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USGS2016

Cooperative Fish and Wildlife Research Units Program—2015 Year In Review

Summary The Cooperative Fish and Wildlife Research Unit (CRU) Program had its 80th anniversary in 2015. We did not have a party, but those of us who work directly for the Unit program on a daily basis celebrate the privilege we feel in being part of one of the greatest conservation institutions in history. Our mission is our hallmark: meeting the actionable science needs of our cooperators, providing them technical guidance and assistance in interpreting and applying new advances in science, and developing the future workforce through graduate education and mentoring. Our success in accomplishing our mission is due principally to the caliber of the scientists and students they recruit, and the tremendous support from our cooperators. The National Cooperators Coalition has been active in fostering support and I am very excited about their energy. A Special Session at the 2015 North American Wildlife and Natural Resources Conference was dedicated to the Unit program, and a vision for our future was presented at this most prestigious conservation policy forum. We compiled a directory of expertise within the Unit program organized within thematic science areas as identified by our cooperators. We intend for this directory to facilitate our transboundary initiatives where two or more Units in collaboration will be the catalyst that binds agencies and organizations together on landscape scale conservation science. We are co-sponsoring a workshop at the 2016 North American conference, along with the Association of Fish and Wildlife Agencies, the American Fisheries Society, and The Wildlife Society to jump-start a dialogue on and identify issues associated with the widening gap between science and management. The CRU is viewed by our cooperators as being the standard for delivering actionable science in conservation, and the exception to the emerging trend. This is testament to the legacy of the Unit Program and the foundation it is built upon. In this Year in Review report, you will find details on staffing, vacancies, research funding, and other pertinent information. You will also see snapshots of Unit projects with information on how results have been or are being applied by cooperators. That is the essence of what we do: science that matter.

Circular↗
USGS2008

Field Methods and Quality-Assurance Plan for Quality-of-Water Activities, U.S. Geological Survey, Idaho National Laboratory, Idaho

Water-quality activities conducted by the staff of the U.S. Geological Survey (USGS) Idaho National Laboratory (INL) Project Office coincide with the USGS mission of appraising the quantity and quality of the Nation's water resources. The activities are conducted in cooperation with the U.S. Department of Energy's (DOE) Idaho Operations Office. Results of the water-quality investigations are presented in various USGS publications or in refereed scientific journals. The results of the studies are highly regarded, and they are used with confidence by researchers, regulatory and managerial agencies, and interested civic groups. In its broadest sense, quality assurance refers to doing the job right the first time. It includes the functions of planning for products, review and acceptance of the products, and an audit designed to evaluate the system that produces the products. Quality control and quality assurance differ in that quality control ensures that things are done correctly given the 'state-of-the-art' technology, and quality assurance ensures that quality control is maintained within specified limits.

Open-File Report↗
USGS2020

Evaluation of the analytical methods used to determine the elemental concentrations found in the stream geochemical dataset compiled for Alaska

