the gills of the fish after transforming into juvenile mussels. All fish not sent to the hatchery were assessed for glochidia in the field or in the USGS Texas Water Science Center laboratory in Austin, Tex. Juvenile mussels and glochidia that were recovered from fish at the hatchery were submitted for use in the second phase of this study, the development of deoxyribonucleic acid (DNA) identification keys to determine mussel and host-fish relationships through DNA-based molecular identification (DNA typing of the juvenile mussels and glochidia). Reporting on the results of DNA-based molecular identification research is beyond the scope of this report. In 2012, the majority of the fish that were collected, in terms of total number and species types, belonged to the sunfish family Centrarchidae (centrarchids; 1,277 individuals and at least 10 species). Redbreast sunfish ( Lepomis auritus ) was the most common species collected in 2012 (603 individuals), but the largemouth bass ( Micropterus salmoides ) species was caught at all 10 sites. The largest number of species (19) was collected at the San Saba Menard site (San Saba River near Menard, Tex.) on May 22, 2012. In 2013, most of the fish that were collected, in terms of total number and species types, were centrarchids (763 individuals) and cyprinids (10 species), respectively. Blacktail shiner ( Cyprinella venusta ) was the most common species collected in 2013 (287 individuals), but bluegill ( Lepomis macrochirus ) was the only species that was caught at all nine sites. The largest number of individuals (382) and species (19) was collected from the Colorado Columbus site (Colorado River near Columbus, Tex.) on June 11, 2013. A minimum of two fish (any species) parasitized with glochidia was collected from each of the 10 sites sampled during 2012. The highest percentage of parasitized fish (19.1 percent) was measured at the Guadalupe Victoria site (Guadalupe River near Victoria, Tex.). The catfish family Ictaluridae (ictalurids) exhibited the highest proportion of parasitized fish (12.1 percent). Of the nine sites sampled in 2013, the Pedernales Fredericksburg site (Pedernales River near Fredericksburg, Tex.) had the highest proportion of parasitized fish at 22.7 percent. Ictalurids again exhibited the highest frequency of parasitism (26.5 percent). Of the fish that were not sent to the hatchery but assessed for glochidia in the field or in the laboratory in 2012, at least 13 species were parasitized, and longear sunfish ( Lepomis megalotis ) was the species with the highest percentage of parasitized individuals (17.3 percent). Of the fish that were not sent to the hatchery but assessed for glochidia in the field or in the laboratory in 2013, only eight species were parasitized, and flathead catfish ( Pylodictis olivaris ) was the species with the highest percentage of parasitized individuals (42.9 percent). With the exception of the San Antonio Charco site, fish were submitted to the hatchery from all sampling sites in 2013. During the first sampling period in 2013 (April 1–5), slightly more than half (16 out of 29) of the fish species (on a per site basis) that were submitted to the hatchery released juvenile mussels and glochidia. Compared to the other sampling periods in 2013, substantially fewer glochidia per fish were present on fish submitted to the hatchery during the second sampling period in 2013 (April 29–May 2). Although only two sites were sampled during the third sampling period in 2013 (June 10–11), more juvenile mussels and glochidia were recovered at the hatchery during this sampling period (107) than were recovered during the first two sampling periods in 2013 combined (102). An average of 17 juvenile mussels or glochidia was recovered per largemouth bass submitted to the hatchery from the Guadalupe Victoria site during the third sampling period. A total of 19 fish species collected at nine sites was submitted to the hatchery in 2013, and 14 of these species had juvenile mussels or glochidia that were recovered at the hatchery. The three most productive species, in terms of the average number of juvenile mussels or glochidia recovered, were longear sunfish, spotted bass, and largemouth bass, each of which averaged more than two juvenile mussels or glochidia recovered per individual.

