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USGS1996

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1994 through March 1996

This report describes the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data presented are from January 1994 through March 1996, with a focus on data from January through March 1996 (first quarter of 1996). A complete database of ground-water withdrawals and chloride-concentration records since 1985 is maintained by the U.S. Geological Survey. Cumulative rainfall for January through March 1996 was about 30 inches, which is 9 percent less than the mean cumulative rainfall of about 33 inches for January through March. The period January through February is the end of the annual wet season, while March marks the start of the annual dry season. Ground-water withdrawal during January through March 1996 averaged 970,300 gallons per day. Withdrawal for the same 3 months in 1995 averaged 894,600 gallons per day. With- drawal patterns during the first quarter of 1996 did not change significantly since 1991, with the Cantonment and Air Operations areas supplying about 99 percent of total islandwide pumpage. At the end of March 1996, the chloride concentration of water from the elevated tanks at Cantonment and Air Operations were 47 and 80 milligrams per liter, respectively. The chloride data from all five production areas showed no significant upward or downward trends throughout the first quarter of 1996. Potable levels of chloride concentrations have been maintained by adjusting individual pumping rates, and also because of the absence of long-term droughts. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations also showed no significant trends throughout the first quarter of 1996. Chloride concentrations have been about the same since the last quarter of 1995. A fuel-pipeline leak at Air Operations in May 1991 decreased total islandwide withdrawals by 15 percent. This lost pumping capacity is being offset by increased pumpage at Cantonment. Six wells do not contribute to the water supply because they are being used to hydraulically divert fuel migration away from water-supply wells by a program of ground-water withdrawal and injection.

Open-File Report↗

USGS2020

Observed and modeled mercury and dissolved organic carbon concentrations and loads at control structure S-12D, Florida Everglades, 2013–17

Mercury (Hg) has been a contaminant of concern for several decades in South Florida, particularly in the Florida Everglades. The transport and bioavailability of Hg in aquatic systems is intimately linked to dissolved organic carbon (DOC). In aquatic systems, Hg can be converted to methylmercury (MeHg), which is the form of Hg that bioaccumulates in food webs. The bioaccumulation of MeHg poses significant health risks to wildlife and humans. Fish consumption advisories triggered by elevated Hg levels first appeared in the 1980s in South Florida. Multiple structures regulate freshwater distribution to Everglades National Park, including S-12D. This report summarizes seasonal and annual concentration and load data from late September 2013 to April 2017 for the total of (1) filter-passing total mercury (FTHg), (2) filter-passing methylmercury (FMeHg), (3) particulate total mercury (PTHg), (4) particulate methylmercury (PMeHg) and, (5) DOC discharged through control structure S-12D. The loads of Hg fractions and DOC at control structure S-12D were determined by pairing discharge data with constituent concentrations estimated by empirical models based on surrogate in situ water-quality measurements. Calculated concentrations of DOC ranged from 12.8 milligrams per liter (mg/L) to 27.9 mg/L with a mean of 18.8 mg/L during the study period. Annual loads of DOC ranged from 3,950 tons in 2015 to 10,900 tons in 2016. DOC loads increased linearly with an increase in flow, and the highest monthly DOC load of 1,630 tons was observed in February 2016. Calculated concentrations of FTHg ranged from 0.35 to 1.55 nanograms per liter (ng/L) with a mean of 0.85 ng/L during the study period. Calculated concentrations of FMeHg ranged from 0.06 ng/L to 0.24 ng/L with a mean of 0.14 ng/L during the study period. Generally, FTHg and FMeHg concentrations were lower during periods of decreased flow and higher during periods of increased flow. Calculated PTHg concentrations ranged from 0.09 ng/L to 4.19 ng/L with a mean of 0.58 ng/L during the study period. Calculated PMeHg concentrations ranged from below the limit of detection <0.01 ng/L to 0.29 ng/L with a mean of 0.03 ng/L during the study period. Loads of Hg were often zero or lowest from November to May, owing to the lack of flow or low-flow conditions. FTHg and FMeHg loads increased linearly with an increase in flow and typically were highest from June to October. During periods of increasing flow or following changes in gate operations, PTHg and PMeHg constituted a greater percentage of the total Hg load. Annual loads of total Hg (filter-passing and particulate) ranged from 254 grams in 2015 to 658 grams in 2016. FTHg was the predominant contributor to the total Hg load. Information presented herein provides the first assessment of DOC and Hg loads to Everglades National Park through control structure S-12D using continuous in situ measurements of discharge and constituent surrogates and compares the surrogate model approach to loads calculated from monthly sampling. Analysis of calculated and observed loads demonstrates the significance of flow data on calculating constituent loads.