A recent U.S. Geological Survey data compilation of stream-sediment geochemistry for Alaska contains decades of analyses collected under numerous Federal and State programs. The compiled data were determined by various analytical methods. Some samples were reanalyzed by a different analytical method than the original, resulting in some elements having concentrations reported by multiple analytical methods. Consideration of the analytical methods used to determine the elemental concentrations is an important step in a mineral prospectivity analysis. We used the compiled data to compare concentrations of barium (Ba), cobalt (Co), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn) determined by different analytical methods to show how simple data comparisons can identify bias and provide a general sense of the comparability of different analytical methods. The elements were selected because they have a range of geochemical properties that may affect the performance of different analytical procedures. Generally, agreement between Ba, Co, Cu, Cr, Ni, Pb, and Zn concentrations is good for most quantitative methods that use a total decomposition of the sample. However, Cr concentrations typically were lower for methods using quantitative-instrumental analysis following a multi-acid dissolution technique that included hydrofluoric acid compared to those using sinter decomposition. Additionally, low- to middle-range concentrations for Co, Cr, Cu, Ni, Pb, and Zn by instrumental neutron activation (NA) and energy-dispersive x-ray spectroscopy (EDX) analyzed by the National Uranium Resource Evaluation (NURE) program have high uncertainty. Concentrations determined by methods that use partial decomposition of the sample generally correspond well to concentrations determined by methods that use a total decomposition technique, except for Ba and Cr. For Ba and Cr, partial decomposition techniques yield lower concentrations than those determined by methods that use a total decomposition technique. Comparison of Ba, Co, Cr, Cu, Ni, Pb, and Zn concentrations determined by semiquantitative visual six-step direct-current arc emission spectrography (ES_SQ) to those determined by quantitative methods using either a total or partial decomposition technique consistently show scatter that exceeds the values expected based on the range represented by the semiquantitative concentration. The data compilation includes a best-value determination that was selected based on the analytical method from the all concentration data for that sample. Ba, Cr, Co, and Zn concentrations determined by NA usually are selected as the best-value determination. However, the NURE-NA method was designed for high throughput and the uncertainty associated with low- and mid-range concentrations is greater than that of the multi-acid method used to reanalyze many samples. Selection of the multi-acid method over the NURE-NA method for Ba, Co, and Zn could be warranted. Additionally, concentrations determined by ES_SQ usually are selected as the best-value determination over all methods that use a partial decomposition of the sample. Substitution of concentrations determined by methods that use a partial decomposition for those of ES_SQ may be warranted for Co, Cu, Ni, Pb, and Zn. Regardless of the selection of the best-value determination, the dataset remains a mixed method dataset and the uncertainty due to differences in analytical methodology must be considered when using the dataset.

Alaska↗
USGS2021

Field methods, quality-assurance, and data management plan for water-quality activities and water-level measurements, Idaho National Laboratory, Idaho

Introduction Water-quality activities and water-level measurements conducted by the U.S. Geological Survey (USGS) Idaho National Laboratory (INL) Project Office coincide with the USGS mission of appraising the quantity and quality of the Nation’s water resources. The activities are conducted in cooperation with the U.S. Department of Energy’s (DOE) Idaho Operations Office. Results of water-quality and hydraulic head investigations are presented in various USGS publications or in refereed scientific journals, and the data are stored in the National Water Information System (NWIS) database. The results of the studies are used by researchers, regulatory and managerial agencies, and civic groups. In its broadest sense, “quality assurance” refers to doing the job right the first time. It includes the functions of planning for products, review and acceptance of the products, and an audit designed to evaluate the system that produces the products. Quality control and quality assurance differ in that quality control ensures that things are done correctly given the “state-of-the-art” technology, and quality assurance ensures that quality control is maintained within specified limits.

Idaho↗
USGS2026

Field methods, quality-assurance, and data management plan for water-quality activities and water-level measurements, Idaho National Laboratory, Idaho

Introduction Water-quality activities and water-level measurements conducted by the U.S. Geological Survey (USGS) Idaho National Laboratory (INL) Project Office coincide with the USGS mission of evaluating the quantity and quality of the Nation’s water resources. The activities are conducted in cooperation with the U.S. Department of Energy’s (DOE) Idaho Operations Office. Results of water-quality and hydraulic head research efforts are presented in various USGS and scientific journal publications (refer to Fisher, 2022). These data are stored internally in the Aquarius Time Series and Aquarius Samples databases and are publicly accessible through National Water Quality Monitoring Council (2025) and U.S. Geological Survey (2025). Data collected from our studies are used by researchers, Federal and State agencies, water management and regulatory organizations, as well as the public. This quality assurance plan (QAP) describes the methods and processes for field methods, data collection, data management, data auditing, and equipment management for both the water-quality and water-level programs at the USGS INL Project Office (hereto referred to as INL Project Office). A comprehensive quality assurance (QA) plan ensures that the processes defined in this document will guide the program staff to collect and publish reliable, useful, and defensible data products for stakeholders. This QAP supersedes previous versions of this document and is intended to complement the Quality Assurance and Data Management (QADM) Plan for the Idaho Water Science Center (IDWSC; Christopher Mebane and Lauren Zinsser, written commun., 2024).