Texas↗

Conceptual and numerical models of the glacial aquifer system north of Aberdeen, South Dakota

This U.S. Geological Survey report documents a conceptual and numerical model of the glacial aquifer system north of Aberdeen, South Dakota, that can be used to evaluate and manage the city of Aberdeen's water resources. The glacial aquifer system in the model area includes the Elm, Middle James, and Deep James aquifers, with intervening confining units composed of glacial till. The Elm aquifer ranged in thickness from less than 1 to about 95 feet (ft), with an average thickness of about 24 ft; the Middle James aquifer ranged in thickness from less than 1 to 91 ft, with an average thickness of 13 ft; and the Deep James aquifer ranged in thickness from less than 1 to 165 ft, with an average thickness of 23 ft. The confining units between the aquifers consisted of glacial till and ranged in thickness from 0 to 280 ft. The general direction of groundwater flow in the Elm aquifer in the model area was from northwest to southeast following the topography. Groundwater flow in the Middle James aquifer was to the southeast. Sparse data indicated a fairly flat potentiometric surface for the Deep James aquifer. Horizontal hydraulic conductivity for the Elm aquifer determined from aquifer tests ranged from 97 to 418 feet per day (ft/d), and a confined storage coefficient was determined to be 2.4x10 -5 . Estimates of the vertical hydraulic conductivity of the sediments separating the Elm River from the Elm aquifer, determined from the analysis of temperature gradients, ranged from 0.14 to 2.48 ft/d. Average annual precipitation in the model area was 19.6 inches per year (in/yr), and agriculture was the primary land use. Recharge to the Elm aquifer was by infiltration of precipitation through overlying outwash, lake sediments, and glacial till. The annual recharge for the model area, calculated by using a soil-water-balance method for water year (WY) 1975-2009, ranged from 0.028 inch in WY 1980 to 4.52 inches in WY 1986, with a mean of 1.56 inches. The annual potential evapotranspiration, calculated in soil-water-balance analysis, ranged from 21.8 inches in WY 1983 to 27.0 inches in WY 1985, with a mean of 24.6 inches. Water use from the glacial aquifer system primarily was from the Elm aquifer for irrigation, municipal, and suburban water supplies, and the annual rate ranged from 1.0 to 2.4 cubic feet per second (ft 3 /s). The MODFLOW-2005 numerical model represented the Elm aquifer, the Middle James aquifer, and the Deep James aquifer with model layers 1-3 respectively separated by confining layers 1-2 respectively. Groundwater flow was simulated with 75 stress periods beginning October 1, 1974, and ending September 30, 2009. Model grid spacing was 200 by 200 ft and boundaries were represented by specified-head boundaries and no-flow boundaries. The model used parameter estimation that focused on minimizing the difference between 954 observed and simulated hydraulic heads for 135 wells. Calibrated mean horizontal hydraulic conductivity values for model layers 1-3 were 94, 41, and 30 ft/d respectively. Vertical hydraulic conductivity values for confining layers 1 and 2 were 0.0002 and 0.0003 ft/d, respectively. Calibrated specific yield for model layer 1was 0.1 and specific storage ranged from 0.0003 to 0.0005 per foot. Calibrated mean recharge rates ranged from 2.5 in/yr where glacial till thickness was less than 10 ft to 0.8 in/yr where glacial till thickness was greater than 30 ft. Calibrated mean annual evapotranspiration rate was 8.8 in/yr. Simulated net streamflow gain from model layer 1 was 3.1 ft 3 /s.

South Dakota↗

Effects of Impoundments and Land-Cover Changes on Streamflows and Selected Fish Habitat in the Upper Osage River Basin, Missouri and Kansas