Florida↗

USGS2018

External quality assurance project report for the National Atmospheric Deposition Program’s National Trends Network and Mercury Deposition Network, 2015–16

The U.S. Geological Survey Precipitation Chemistry Quality Assurance project operated five distinct programs to provide external quality assurance monitoring for the National Atmospheric Deposition Program’s (NADP) National Trends Network and Mercury Deposition Network during 2015–16. The National Trends Network programs include (1) a field audit program to evaluate sample contamination and stability, (2) an interlaboratory comparison program to evaluate analytical laboratory performance, and (3) a colocated sampler program to evaluate bias and variability attributed to automated precipitation samplers. The Mercury Deposition Network programs include the (4) system blank program and (5) an interlaboratory comparison program. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends for chemical constituents in wet deposition. The field audit program results indicate increased sample contamination for calcium, magnesium, and potassium relative to 2010 levels, and slight fluctuation in sodium contamination. Nitrate contamination levels dropped slightly during 2014–16, and chloride contamination leveled off between 2007 and 2016. Sulfate contamination is similar to the 2000 level. Hydrogen ion contamination has steadily decreased since 2012. Losses of ammonium and nitrate resulting from potential sample instability were negligible. The NADP Central Analytical Laboratory produced interlaboratory comparison results with low bias and variability compared to other domestic and international laboratories that support atmospheric deposition monitoring. Significant absolute bias above the magnitudes of the detection limits was observed for nitrate and sulfate concentrations, but no analyte determinations exceeded the detection limits for blanks. Colocated sampler program results from dissimilar colocated collectors indicate that the retrofit of the National Trends Network with N-CON Systems Company, Inc. precipitation collectors could cause substantial shifts in NADP annual deposition (concentration multiplied by depth) values. Median weekly relative percent differences for analyte concentrations ranged from -4 to +76 percent for cations, from 5 to 6 percent for ammonium, from +14 to +25 percent for anions, and from -21 to +8 percent for hydrogen ion contamination. By comparison, weekly absolute concentration differences for paired identical N-CON Systems Company, Inc., collectors ranged from 4–22 percent for cations; 2–9 percent for anions; 4–5 percent for ammonium; and 13–14 percent for hydrogen ion contamination. The N-CON Systems Company, Inc. collector caught more precipitation than the Aerochem Metrics Model 301 collector (ACM) at the WA99/99WA sites, but it typically caught slightly less precipitation than the ACM at ND11/11ND, sites which receive more wind and snow than WA99/99WA. Paired, identical OTT Pluvio-2 and ETI Noah IV precipitation gages were operated at the same sites. Median absolute percent differences for daily measured precipitation depths ranged from 0 to 7 percent. Annual absolute differences ranged from 0.08 percent (ETI Noah IV precipitation gages) to 11 percent (OTT Pluvio-2 precipitation gages). The Mercury Deposition Network programs include the system blank program and an interlaboratory comparison program. System blank results indicate that maximum total mercury contamination concentrations in samples were less than the third percentile of all Mercury Deposition Network sample concentrations (1.098 nanograms per liter; ng/L). The Mercury Analytical Laboratory produced chemical concentration results with low bias and variability compared with other domestic and international laboratories that support atmospheric-deposition monitoring. The laboratory’s performance results indicate a +1-ng/L shift in bias between 2015 (-0.4 ng/L) and 2016 (+0.5 ng/L).

Scientific Investigations Report↗

USGS2025

Fluvial sediment dynamics in the Shoshone River and tributaries around Willwood Dam, Park County, Wyoming