Idaho↗
USGS1994

Selected ground-water data for Yucca Mountain region, southern Nevada and eastern California, through December 1992

Tne U.S. Geological Survey. in support of the U.S. Department of Energy, Yucca Mountain Site- Characterization Project, collects, compiles, and summarizes water-resource data in the Yucca Mountain region. The data are collected to document the historical and current condition of ground-water resources, to detect and document changes in those resources through time, and to allow assessments of ground-water resources during investigations to determine the potential suitability of Yucca Mountain for storing high-level nuclear waste. Data on ground-water levels at 36 sites, ground- water discharge at 6 sites, ground-water quality at 19 sites, and ground-water withdrawals within Crater Fiat, Jackass Flats, Mercury Valley, and the Amargosa Desert are presented. Data on ground-water levels, discharges, and withdrawals collected by other agencies or as part of other programs are included to further indicate variations through time. A statistical summary of ground-water levels and median annual ground-water withdrawals in Jackass Flats is presented. The statistical summary includes the number of measurements, the maximum, minimum, and median water-level altitudes, and the average deviation of a11 water-level altitudes for selected baseline periods and for calendar year 1992. Data on ground-water quality are compared to established, proposed, or tentative primary and secondary drinking-water standards, and measures which exceeded those standards are listed for 18 sites. Detected organic compounds for which established, proposed, or tentative drinking-water standards exist also are listed.

California, Nevada↗
USGS2025

Development of regression equations to estimate flow durations, low-flow frequencies, and mean flows at ungaged stream sites in Connecticut using data through water year 2022

To aid Federal and State regulatory agencies in the effective management of water resources, the U.S. Geological Survey, in cooperation with the Connecticut Department of Energy and Environmental Protection and the Connecticut Department of Transportation, updated flow statistics for 118 streamgages and developed 47 regression equations to estimate selected flow duration, low flow, and mean flow statistics for the entire State of Connecticut, for the following: 1-, 5-, 10-, 25-, 50-, 75-, 90-, 99-percent flow durations; 7-day, 10-year low-flow frequency and 30-day, 2-year low-flow frequency; and mean flow, spring mean flow, and harmonic mean flow. In addition, regression equations were developed for monthly and seasonal flow durations, ranging from 25 to 99 percent for aquatic biological processes of salmonid spawning (November), overwinter (December–February), clupeid spawning (May), resident spawning (June), and rearing and growth (July–October) periods, and for flow durations ranging from 1 to 99 percent for the habitat forming (March–April) period. Statistics were derived from daily mean streamflow data collected from streamgages with at least 10 years of data through water year 2022 in southern New England and eastern New York. Forty streamgages in Connecticut and adjacent areas of neighboring States were used in the regression analysis. Regression methods of weighted least squares and generalized least squares were used to derive the final coefficients and measures of uncertainty for the regression equations. The equations used to estimate selected streamflow statistics were developed by relating the flow statistics to different basin characteristics (physical, land cover, and climatic) at the 40 streamgages. Nine basin characteristics served as the explanatory variables in the statewide regression equations: drainage area, percentage of area with coarse-grained stratified deposits, stream density, mean basin slope, mean basin elevation, percentage of area with hydrologic soil group A, mean monthly precipitation for November, mean seasonal precipitation in the winter (December, January, and February), and mean annual temperature. The root mean square error of the 47 equations ranged from 7.9 to 121.9 percent, with an average of 27.9 percent. The equations estimate flows most accurately near the mean (50-percent flow duration), become less accurate for low flows, and are the least accurate for extreme low flows. The root mean square error for the 50-percent flow duration is 15.1 percent, with an average of 17.6 percent across the six periods. The extreme low flow statistics of 7-day, 10-year low-flow frequency, 99-percent flow duration, and 99-percent rearing and growth period flow durations have root mean square errors of 121.9, 105.1, and 121.9 percent, respectively. The adjusted coefficient of determination of the 47 equations ranged from 73.4 to 99.5 percent, with an average of 95.1 percent.