A study was conducted by the U.S. Geological Survey in cooperation with the Missouri Department of Conservation to estimate the effects of existing and proposed impoundments, land-cover changes, and reported water uses on streamflows in the 5,410-square mile upper Osage River Basin. The hydrologic model Hydrologic Simulation Program-FORTRAN (HSPF) was calibrated and validated to current (1995?2004 water years) regulation and water-use conditions, and scenarios were developed to evaluate differences for the same 10-years of record under pre-settlement, and proposed impoundment conditions. Analyses included quantification of changes in the magnitude, frequency, timing, and duration of streamflows under each simulation scenario. Streamflows from the simulations were used in conjunction with known streamflow-fish habitat relations to quantify effects of altered flows on fish-habitat area at selected Marais des Cygnes and Marmaton River locations. The cumulative effects of impoundments and land-cover changes were determined to substantially alter streamflows in the upper Osage River Basin model simulations spanning pre-settlement to proposed future conditions. The degree of streamflow alteration varied between major subbasins. Streamflows in the Marais des Cygnes River Basin were altered between pre-settlement and current conditions, primarily by major impoundments, with smaller changes expected with proposed regulation. Streamflows in the Little Osage River Basin were relatively unchanged between pre-settlement and current conditions with land-cover changes (primarily the conversion of native prairies to cultivated land) affecting flows more than the few current impoundments in this basin. The current peak flows in the Marmaton River Basin generally were higher than pre-settlement or proposed scenario peak flows. Of the three major subbasins, the Marmaton River Basin is likely to be the most affected by proposed impoundments. Declines in monthly minimum streamflows under a proposed impoundment scenario at the Marais des Cygnes River near the Kansas-Missouri state line, Kansas, were greatest for the lowest 10 percent of corresponding observed flows and during the driest years (2000, 2001 water years); that is, the greatest percent declines in flows under proposed conditions generally occurred during the lowest current/observed flow periods. In a small headwater basin in the Marmaton River Basin, simulated declines in minimum flows were small (generally less than 6 cubic feet per second and less than 1 cubic foot per second for 1- and 3-day scenarios), but resulted in 10 to 18 additional zero flow days for the 10-year simulation for the proposed scenarios relative to current simulated conditions. Reductions in minimum monthly flows as a result of additional impoundments generally were less than 5 cubic feet per second at the Marmaton River near Marmaton, Kansas, and resulted in 6 additional zero flow days. The greatest declines between proposed and current flows at the Marmaton River near the Kansas-Missouri state line, Missouri, generally occurred in the lower 50 percentile of the distribution of current simulated flows and during the drier simulation years (2001?2003). Proposed conditions resulted in declines in the 0-10 percentile flow values for the 1-, 3-, and 7-day durations. July, August, and October had the largest declines in proposed low flows relative to current simulated low flows for the 10-year simulation at this site. The flood frequency for the Marais des Cygnes River near the Kansas-Missouri state line was unchanged between observed and proposed conditions for the 10-year simulation, but was 450 percent greater under the pre-settlement scenarios compared to observed conditions. Flood frequency generally was greatest for the current condition scenarios in the Marmaton River Basin and least for the proposed conditions, although the effects of regulation on flood frequency decreased downstream from the Kansas-

Scientific Investigations Report↗

Selected low-flow frequency statistics for continuous-record streamgages in Georgia, 2013