Sedimentation affects many of the aging reservoirs in the United States. Dams and water diversions from rivers have been central elements of infrastructure supporting agricultural irrigation in the arid and semiarid regions of the Western United States for more than a century. The Willwood Irrigation District diversion dam (hereafter referred to as “Willwood Dam”) in Park County, Wyoming, is approximately 12 miles northeast of Cody, Wyo.; has a structural height of 70 feet; and impounds the Shoshone River for diversion into the Willwood Canal. Willwood Dam is part of a larger irrigation scheme supported by water storage in the much larger Buffalo Bill Dam, which is approximately 20 miles upstream. In October 2016, renovation construction activities at Willwood Dam and the Willwood Canal caused an unplanned evacuation of nearly 96,000 cubic yards of fine sediment. The fine sediment release in 2016 raised concerns that ongoing sediment management at Willwood Dam could impose limits on the long-term health of the aquatic ecosystem and fish populations. The U.S. Geological Survey, in cooperation with Wyoming Department of Environmental Quality and Willwood Work Groups 2 and 3, initiated an investigation of the dynamics of sediment transport in the Shoshone River and selected tributaries between Buffalo Bill Dam and Willwood Dam. The goal of the study was to quantify sediment transport into and out of Willwood Dam on an annual, seasonal, and event basis to better understand the relative quantities of sediment coming from natural sources and human activities on the landscape. The study ran from March 2019 through October 2021 and used observations of streamflow, turbidity, and acoustic backscatter collected at streamgages upstream and downstream from Willwood Dam to quantify suspended-sediment loads into and out of the dam during irrigation and fallow seasons, precipitation-runoff events, and deliberate sediment releases. Each tributary’s relative contribution to the sediment load upstream from Willwood Dam was examined using discrete measurements of suspended-sediment concentration and bedload during irrigation and fallow seasons, precipitation events, and stable conditions. Analysis of daily precipitation and temperature data indicated that conditions in the study area during the 2019 agricultural year were wetter and colder than period of record normal, and drier and near normal temperatures for the 2020 and 2021 agricultural years. Not all sediment load records between 2019 and 2021 are complete because of rejected observations (outliers), instrument failures or fouling, and instrument removal for calibrations. Statistical modeling of suspended-sediment concentration using paired values of turbidity and acoustic backscatter produced four models that, after refinement, had coefficients of determination indicating that more than 84 percent of the variance was explained by either turbidity or acoustic backscatter. A system of rules was developed to select the model predictions based on the seasonal operations of Willwood Dam, assumptions about the grain sizes mobilized during these operations, and assumed accuracy of the models at the downstream streamgage (Shoshone River below Willwood Dam, near Ralston, Wyo. [streamgage 06284010]) under different operational conditions. The sediment budget between upstream and downstream estimates of loads was interpreted using the mean predicted values bound by their respective model prediction intervals. When mean predicted loads of one streamgage were contained in the prediction intervals of the other streamgage, and vice-versa, difference in the sediment budget were interpreted as “indeterminate.” Modeled sediment load balances demonstrated the depositional and erosional behaviors expected from the conceptual model of dam operations whereby sediment tends to accumulate during irrigation seasons when the dam is spilling over the top, and sediment tends to evacuate during the fallow seasons when it is flowing through the sluice gates at the base of the dam. The sediment load calculations using the rules-based model criteria indicated that between 14,200 and 380,000 tons of suspended sediment moved through the Shoshone River around Willwood Dam during the irrigation seasons of 2019, 2020, and 2021; 380,000 tons of suspended sediment were transported during the cool, wet year of 2019, and 14,200 tons of suspended sediment were transported in 2020, which was relatively dry. During fallow seasons 2019, 2020, and 2021, which had fewer complete records, between 1,140 and 106,000 tons of suspended sediment was estimated to have moved through the river. For all seasons except fallow season 2022, the models estimated that more sediment was released from the dam than entered the dam, but the modeled mean loads at each streamgage were nearly always within the prediction intervals of each other, making the sediment balance indeterminant. Examination of suspended-sediment loads during irrigation seasons indicated that between 65 and 85 percent of fine sediment was transported during annual high flows and storm events, with the remainder transported during steady, lower streamflows. Examination of suspended loads during fallow seasons indicated that deliberate sediment releases through Willwood Dam accounted for between 39 and 67 percent of the total sediment moved during the fallow seasons. Deliberate sediment releases from Willwood Dam had estimated net exports of between 1,360 and 22,400 tons. Between August 2017 and July 2023, suspended-sediment concentration and bedload sediment samples were collected from 9 tributaries to the Shoshone River during 137 sampling events, including stable and precipitation-runoff conditions. During irrigation season precipitation events, the mean total sediment yields ranged from 0.33 to 9.51 tons per day per square mile; during fallow season precipitation events, the mean total yields ranged from 0.04 to 0.95 ton per day per square mile. The mean total sediment yield per unit area across all samples at each tributary site ranged from 0.26 to 3.08 tons per day per square mile. Bedload was a minor fraction of the total load, constituting a mean of 4 percent across all samples; 3 and 6 percent for events and nonevents, respectively, during irrigation season; and 3 and 1 percent for events and nonevents, respectively, during the fallow season. With the exception of one tributary, Dry Creek, these mean yield values were within the range of watershed-scale background sediment yield values estimated from reservoir surveys and previous suspended-sediment studies. Imagery from irrigation seasons 2012, 2015, 2017, 2019, and 2022 was used to determine the planimetric backwater extent of the pool area in the Shoshone River behind Willwood Dam to identify any changes in sediment storage. Active river channel widths in the Shoshone River upstream from Willwood Dam were all similar between years except 2015, which was determined to be statistically different from all other years. Bathymetric data taken in the pool behind Willwood Dam during three different surveys between November 2017 and April 2022 indicated no statistically significant differences in bed elevations between the years. Results from the planimetric and bathymetric survey data provide multiple lines of evidence indicating that sediment did not accumulate behind the dam within the error of the methods used. Examination of how precipitation affects sediment transport in the Shoshone River upstream from Willwood Dam indicated that accumulated rainfall from the natural runoff events captured during the study period varied from a trace to as much as 4.26 inches, with associated predicted suspended-sediment loads varying from 112 to 232,000 tons of suspended sediment. The behavior of the sediment loads relative to accumulated precipitation did not appear to change depending on irrigation or fallow season. A model of suspended-sediment concentrations relative to the 2-day accumulated precipitation indicated that suspended-sediment concentrations in the Shoshone River upstream from Willwood Dam increased exponentially for accumulations of 0.3 inch or more; such storms accounted for 10 percent or less of precipitation events observed during the 1981 to 2018 period of record. The gaps in records, precision of the instrumentation, and large variation in grain sizes in suspended-sediment mixtures downstream from the dam made closing the sediment budgets for most seasons unattainable. The biggest recent change in sediment storage measured using the planimetric area of deposits behind Willwood Dam took place between 2015 and 2017. The main event between these two measurements was the installation of new Willwood Canal gates in October 2016, which resulted in the large unplanned sediment release. Because the sediment budgets were nearly always indeterminate and the planimetric and bathymetric data indicated little change in the bed and bank material, it is likely that the change in sediment storage behind the dam during the study period was small relative to the precision of the statistical models and other uncertainties. This body of evidence suggests that, averaged during the 3-year study period, no major changes in storage took place, and that the current operations may be keeping storage at near-equilibrium. This condition could have been initiated because the middle sluice gate has now been operational since 2014, and the sediment release in October 2016 evacuated a large amount of legacy sediment from storage. Although the uncertainties are large, sluicing events allow for controlled releases of sediment that contributed to the near equilibrium conditions observed over an annual basis during this study.