Connecticut↗
USGS2001

Evapotranspiration from a cypress and pine forest subjected to natural fires, Volusia County, Florida, 1998-99

Daily values of evapotranspiration from a watershed in Volusia County, Florida, were estimated for a 2-year period (January 1998 through December 1999) by using an energy-budget variant of the eddy correlation method and a Priestley-Taylor model. The watershed consisted primarily of pine flatwood uplands interspersed within cypress wetlands. A drought-induced fire in spring 1998 burned about 40 percent of the watershed, most of which was subsequently logged. The model reproduced the 449 measured values of evapotranspiration reasonably well (r 2 =0.90) over a wide range of seasonal and surface-cover conditions. Annual evapotranspiration from the watershed was estimated to be 916 millimeters (36 inches) for 1998 and 1,070 millimeters (42 inches) for 1999. Evapotranspiration declined from near potential rates in the wet conditions of January 1998 to less than 50 percent of potential evapotranspiration after the fire and at the peak of the drought in June 1998. After the drought ended in early July 1998 and water levels returned to near land-surface, evapotranspiration increased sharply; however, the evapotranspiration rate was only about 60 percent of the potential rate in the burned areas, compared to about 90 percent of the potential rate in the unburned areas. This discrepancy can be explained as a result of fire damage to vegetation. Beginning in spring 1999, evapotranspiration from burned areas increased sharply relative to unburned areas, sometimes exceeding unburned evapotranspiration by almost 100 percent. Possible explanations for the dramatic increase in evapotranspiration from burned areas could include phenological changes associated with maturation or seasonality of plants that emerged after the fire or successional changes in composition of plant community within burned areas. Variations in daily evapotranspiration are primarily the result of variations in surface cover, net radiation, photosynthetically active radiation, air temperature, and water-table depth. A water budget for the watershed supports the validity of the daily measurements and estimates of evapotranspiration. A water budget constructed using independent estimates of average rates of rainfall, runoff, and deep leakage, as well as evapotranspiration, was consistent within 3.8 percent. An alternative water budget constructed using evapotrans-piration estimated by the standard eddy correlation method was consistent only within 9.1 percent. This result indicates that the standard eddy correlation method is not as accurate as the energy-budget variant.

Florida↗
USGS2014

Environmental impacts of utility-scale solar energy

Renewable energy is a promising alternative to fossil fuel-based energy, but its development can require a complex set of environmental tradeoffs. A recent increase in solar energy systems, especially large, centralized installations, underscores the urgency of understanding their environmental interactions. Synthesizing literature across numerous disciplines, we review direct and indirect environmental impacts – both beneficial and adverse – of utility-scale solar energy (USSE) development, including impacts on biodiversity, land-use and land-cover change, soils, water resources, and human health. Additionally, we review feedbacks between USSE infrastructure and land-atmosphere interactions and the potential for USSE systems to mitigate climate change. Several characteristics and development strategies of USSE systems have low environmental impacts relative to other energy systems, including other renewables. We show opportunities to increase USSE environmental co-benefits, the permitting and regulatory constraints and opportunities of USSE, and highlight future research directions to better understand the nexus between USSE and the environment. Increasing the environmental compatibility of USSE systems will maximize the efficacy of this key renewable energy source in mitigating climatic and global environmental change.