This report presents the annual and monthly minimum 1- and 7-day average streamflows with the 10-year recurrence interval (1Q10 and 7Q10) for 197 continuous-record streamgages in Georgia. Streamgages used in the study included active and discontinued stations having a minimum of 10 complete climatic years of record as of September 30, 2013. The 1Q10 and 7Q10 flow statistics were computed for 85 streamgages on unregulated streams with minimal diversions upstream, 43 streamgages on regulated streams, and 69 streamgages known, or considered, to be affected by varying degrees of diversions upstream. Descriptive information for each of these streamgages, including the U.S. Geological Survey (USGS) station number, station name, latitude, longitude, county, drainage area, and period of record analyzed also is presented. Kendall’s tau nonparametric test was used to determine the statistical significance of trends in annual and monthly minimum 1-day and 7-day average flows for the 197 streamgages. Significant negative trends in the minimum annual 1-day and 7-day average streamflow were indicated for 77 of the 197 streamgages. Many of these significant negative trends are due to the period of record ending during one of the recent droughts in Georgia, particularly those streamgages with record through the 2013 water year. Long-term unregulated streamgages with 70 or more years of record indicate significant negative trends in the annual minimum 7-day average flow for central and southern Georgia. Watersheds for some of these streamgages have experienced minimal human impact, thus indicating that the significant negative trends observed in flows at the long-term streamgages may be influenced by changing climatological conditions. A Kendall-tau trend analysis of the annual air temperature and precipitation totals for Georgia indicated no significant trends. A comprehensive analysis of causes of the trends in annual and monthly minimum 1-day and 7-day average flows in central and southern Georgia is outside the scope of this study. Further study is needed to determine some of the causes, including both climatological and human impacts, of the significant negative trends in annual minimum 1-day and 7-day average flows in central and southern Georgia. To assess the changes in the annual 1Q10 and 7Q10 statistics over time for long-term continuous streamgages with significant trends in record, the annual 1Q10 and 7Q10 statistics were computed on a decadal accumulated basis for 39 streamgages having 40 or more years of record that indicated a significant trend. Records from most of the streamgages showed a decline in 7Q10 statistics for the decades of 1980–89, 1990–99, and 2000–09 because of the recent droughts in Georgia. Twenty four of the 39 streamgages had complete records from 1980 to 2010, and records from 23 of these gages exhibited a decline in the 7Q10 statistics during this period, ranging from –6.3 to –76.2 percent with a mean of –27.3 percent. No attempts were made during this study to adjust streamflow records or statistical analyses on the basis of trends. The monthly and annual 1Q10 and 7Q10 flow statistics for the entire period of record analyzed in the study are incorporated into the USGS StreamStatsDB, which is a database accessible to users through the recently released USGS StreamStats application for Georgia. StreamStats is a Web-based geographic information system that provides users with access to an assortment of analytical tools that are useful for water-resources planning and management, and for engineering design applications, such as the design of bridges. StreamStats allows users to easily obtain streamflow statistics, basin characteristics, and other information for user-selected streamgages.

Georgia↗

Per- and polyfluoroalkyl substances in groundwater from the Great Miami buried-valley aquifer, southwestern Ohio, 2019–20