Wyoming↗

USGS1983

Reservoir-development impacts on surface-water quantity and quality in the Yampa River basin, Colorado and Wyoming

Development of coal resources and associated economy is accelerating in the Yampa River basin in northwestern Colorado and south-central Wyoming. Increased use of the water resources of the area will have a direct impact on their quantity and quality. As part of 18 surface-water projects, 35 reservoirs have been proposed with a combined total storage of 2.18 million acre-feet, 41% greater than the mean annual outflow from the basin. Three computer models were used to demonstrate methods of evaluating future impacts of reservoir development in the Yampa River basin. Four different reservoir configurations were used to simulate the effects of different degrees of proposed reservoir development. A multireservoir-flow model included both within-basin and transmountain diversions. Simulations indicated that in many cases diversion amounts would not be available for either type of diversion. A corresponding frequency analysis of reservoir storage levels indicated that most reservoirs would be operating with small percentages of total capacities and generally with less than 20% of conservation-pool volumes. Simulations using a dissolved-solids model indicated that extensive reservoir development could increase average annual concentrations at most locations. Simulations using a single-reservoir model indicated no significant occurrence of water-temperature stratification in most reservoirs due to limited reservoir storage. (USGS)

Water-Resources Investigations Report↗

USGS2008

Questa baseline and pre-mining ground-water quality investigation 22 — Groundwater budget for the Straight Creek drainage basin, Red River Valley, New Mexico, with a section on Sulphur Gulch water budget

In April 2001, the U.S. Geological Survey (USGS) and the New Mexico Environment Department (NMED) began a cooperative study to infer the pre-mining ground-water chemistry at the Molycorp molybdenum mine site in the Red River Valley. The Molycorp mine has been in operation since the 1920s. Because ground-water conditions prior to mining are not available, sites analogous to the pre-mining conditions at the mine site must be studied to infer those pre-mining conditions. The Straight Creek drainage basin (watershed) was selected as the primary analog site for this study because of its similar terrain and geology to the mine site, accessibility, potential for well construction, and minimal anthropogenic activity. The purpose of this report is to present results of a water-budget analysis of the debris-flow aquifer in the Straight Creek watershed. The water budget is based on mean annual conditions and is assumed to be steady state. For this study, the Straight Creek watershed was divided into sub-watersheds on the basis of locations of seismic lines, which were used to calculate cross-section area through the Straight Creek debris-flow deposits and underlying fractured and weathered bedrock (regolith). Water-budget components were calculated for areas upstream from and between the seismic lines. Components of the water budget were precipitation, evapotranspiration, surface-water flow, and ground-water flow under a steady-state mean annual condition. Watershed yield, defined as precipitation minus evapotranspiration, was separated into surface-water flow, ground-water flow through the debris-flow deposits and regolith, and ground-water flow through fractured bedrock. The approach to this calculation was to use Darcy's Law to calculate the flow through the cross-section area of the saturated debris-flow deposits and underlying regolith as defined by the interpreted seismic data. The amount of watershed yield unaccounted for through this section then was attributed to either surface-water flow or the component of ground-water flow through fractured bedrock. The inflow to the watershed, calculated to be 701 gallons per minute, is from precipitation. The calculated outflow from the watershed at or upstream from seismic-line 5 (the downstream-most line in Straight Creek prior to entering the Red River Valley) is 540 gallons per minute of evapotranspiration in the watershed upstream from line 5 (77.0 percent of precipitation), 5 gallons per minute of surface-water flow (0.7 percent of precipitation), 122 gallons per minute of ground-water flow through the debris-flow deposits and underlying regolith defined by the seismic data (17.4 percent of precipitation), and 34 gallons per minute of ground-water flow through fractured bedrock below the defined seismic line (4.9 percent of precipitation). The ground-water flow through the alluvium and inter-tonguing debris-flow deposits of the Red River Valley was calculated to be 5,227 gallons per minute at seismic-line 7, the first seismic line in the Red River Valley downstream from Straight Creek. The water budget indicates the amount of ground-water flow that enters the Red River alluvium from the debris-flow deposits and regolith in Straight Creek is small (about 2.3 percent; 122 gallons per minute) compared to the volume of flow that moves through the Red River alluvium. The total amount of ground-water flow from Straight Creek (156 gallons per minute; 122 gallons per minute from debris-flow deposits and regolith plus 34 gallons per minute through fractured bedrock) is about 3.0 percent of the ground-water flow calculated at line 7 for the Red River alluvium.