Renewable and Sustainable Energy Reviews↗
USGS2008

Geologic assessment of undiscovered gas resources of the Eastern Oregon and Washington Province

The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geology-based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States, focusing on the distribution, quantity, and availability of oil and natural gas resources. The USGS has completed an assessment of the undiscovered oil and gas potential of the Eastern Oregon and Washington Province of Oregon and Washington (USGS Province 5005). The province is a priority Energy Policy and Conservation Act (EPCA) province for the National Assessment because of its potential for oil and gas resources. The assessment of this province is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (stratigraphy, sedimentology, petrophysical properties), and hydrocarbon traps (trap formation and timing). In the Eastern Oregon and Washington Province, the USGS used this geologic framework to define one total petroleum system and two assessment units within the total petroleum system, and quantitatively estimated the undiscovered gas resources within each assessment unit.

Oregon, Washington↗
USGS1996

Geohydrology of the shallow aquifers in the Denver metropolitan area, Colorado

The Denver metropolitan area is underlain by shallow layers of water-bearing sediments (aquifers) consisting of unconsolidated gravel, sand, silt, and clay. The depth to water in these aquifers is less than 20 feet in much of the area, and the aquifers provide a ready source of water to numerous shallow, small-capacity wells. The shallow depth to water also makes the aquifers susceptible to contamination from the land surface. Water percolating downward from residential, commercial, and industrial property, spills of hazardous materials, and leaks from underground storage tanks and pipelines can cause contaminants to enter the shallow aquifers. Wet basements, unstable foundation materials, and waterlogged soils also are common in areas of very shallow ground water. Knowledge of the extent, thickness, and water-table altitude of the shallow aquifers is incomplete. This, coupled with the complexity of development in this large metropolitan area, makes effective use, management, and protection of these aquifers extremely difficult. Mapping of the geologic and hydrologic characteristics of these aquifers would provide the general public and technical users with information needed to better use, manage, and protect this water resource. A study to map the geohydrology of shallow aquifers in the Denver metropolitan area was begun in 1994. The work was undertaken by the U.S. Geological Survey in cooperation with the U.S. Army-Rocky Mountain Arsenal, U.S. Department of Energy-Rocky Flats Field Office, Colorado Department of Public Health and Environment, Colorado Department of Natural Resources-State Engineers Office, Denver Water Department, Littleton-Englewood Wastewater Treatment Plant, East Cherry Creek Valley Water and Sanitation District, Metro Wastewater Reclamation District, Willows Water District, and the cities of Aurora, Lakewood, and Thornton. This report presents the results of a systematic mapping of the extent, thickness, and water-table altitude of the shallow aquifers in a 700-square-mile part of the greater Denver metropolitan area (fig. 1). The five sheets in this report (figs. 2-7) show (1) the thickness and extent of the unconsolidated sediments that overlie bedrock formations in the area, (2) the altitude and configuration of the buried bedrock surface, (3) the altitude of the water table and direction of ground-water movement, (4) the saturated thickness of the shallow aquifers, and (5) the depth to the water table in the shallow aquifers. The maps primarily are intended to indicate the general trends in altitude and thickness of the aquifers and are not intended to define conditions at specific sites.

Hydrologic Atlas↗
USGS1981

Activities in Idaho; status of projects, fiscal year 1981

Twenty-three projects were conducted by the Water Resources Division of the U.S. Geological Survey in Idaho during fiscal year 1981. These projects were made in cooperation with 6 State and local and 11 Federal agencies. State and local cooperative funding amounted to $720,670; Federal funding amounted to $2,437,628. Eighty-three persons were employed--40 full time and 43 other than full time. In addition, the Water Resources Division maintains a project office at the Idaho National Engineering Laboratory. Work there is done in cooperation with the U.S. Department of Energy, the sole funding source. Projects other than continuing programs for collection of hydrologic data included flood-characteristics and flood-mapping studies, geothermal-resource investigations, ground-water quality assessments, basin- and region-wide water-resource investigations, river quality-of-water monitoring studies, volcanic-ash related studies, and ground-water-trends and stream-gaging program evaluations.