Groundwater samples were collected during 2019 and 2020 from 23 wells in the Great Miami buried-valley aquifer (GM-BVA) in southwestern Ohio by the U.S. Geological Survey, in cooperation with the Miami Conservancy District, Dayton, Ohio, to determine concentrations of selected per- and polyfluoroalkyl substances (PFAS). The GM-BVA is a glacial outwash and alluvial fill aquifer that is the sole source of water supply for much of the region. Wells had total depths that ranged from 21 to 101 feet below land surface, and groundwater levels that ranged from 1.39 to 52.15 feet below land surface before sampling in 2019. Groundwater and related quality-control samples were sequentially collected from 22 of the 23 wells and analyzed for 24 different PFAS by 2 methods that used proprietary isotope-dilution based adaptations of U.S. Environmental Protection Agency (EPA) method 537.1, termed methods 1 and 2. Method 2 had smaller reporting limits (RL) for 22 of 24 PFAS analyzed and smaller detection limits (DLs) for all 24 PFAS analyzed compared with method 1, which made method 2 more sensitive to detect PFAS. Concentrations of perfluorooctanesulfonate (PFOS) in a groundwater (GW)-method 2 sample from well CL–275 of 1.9 nanograms per liter (ng/L) and perfluorooctanoate (PFOA) in a GW-method 2 sample from well BU–1106 of 2.1 ng/L were greater than their EPA interim health advisory guidances for drinking water (as of June 2022) by about 9,500 and 52,500 percent, respectively. The EPA interim health advisory guidances for PFOS (0.02 ng/L) and PFOA (0.004 ng/L) were also 65 and 215 times less, respectively, than the smallest method 2 DLs for PFOS (1.3 ng/L) and PFOA (0.86 ng/L). Other PFAS were either not detected in GM-BVA groundwater samples or were detected in concentrations less than Ohio action levels or Federal health-risk-based guidance. The most detected PFAS in groundwater was perfluorobutanesulfonate (PFBS), which had concentrations in samples from eight wells that ranged from 1.0 to 8.0 ng/L or from 0.05 to 0.4 percent of its EPA health advisory of 2,000 ng/L for drinking water. The similarity of PFBS (7.8 ng/L), perfluoropentanesulfonate (PFPeS; 8.1 ng/L), and perfluorohexanesulfonate (PFHxS; 14 ng/L) concentrations yielded from the GW-method 1 sample from well CL–275 on July 9, 2019, to those of PFBS (8.0 ng/L), PFPeS (7.8 ng/L), and PFHxS (16 ng/L) from the paired GW-method 2 sample demonstrated the capability of both methods to reproduce PFAS concentrations that were greater than their respective DLs. Non-detection of these PFAS in follow-up GW-method 1 and sequential replicate (Rep–GW-method 1) samples from CL–275 on April 21, 2020, indicated that the 2019 results represented a transient detection in groundwater. Eleven of twenty-three wells sampled in 2019 had from 1 to 4 PFAS detected in one or more groundwater samples or in a paired replicate sample: PFBS in 8 wells and 9 samples; PFHxS in 4 wells and 5 samples; and PFPeS, PFOS, perfluorobutanoate, perfluoropentanoate, PFOA, and perfluorooctanesulfonamide in 1 well and 1 sample each. More PFAS were detected in GW-method 2 samples than GW-method 1 samples because method 2 had smaller RLs and DLs. Results indicate benefits from the analysis of paired samples, sequential replicate samples, and other quality-control samples using analytical methods with sensitive RLs and DLs to verify PFAS concentrations in groundwater. Groundwater-age estimates indicate that water produced from all sampled wells had infiltrated to the water table within the 1947–present (2022) period of PFAS use or environmental presence. Eight wells with detectable PFBS in groundwater from 2019 samples also had groundwater-recharge dates that ranged from 1991 to 2016. Those ages coincided with the possible environmental presence of PFBS as a PFAS byproduct or use as an alternative to PFOS after about 2002. Two wells that had detections of PFHxS in 2019 groundwater samples also had post-2000 groundwater-recharge dates that coincided with the period of use of PFHxS as an alternative to PFOS. Six of nine wells with more than 66-percent of urban land use that was within 0.3 miles of each well, as of 2012, also had 1 to 4 PFAS detected in one of their groundwater samples. Seven of nine wells that produced groundwater in 2019 with an oxic redox category also had one or more PFAS detected in a sample.

Ohio↗

Effects of the H-3 Highway stormwater runoff on the water quality of Halawa Stream, Oahu, Hawaii, November 1998 to August 2004