New Mexico↗

USGS1981

Modeled impacts of surface coal mining on dissolved solids in the Tongue River, southeastern Montana

A computer model has been developed for spatial and temporal simulation of streamflow and dissolved solids in the Tongue River from the Tongue River Dam to Miles City, Montana. User-defined plans of surface coal mining and agricultural development permit evaluation of potential changes in dissolved solids resulting from leaching of overburden material used to backfill mine pits and from withdrawal and return flow of irrigation water. Provision is made for simulation runs using increased streamflow from a proposed larger reservoir intended to replace the present Tongue River Reservoir. Simulations at mean streamflow indicated that mining 119,600 acres of federally leased coal tracts may increase by 4.8 percent the present annual dissolved-solids concentration in the Tongue River at Miles City. Simulations using the proposed Tongue River reservoir show substantial reductions in dissolved-solids concentration when paired with similar simulations using the present Tongue River Reservoir. When compared on a per-acre basis for the study area, the dewatering caused by irrigation increases dissolved-solids concentration more than the input of leachates from surface coal-mining operations. (USGS)

Montana↗

USGS1986

Beatty, Nevada: A section in U.S. Geological Survey research in radioactive waste disposal - Fiscal years 1983, 1984, and 1985 (WRI 87-4009)

A commercial low-level radioactive-waste disposal site has been operating near Beatty, Nevada, about 150 km northwest of Las Vegas, since 1962. The 32-ha site is situated in a desolate region of the Amargosa River Valley, sometimes referred to as the Amargosa Desert. Average annual precipitation is only about 114 mm. The site is underlain by 175 m of unconsolidated, generally coarse-grained, alluvial-fan and flood-plain deposits. The water table is at a depth of 90 m.

Nevada↗

USGS2010

Microclimate and limits to photosynthesis in a diverse community of hypolithic cyanobacteria in northern Australia

Hypolithic microbes, primarily cyanobacteria, inhabit the highly specialized microhabitats under translucent rocks in extreme environments. Here we report findings from hypolithic cyanobacteria found under three types of translucent rocks (quartz, prehnite, agate) in a semiarid region of tropical Australia. We investigated the photosynthetic responses of the cyanobacterial communities to light, temperature and moisture in the laboratory, and we measured the microclimatic variables of temperature and soil moisture under rocks in the field over an annual cycle. We also used molecular techniques to explore the diversity of hypolithic cyanobacteria in this community and their phylogenetic relationships within the context of hypolithic cyanobacteria from other continents. Based on the laboratory experiments, photosynthetic activity required a minimum soil moisture of 15% (by mass). Peak photosynthetic activity occurred between approximately 8°C and 42°C, though some photosynthesis occurred between −1°C and 51°C. Maximum photosynthesis rates also occurred at light levels of approximately 150–550 μmol m −2 s −1 . We used the field microclimatic data in conjunction with these measurements of photosynthetic efficiency to estimate the amount of time the hypolithic cyanobacteria could be photosynthetically active in the field. Based on these data, we estimated that conditions were appropriate for photosynthetic activity for approximately 942 h (∼75 days) during the year. The hypolithic cyanobacteria community under quartz, prehnite and agate rocks was quite diverse both within and between rock types. We identified 115 operational taxonomic units (OTUs), with each rock hosting 8–24 OTUs. A third of the cyanobacteria OTUs from northern Australia grouped with Chroococcidiopsis , a genus that has been identified from hypolithic and endolithic communities from the Gobi, Mojave, Atacama and Antarctic deserts. Several OTUs identified from northern Australia have not been reported to be associated with hypolithic communities previously.

Environmental Microbiology↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1993 through June 1995

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data presented are from January 1993 through June 1995, although the report focuses on hydrologic events from April through June 1995. Cumulative rainfall for April through June 1995 was about 14 inches which is 70 percent of the mean cumulative rainfall of about 20 inches for the same 3 months in a year. April through June is within the annual dry season. Rainfall for each month was below average from the respective mean monthly rainfall. All mean rainfall values are calculated for the fixed base period 1951-90. Ground-water withdrawal during April through June 1995 averaged 833,700 gallons per day. Withdrawal for the same 3 months in 1994 averaged 950,000 gallons per day. At the end of June 1995, the chloride concentration of the composite water supply was 57 milligrams per liter, well below the 250 milligrams per liter secondary drinking-water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply from April through June 1995 ranged between 26 and 62 milligrams per liter. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations increased since April 1995, with water from the deepest monitoring wells increasing in chloride concentra- tion by about 1000 milligrams per liter. A fuel leak at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water-supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration away from water-supply wells by recirculating about 150,000 gallons of water each day.