Idaho↗
USGS2022

Dynamic estimates of geologic CO2 storage resources in the Illinois Basin constrained by reinjectivity of brine extracted for pressure management

Geologic carbon storage (GCS) is likely to be an important part of global efforts to decarbonize the energy industry. Widespread deployment of GCS relies on strategies to maximize CO 2 injection rates while minimizing reservoir pressurization that could induce seismicity and/or fluid leakage into groundwater resources. Brine extraction from CO 2 storage formations with subsurface reinjection elsewhere could mitigate pressure buildup associated with GCS. Therefore, evaluation of CO 2 storage resources should consider the injectivity of produced brine in geologic layers above or below the CO 2 storage formation. For this study, a methodology was developed to estimate brine injectivity from formation depth and thickness using flow modeling and optimization techniques. The methodology was demonstrated in the Illinois Basin, where GCS in the Mt. Simon Sandstone is ongoing. Based on pressure constraints and considering only regions of the shallower units where salinity and sealing conditions were met, maximum brine injection rates were estimated within the Mt. Simon and three overlying hydrostratigraphic layers. Results indicate that a large area exists where CO 2 injectivity could be optimized by brine extraction and reinjection.

Illinois, Indiana↗
USGS2013

Actual evapotranspiration (water use) assessment of the Colorado River Basin at the Landsat resolution using the operational simplified surface energy balance model

Accurately estimating consumptive water use in the Colorado River Basin (CRB) is important for assessing and managing limited water resources in the basin. Increasing water demand from various sectors may threaten long-term sustainability of the water supply in the arid southwestern United States. We have developed a first-ever basin-wide actual evapotranspiration (ET a ) map of the CRB at the Landsat scale for water use assessment at the field level. We used the operational Simplified Surface Energy Balance (SSEBop) model for estimating ET a using 328 cloud-free Landsat images acquired during 2010. Our results show that cropland had the highest ET a among all land cover classes except for water. Validation using eddy covariance measured ET a showed that the SSEBop model nicely captured the variability in annual ET a with an overall R 2 of 0.78 and a mean bias error of about 10%. Comparison with water balance-based ETa showed good agreement (R 2 = 0.85) at the sub-basin level. Though there was good correlation (R 2 = 0.79) between Moderate Resolution Imaging Spectroradiometer (MODIS)-based ETa (1 km spatial resolution) and Landsat-based ET a (30 m spatial resolution), the spatial distribution of MODIS-based ET a was not suitable for water use assessment at the field level. In contrast, Landsat-based ET a has good potential to be used at the field level for water management. With further validation using multiple years and sites, our methodology can be applied for regular production of ET a maps of larger areas such as the conterminous United States.

Arizona, California, Colorado, Nevada, New Mexico,↗
USGS2009

Dietary segregation of pelagic and littoral fish assemblages in a highly modified tidal freshwater estuary

Estuarine food webs are highly variable and complex, making identification of their trophic pathways difficult. Energy for the food web of the San Francisco Estuary is thought to be based largely on in situ phytoplankton production, but little attention has been paid to littoral habitats, where other energy sources may be important. We analyzed the stomach contents of over 960 juvenile fishes and the stable carbon and nitrogen isotope ratios of these fishes and their potential food resources in pelagic and littoral habitats from the tidal freshwater area of the estuary. The mixing model IsoSource was used to examine energy sources important to consumers. Our results show evidence of two predominant food web pathways. Pelagic fishes and some littoral fishes showed strong dependence on a zooplankton–phytoplankton trophic pathway. However, the majority of fishes in littoral habitats had diets and carbon isotope ratios consistent with energy arising from submerged aquatic vegetation and epiphytic macroalgae. IsoSource revealed that the overall majority of nutrition of littoral fishes originated from consumption of grazer amphipods. Examining both stable isotopes and stomach contents allowed us to identify a food web with contributions to resident fishes that had been previously underestimated in the estuary. This study provides insight to how estuarine food webs have changed over the last few decades and highlights why the functions of habitats must be understood for effective restoration planning.