Since November 1998, water-quality data have been collected from the H-3 Highway Storm Drain C, which collects runoff from a 4-mi-long viaduct, and from Halawa Stream on Oahu, Hawaii. From January 2001 to August 2004, data were collected from the storm drain and four stream sites in the Halawa Stream drainage basin as part of the State of Hawaii Department of Transportation Storm Water Monitoring Program. Data from the stormwater monitoring program have been published in annual reports. This report uses these water-quality data to explore how the highway storm-drain runoff affects Halawa Stream and the factors that might be controlling the water quality in the drainage basin. In general, concentrations of nutrients, total dissolved solids, and total suspended solids were lower in highway runoff from Storm Drain C than at stream sites upstream and downstream of Storm Drain C. The opposite trend was observed for most trace metals, which generally occurred in higher concentrations in the highway runoff from Storm Drain C than in the samples collected from Halawa Stream. The absolute contribution from Storm Drain C highway runoff, in terms of total storm loads, was much smaller than at stations upstream and downstream, whereas the constituent yields (the relative contribution per unit drainage basin area) at Storm Drain C were comparable to or higher than storm yields at stations upstream and downstream. Most constituent concentrations and loads in stormwater runoff increased in a downstream direction. The timing of the storm sampling is an important factor controlling constituent concentrations observed in stormwater runoff samples. Automated point samplers were used to collect grab samples during the period of increasing discharge of the storm throughout the stormflow peak and during the period of decreasing discharge of the storm, whereas manually collected grab samples were generally collected during the later stages near the end of the storm. Grab samples were analyzed to determine concentrations and loads at a particular point in time. Flow-weighted time composite samples from the automated point samplers were analyzed to determine mean constituent concentrations or loads during a storm. Chemical analysis of individual grab samples from the automated point sampler at Storm Drain C demonstrated the “first flush” phenomenon—higher constituent concentrations at the beginning of runoff events—for the trace metals cadmium, lead, zinc, and copper, whose concentrations were initially high during the period of increasing discharge and gradually decreased over the duration of the storm. Water-quality data from Storm Drain C and four stream sites were compared to the State of Hawaii Department of Health (HDOH) water-quality standards to determine the effects of highway storm runoff on the water quality of Halawa Stream. The geometric-mean standards and the 10- and 2-percent-of-the-time concentration standards for total nitrogen, nitrite plus nitrate, total phosphorus, total suspended solids, and turbidity were exceeded in many of the comparisons. However, these standards were not designed for stormwater sampling, in which constituent concentrations would be expected to increase for short periods of time. With the aim of enhancing the usefulness of the water-quality data, several modifications to the stormwater monitoring program are suggested. These suggestions include (1) the periodic analyzing of discrete samples from the automated point samplers over the course of a storm to get a clearer profile of the storm, from first flush to the end of the receding discharge; (2) adding an analysis of the dissolved fractions of metals to the sampling plan; (3) installation of an automatic sampler at Bridge 8 to enable sampling earlier in the storms; (4) a one-time sampling and analysis of soils upstream of Bridge 8 for base-line contaminant concentrations; (5) collection of samples from Halawa Stream during low-flow conditions to determine base-line conditions; (6) addition of the dissolved fraction of the metals chromium and nickel to the sampling plan; (7) elimination of fecal coliform and biochemical oxygen demand (BOD) analyses from the sampling plan; and (8) a study to examine the efficiency of the highway street sweeping.

Hawaii↗

Occurrence and distribution of fecal indicator bacteria, and physical and chemical indicators of water quality in streams receiving discharge from Dallas/Fort Worth International Airport and vicinity, North-Central Texas, 2008

This report, done by the U.S. Geological Survey in cooperation with Dallas/Fort Worth International (DFW) Airport in 2008, describes the occurrence and distribution of fecal indicator bacteria (fecal coliform and Escherichia [E.] coli), and the physical and chemical indicators of water quality (relative to Texas Surface Water Quality Standards), in streams receiving discharge from DFW Airport and vicinity. At sampling sites in the lower West Fork Trinity River watershed during low-flow conditions, geometric mean E. coli counts for five of the eight West Fork Trinity River watershed sampling sites exceeded the Texas Commission on Environmental Quality E. coli criterion, thus not fully supporting contact recreation. Two of the five sites with geometric means that exceeded the contact recreation criterion are airport discharge sites, which here means that the major fraction of discharge at those sites is from DFW Airport. At sampling sites in the Elm Fork Trinity River watershed during low-flow conditions, geometric mean E. coli counts exceeded the geometric mean contact recreation criterion for seven (four airport, three non-airport) of 13 sampling sites. Under low-flow conditions in the lower West Fork Trinity River watershed, E. coli counts for airport discharge sites were significantly different from (lower than) E. coli counts for non-airport sites. Under low-flow conditions in the Elm Fork Trinity River watershed, there was no significant difference between E. coli counts for airport sites and non-airport sites. During stormflow conditions, fecal indicator bacteria counts at the most downstream (integrator) sites in each watershed were considerably higher than counts at those two sites during low-flow conditions. When stormflow sample counts are included with low-flow sample counts to compute a geometric mean for each site, classification changes from fully supporting to not fully supporting contact recreation on the basis of the geometric mean contact recreation criterion. All water temperature measurements at sampling sites in the lower West Fork Trinity River watershed were less than the maximum criterion for water temperature for the lower West Fork Trinity segment. Of the measurements at sampling sites in the Elm Fork Trinity River watershed, 95 percent were less than the maximum criterion for water temperature for the Elm Fork Trinity River segment. All dissolved oxygen concentrations were greater than the minimum criterion for stream segments classified as exceptional aquatic life use. Nearly all pH measurements were within the pH criterion range for the classified segments in both watersheds, except for those at one airport site. For sampling sites in the lower West Fork Trinity River watershed, all annual average dissolved solids concentrations were less than the maximum criterion for the lower West Fork Trinity segment. For sampling sites in the Elm Fork Trinity River, nine of the 13 sites (six airport, three non-airport) had annual averages that exceeded the maximum criterion for that segment. For ammonia, 23 samples from 12 different sites had concentrations that exceeded the screening level for ammonia. Of these 12 sites, only one non-airport site had more than the required number of exceedances to indicate a screening level concern. Stormflow total suspended solids concentrations were significantly higher than low-flow concentrations at the two integrator sites. For sampling sites in the lower West Fork Trinity River watershed, all annual average chloride concentrations were less than the maximum annual average chloride concentration criterion for that segment. For the 13 sampling sites in the Elm Fork Trinity River watershed, one non-airport site had an annual average concentration that exceeded the maximum annual average chloride concentration criterion for that segment.