Open-File Report↗

USGS2020

Report of the River Master of the Delaware River for the period December 1, 2010–November 30, 2011

A Decree of the Supreme Court of the United States, entered June 7, 1954, established the position of Delaware River Master within the U.S. Geological Survey. In addition, the Decree authorizes diversion of water from the Delaware River Basin and requires compensating releases from certain reservoirs, owned by New York City, to be made under the supervision and direction of the River Master. The Decree stipulates that the River Master will furnish reports to the Court, not less frequently than annually. This report is the 58th Annual Report of the River Master of the Delaware River. It covers the 2011 River Master report year, the period from December 1, 2010, to November 30, 2011. During the report year, precipitation in the upper Delaware River Basin was 71.43 inches or 162 percent of the long-term average. On December 1, 2010, combined usable storage in the New York City reservoirs in the upper Delaware River Basin was 230.430 billion gallons or 85.1 percent of combined storage capacity. The reservoirs were at about 100 percent of usable capacity on May 31, 2011. Combined storage remained high (above 80 percent combined capacity) through November 2011. River Master operations during the year were conducted as stipulated by the Decree and the Flexible Flow Management Program. Diversions from the Delaware River Basin by New York City and New Jersey were in full compliance with the Decree. Reservoir releases were made as directed by the River Master at rates designed to meet the flow objective for the Delaware River at Montague, New Jersey, on 5 days during the report year (July 24–28, 2011). Conservation releases, designed to relieve thermal stress and protect the fishery and aquatic habitat in the tailwaters of the reservoirs, were also made during the report year. The quality of water in the Delaware Estuary between Trenton, New Jersey, and Reedy Island Jetty, Delaware, was monitored at various locations. Data on water temperature, specific conductance, dissolved oxygen, and pH were collected continuously by electronic instruments at four sites.

New York, New Jersey, Pennsylvania↗

USGS2018

Potential effects of elevated base flow and midsummer spike flow experiments on riparian vegetation along the Green River

The Upper Colorado River Endangered Fish Recovery Program has requested experimental flow releases from Flaming Gorge Dam for (1) elevated summer base flows to promote larval endangered Colorado pikeminnow, and (2) midsummer spike flows to disadvantage spawning invasive smallmouth bass. This white paper explores the effects of these proposed flow modifications on riparian vegetation and sediment deposition downstream along the Green River. Although modest in magnitude, the elevated base flows and possible associated reductions in magnitude or duration of peak flows would exacerbate a long-term trend of flow stabilization on the Green River that is already leading to proliferation of vegetation including invasive tamarisk along the channel and associated sediment deposition, channel narrowing and channel simplification. Midsummer spike flows could promote establishment of late-flowering plants like tamarisk. Because channel narrowing and simplification threaten persistence and quality of backwater and side channel features needed by endangered fish, the proposed flow modifications could lead to degradation of fish habitat. Channel narrowing and vegetation encroachment could be countered by increases in peak flows or reductions in base flows in some years and by prescription of rapid flow declines following midsummer spike flows. These strategies for reducing vegetation encroachment would need to be balanced with flow needs of other riverine resources. Use of high flows to remove unwanted vegetation is constrained by current operational guidance for Flaming Gorge Dam, which attempts to limit spills (i.e., flows greater than 8600 ft3 /s) that might contribute to cavitation and lead to dam safety concerns. Therefore, reversing vegetation encroachment is more likely to succeed if implemented while plants are still small. Annual monitoring of near-channel vegetation and topography would enable managers to prescribe a timely hydrologic response in case the proposed flow experiments lead to vegetation encroachment and habitat degradation.

Green River↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, 1991-93

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data are presented from January 1991 through December 1993. This report concentrates on data from fourth quarter 1993, and references historic data from 1991 and 1992. Total rainfall for 1993 was 95 inches which is 10 percent below the mean annual rainfall of 106 inches. In comparison, total rainfalls in 1992 and 1991 were 93 inches and 130 inches, respectively. Ground-water withdrawal has averaged 954,000 gallons per day during 1993, while with- drawals in 1992 and 1991 averaged 936,000 gallons per day and 927,000 gallons per day, respectively. In each of the five areas of ground-water produc- tion, withdrawals have remained steady since 1991. At the end of December 1993, the chloride concen- tration of the composite water supply was 36 milligrams per liter, well below the 250 milligrams per liter secondary drinking water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply during the last quarter (October through December 1993) ranged between 35 and 75 milligrams per liter. Chloride concentrations in monitoring wells at Cantonment and Air Operations decreased during the last quarter (October through December 1993) after having risen progressively during the previous quarter (July through September 1993). There has been a general trend of increasing chloride concentrations in the deeper monitoring wells since the 1992 dry season, which began in March 1992. A fuel spill at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration.

Open-File Report↗

USGS2020

Development of regional skew coefficients for selected flood durations in the Columbia River Basin, northwestern United States and British Columbia, Canada

Flood-frequency (hereinafter frequency) estimates provide information used to design, operate, and maintain hydraulic structures such as bridges and dams. Failures of these structures could cause catastrophic loss of property, life, or both. In addition to frequency estimates that use annual peak streamflow, frequency estimates of flood durations are required to safely and effectively operate the numerous dams in the Columbia River Basin of the northwestern United States, and British Columbia, Canada. Frequency studies rely on U.S. Geological Survey Guidelines for Determining Flood Flow Frequency (Bulletin 17C, published in 2018). A major consideration in estimating frequencies is the use of skew coefficients, which measure the asymmetry of flood flow distributions. Large uncertainties are associated with estimating the at-site skew coefficients directly from streamflow records, which are limited in length. Skew also is sensitive to extreme events for limited record lengths. Bulletin 17C recommends using regional skew coefficients to weight with the at-site skew estimate for more reliable frequency estimates. In this study, streamflow records from 313 unregulated U.S. Geological Survey streamgage sites and 97 regulated sites with naturalized streamflow records provided by the U.S. Army Corps of Engineers were used to develop regional skew models for the Columbia River Basin. The naturalized streamflow records were synthesized by removing regulatory components such as withdrawals and reservoir storage. Skew models were developed for 1-, 3-, 7-, 10-, 15-, 30-, and 60-day flood durations and used to estimate regional skew coefficients for the Columbia River Basin. This report used Bayesian statistical regression methods to develop and analyze regional skew models based on hydrologically important basin characteristics. After examining a suite of available basin characteristics, mean annual precipitation had the strongest correlation to skew across the flood durations. Regional skew regression models were fit using mean annual precipitation for selected subbasins in the Columbia River Basin.

Columbia River Basin↗

USGS1980

Petroleum-resource appraisal and discovery rate forecasting in partially explored regions

PART A: A model of the discovery process can be used to predict the size distribution of future petroleum discoveries in partially explored basins. The parameters of the model are estimated directly from the historical drilling record, rather than being determined by assumptions or analogies. The model is based on the concept of the area of influence of a drill hole, which states that the area of a basin exhausted by a drill hole varies with the size and shape of targets in the basin and with the density of previously drilled wells. It also uses the concept of discovery efficiency, which measures the rate of discovery within several classes of deposit size. The model was tested using 25 years of historical exploration data (1949-74) from the Denver basin. From the trend in the discovery rate (the number of discoveries per unit area exhausted), the discovery efficiencies in each class of deposit size were estimated. Using pre-1956 discovery and drilling data, the model accurately predicted the size distribution of discoveries for the 1956-74 period. PART B: A stochastic model of the discovery process has been developed to predict, using past drilling and discovery data, the distribution of future petroleum deposits in partially explored basins, and the basic mathematical properties of the model have been established. The model has two exogenous parameters, the efficiency of exploration and the effective basin size. The first parameter is the ratio of the probability that an actual exploratory well will make a discovery to the probability that a randomly sited well will make a discovery. The second parameter, the effective basin size, is the area of that part of the basin in which drillers are willing to site wells. Methods for estimating these parameters from locations of past wells and from the sizes and locations of past discoveries were derived, and the properties of estimators of the parameters were studied by simulation. PART C: This study examines the temporal properties and determinants of petroleum exploration for firms operating in the Denver basin. Expectations associated with the favorability of a specific area are modeled by using distributed lag proxy variables (of previous discoveries) and predictions from a discovery process model. In the second part of the study, a discovery process model is linked with a behavioral well-drilling model in order to predict the supply of new reserves. Results of the study indicate that the positive effects of new discoveries on drilling increase for several periods and then diminish to zero within 2? years after the deposit discovery date. Tests of alternative specifications of the argument of the distributed lag function using alternative minimum size classes of deposits produced little change in the model's explanatory power. This result suggests that, once an exploration play is underway, favorable operator expectations are sustained by the quantity of oil found per time period rather than by the discovery of specific size deposits. When predictions of the value of undiscovered deposits (generated from a discovery process model) were substituted for the expectations variable in models used to explain exploration effort, operator behavior was found to be consistent with these predictions. This result suggests that operators, on the average, were efficiently using information contained in the discovery history of the basin in carrying out their exploration plans. Comparison of the two approaches to modeling unobservable operator expectations indicates that the two models produced very similar results. The integration of the behavioral well-drilling model and discovery process model to predict the additions to reserves per unit time was successful only when the quarterly predictions were aggregated to annual values. The accuracy of the aggregated predictions was also found to be reasonably robust to errors in predictions from the behavioral well-drilling equation.