Scientific Investigations Report↗

Effects of Abandoned Coal-Mine Drainage on Streamflow and Water Quality in the Mahanoy Creek Basin, Schuylkill, Columbia, and Northumberland Counties, Pennsylvania, 2001

This report assesses the contaminant loading, effects to receiving streams, and possible remedial alternatives for abandoned mine drainage (AMD) within the Mahanoy Creek Basin in east-central Pennsylvania. The Mahanoy Creek Basin encompasses an area of 157 square miles (407 square kilometers) including approximately 42 square miles (109 square kilometers) underlain by the Western Middle Anthracite Field. As a result of more than 150 years of anthracite mining in the basin, ground water, surface water, and streambed sediments have been adversely affected. Leakage from streams to underground mines and elevated concentrations (above background levels) of acidity, metals, and sulfate in the AMD from flooded underground mines and (or) unreclaimed culm (waste rock) degrade the aquatic ecosystem and impair uses of the main stem of Mahanoy Creek from its headwaters to its mouth on the Susquehanna River. Various tributaries also are affected, including North Mahanoy Creek, Waste House Run, Shenandoah Creek, Zerbe Run, and two unnamed tributaries locally called Big Mine Run and Big Run. The Little Mahanoy Creek and Schwaben Creek are the only major tributaries not affected by mining. To assess the current hydrological and chemical characteristics of the AMD and its effect on receiving streams, and to identify possible remedial alternatives, the U.S. Geological Survey (USGS) began a study in 2001, in cooperation with the Pennsylvania Department of Environmental Protection and the Schuylkill Conservation District. Aquatic ecological surveys were conducted by the USGS at five stream sites during low base-flow conditions in October 2001. Twenty species of fish were identified in Schwaben Creek near Red Cross, which drains an unmined area of 22.7 square miles (58.8 square kilometers) in the lower part of the Mahanoy Creek Basin. In contrast, 14 species of fish were identified in Mahanoy Creek near its mouth at Kneass, below Schwaben Creek. The diversity and abundance of fish species in Mahanoy Creek decreased progressively upstream from 13 species at Gowen City to only 2 species each at Ashland and Girardville. White sucker (Catostomus commersoni), a pollution-tolerant species, was present at each of the surveyed reaches. The presence of fish at Girardville was unexpected because of the poor water quality and iron-encrusted streambed at this location. Generally, macroinvertebrate diversity and abundance at these sites were diminished compared to Schwaben Creek and other tributaries draining unmined basins, consistent with the observed quality of streamwater and streambed sediment. Data on the flow rate and chemistry for 35 AMD sources and 31 stream sites throughout the Mahanoy Creek Basin were collected by the USGS during high base-flow conditions in March 2001 and low base-flow conditions in August 2001. A majority of the base-flow streamwater samples met water-quality standards for pH (6.0 to 9.0); however, few samples downstream from AMD sources met criteria for acidity less than alkalinity (net alkalinity = 20 milligrams per liter as CaCO3) and concentrations of dissolved iron (0.3 milligram per liter) and total manganese (1.0 milligram per liter). Iron, aluminum, and various trace elements including cobalt, copper, lead, nickel, and zinc, were present in many streamwater samples at concentrations at which continuous exposure can not be tolerated by aquatic organisms without an unacceptable effect. Furthermore, concentrations of sulfate, iron, manganese, aluminum, and (or) beryllium in some samples exceeded drinking-water standards. Other trace elements, including antimony, arsenic, barium, cadmium, chromium, selenium, silver, and thallium, did not exceed water-quality criteria for protection of aquatic organisms or human health. Nevertheless, when considered together, concentrations of iron, manganese, arsenic, cadmium, chromium, copper, lead, nickel, and zinc in a majority of the streambed sediment samples from Mahanoy Creek and