Professional Paper↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1992 through December 1994

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data presented are from January 1992 through December 1994. This report concentrates on data from October through December 1994, and references previous data from 1992 through 1994. Cumulative rainfall for October through December 1994 was 55 inches which is higher than the mean cumulative rainfall of about 31 inches for the same 3 months. Total rainfall for 1994 was 131 inches which is 24 percent higher than the mean annual rainfall of 106 inches. In com- parison, total rainfall in 1992 and 1993 were 93 inches and 95 inches, respectively. Ground-water withdrawal during October through December 1994 averaged 903,000 gallons per day, while the annual withdrawal in 1994 was 942,700 gallons per day. Annual withdrawals in 1992 and 1993 averaged 935,900 gallons per day and 953,800 gallons per day, respectively. At the end of December 1994, the chloride concentration of the composite water supply was 28 milligrams per liter, well below the 250 milligrams per liter secondary drinking-water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply from October through December 1994 ranged between 28 and 86 milligrams per liter. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations decreased in November and December, and seems to have leveled off by the end of the year. Although chloride concen- trations have decreased during the fourth quarter of 1994, there has been a general trend of increasing chloride concentrations in the deeper monitoring wells since the 1992 dry season, which began in March 1992. A fuel leak at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water-supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration by recirculating 150,000 gallons of water each day.

Open-File Report↗

USGS2015

Elk monitoring in Mount Rainier and Olympic national parks: 2008-2011 synthesis report

In 2008, the USGS collaborated with the NPS, the Muckleshoot and Puyallup Indian Tribes, and WDFW to develop a protocol tor monitor changes in abundance, population composition, and spatial distribution of elk on summer ranges in MORA and OLYM and winter ranges in OLYM. We developed double-observer sightability (DO-S) models that adjusted raw counts of elk as a function of factors influencing detection probabilities from the air, e.g. vegetation, elk group size, light, elk activity, and pilot experience. We plan to develop DO-S models for both MORA and OLYM summer ranges, but due to radiotelemetry collar failures in OLYM, we do not yet have enough data to model detection probabilities in OLYM. We analyzed results of the first 4 years of elk monitoring conducted under the new protocol from 2008-2011. Objectives of this first synthetic analysis are to: • update the DO-S model for MORA aerial survey results • examine abundance, composition, and distribution of elk trends in MORA summer ranges • establish a baseline of counts, population composition, and distribution of elk in OLYM summer ranges • examine trends in counts and distribution of elk in OLYM low-elevation winter ranges during early spring • determine environmental factors influencing abundance and composition of elk in selected MORA summer ranges and unadjusted counts of elk on selected OLYM winter ranges • review progress in developing a DO-S model for OLYM elk surveys • examine aerial survey operations and provide suggestions for future surveys. There was no trend in elk numbers in the N. Rainier TCA from 2008-2011; the trend in the S. Rainier TCA was not statistically significant but increased 3.3%/year. Maximum counts increased in the N. Rainier TCA ~6%/year. Maximum counts in the S. Rainier TCA increased at a rate of 17% annually. Due to failed radiocollars, weather, and other problems, we completed surveys in 2 of 5 OLYM summer range TCAs; no trend data are available. In OLYM winter ranges, we surveyed the Hoh TCA during early spring 2008-10 and of the S. Fork Hoh and Queets in 2008 and 2010. No surveys were done for early-spring counts in 2011 and 2012 due to high snowfall and lack of funding. Legacy early-spring surveys in OLYM since 1985 allowed us to assess trends in counts in the early-spring TCAs from 1985-2010. Counts of elk in the early-spring TCAs declined: 63% in the S. Fork Hoh, 18% in the Hoh, and 22% in the Queets Valley. We continue to develop and improve the DO-S model for application to OLYM summer surveys. In the next synthesis report, we will update findings with additional data following the 2015 field season, based on 8 years of survey results; it will be a more complete analysis of elk population trends.

Washington↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1992 through June 1994

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data are presented from January 1992 through June 1994. This report concentrates on data from 1994, and references historic data from 1992 and 1993. Total rainfall for the first half of 1994 was 51 inches which is 48 percent of the mean annual rainfall of 106 inches. In comparison, total rainfall for the first six months of 1993 and 1992 was 56 inches and 51 inches, respectively. Annual rainfall totals in 1993 and 1992 were 95 inches and 93 inches, respectively. Ground-water withdrawal has averaged 975,000 gallons per day through June 1994, while withdrawals in 1993 and 1992 averaged 954,000 gallons per day and 936,000 gallons per day, respectively. In each of the five areas of ground- water production, withdrawals have remained steady since 1991. At the end of June 1994, the chloride concentration of the composite water supply was 68 milligrams per liter, well below the 250 milligrams per liter secondary drinking water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply from January through June 1994 ranged between 37 and 90 milligrams per liter. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations have increased very slightly since March 1994 coinciding with the start of the dry season. There has been a general trend of increasing chloride concentrations in the deeper monitoring wells since the 1992 dry season, which began in March 1992. A fuel spill at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water-supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration.

Open-File Report↗