Scientific Investigations Report↗

Development of a precipitation-runoff model to simulate unregulated streamflow in the South Fork Flathead River Basin, Montana

This report documents the development of a precipitation-runoff model for the South Fork Flathead River Basin, Mont. The Precipitation-Runoff Modeling System model, developed in cooperation with the Bureau of Reclamation, can be used to simulate daily mean unregulated streamflow upstream and downstream from Hungry Horse Reservoir for water-resources planning. Two input files are required to run the model. The time-series data file contains daily precipitation data and daily minimum and maximum air-temperature data from climate stations in and near the South Fork Flathead River Basin. The parameter file contains values of parameters that describe the basin topography, the flow network, the distribution of the precipitation and temperature data, and the hydrologic characteristics of the basin soils and vegetation. A primary-parameter file was created for simulating streamflow during the study period (water years 1967-2005). The model was calibrated for water years 1991-2005 using the primary-parameter file. This calibration was further refined using snow-covered area data for water years 2001-05. The model then was tested for water years 1967-90. Calibration targets included mean monthly and daily mean unregulated streamflow upstream from Hungry Horse Reservoir, mean monthly unregulated streamflow downstream from Hungry Horse Reservoir, basin mean monthly solar radiation and potential evapotranspiration, and daily snapshots of basin snow-covered area. Simulated streamflow generally was in better agreement with observed streamflow at the upstream gage than at the downstream gage. Upstream from the reservoir, simulated mean annual streamflow was within 0.0 percent of observed mean annual streamflow for the calibration period and was about 2 percent higher than observed mean annual streamflow for the test period. Simulated mean April-July streamflow upstream from the reservoir was about 1 percent lower than observed streamflow for the calibration period and about 4 percent higher than observed for the test period. Downstream from the reservoir, simulated mean annual streamflow was 17 percent lower than observed streamflow for the calibration period and 12 percent lower than observed streamflow for the test period. Simulated mean April-July streamflow downstream from the reservoir was 13 percent lower than observed streamflow for the calibration period and 6 percent lower than observed streamflow for the test period. Calibrating to solar radiation, potential evapotranspiration, and snow-covered area improved the model representation of evapotranspiration, snow accumulation, and snowmelt processes. Simulated basin mean monthly solar radiation values for both the calibration and test periods were within 9 percent of observed values except during the month of December (28 percent different). Simulated basin potential evapotranspiration values for both the calibration and test periods were within 10 percent of observed values except during the months of January (100 percent different) and February (13 percent different). The larger percent errors in simulated potential evaporation occurred in the winter months when observed potential evapotranspiration values were very small; in January the observed value was 0.000 inches and in February the observed value was 0.009 inches. Simulated start of melting of the snowpack occurred at about the same time as observed start of melting. The simulated snowpack accumulated to 90-100 percent snow-covered area 1 to 3 months earlier than observed snowpack. This overestimated snowpack during the winter corresponded to underestimated streamflow during the same period. In addition to the primary-parameter file, four other parameter files were created: for a "recent" period (1991-2005), a historical period (1967-90), a "wet" period (1989-97), and a "dry" period (1998-2005). For each data file of projected precipitation and air temperature, a single parameter file can be used to simulate a s

Montana;Idaho↗