Marine and Coastal Fisheries: Dynamics, Management↗
USGS2023

Understanding fatality patterns and sex ratios of Brazilian free-tailed bats (Tadarida brasiliensis) at wind energy facilities in western California and Texas

Background Operation of wind turbines has resulted in collision fatalities for several bat species, and one proven method to reduce these fatalities is to limit wind turbine blade rotation ( i.e ., curtail turbines) when fatalities are expected to be highest. Implementation of curtailment can potentially be optimized by targeting times when females are most at risk, as the proportion of females limits the growth and stability of many bat populations. The Brazilian free-tailed bat ( Tadarida brasiliensis ) is the most common bat fatality at wind energy facilities in California and Texas, and yet there are few available data on the sex ratios of the carcasses that are found. Understanding the sex ratios of fatalities in California and Texas could aid in planning population conservation strategies such as informed curtailment. Methods We used PCR to determine the sex of bat carcasses collected from wind energy facilities during post-construction monitoring (PCM) studies in California and Texas. In California, we received samples from two locations within the Altamont Pass Wind Resource Area in Alameda County: Golden Hills (GH) ( n = 212) and Golden Hills North (GHN) ( n = 312). In Texas, we received samples from three wind energy facilities: Los Mirasoles (LM) (Hidalgo County and Starr County) ( n = 252), Los Vientos (LV) (Starr County) ( n = 568), and Wind Farm A (WFA) (San Patricio County and Bee County) ( n = 393). Results In California, the sex ratios of fatalities did not differ from 50:50, and the sex ratio remained stable over the survey years, but the seasonal timing of peak fatalities was inconsistent. In 2017 and 2018, fatalities peaked between September and October, whereas in 2019 and 2020 fatalities peaked between May and June. In Texas, sex ratios of fatalities varied between locations, with Los Vientos being female-skewed and Wind Farm A being male-skewed. The sex ratio of fatalities was also inconsistent over time. Lastly, for each location in Texas with multiple years studied, we observed a decrease in the proportion of female fatalities over time. Discussion We observed unexpected variation in the seasonal timing of peak fatalities in California and differences in the sex ratio of fatalities across time and facility location in Texas. In Texas, proximity to different roost types (bridge or cave) likely influenced the sex ratio of fatalities at wind energy facilities. Due to the inconsistencies in the timing of peak female fatalities, we were unable to determine an optimum curtailment period; however, there may be location-specific trends that warrant future investigation. More research should be done over the entirety of the bat active season to better understand these trends in Texas. In addition, standardization of PCM studies could assist future research efforts, enhance current monitoring efforts, and facilitate research on post-construction monitoring studies.

California, Texas↗
USGS2025

Estimating agricultural irrigation water consumption for the High Plains aquifer region with integrated energy- and water-balance evapotranspiration modeling approaches

Estimation of irrigation water use provides essential information for the management and conservation of agricultural water resources. Conventionally, water use data are created based on reports and surveys from water users, whereas manual records may not be complete due to lacking flow meters, measurement gaps, inconsistent methods across regions, and time- and cost-consuming data processing. Alternatively, spatially explicit estimation of irrigation water use can be conducted efficiently using remote sensing evapotranspiration (ET) modeling approaches. In this study, we created a gridded blue water evapotranspiration (BWET) dataset to estimate historical irrigation water consumption (1986 – 2020) in the croplands across the United States High Plains aquifer region. The BWET data were generated by integrating an energy-balance ET model [Operational Simplified Surface Energy Balance model (SSEBop)] and a water-balance ET model [Vegetation ET model (VegET)]. BWET in croplands indicates crop consumptive use of irrigation water extracted from surface water and groundwater resources. The BWET estimates were compared with reported irrigation water use data for all counties within the aquifer region. The results revealed high agreement between growing season (May – September) BWET and annual water withdrawal at county level. Specifically, correlation coefficients of volumetric BWET and water withdrawal were 0.90 and 0.96, respectively, for the entire aquifer region and western Kansas. The timeseries of BWET and water withdrawal showed similar temporal trends and high covariations. The BWET estimates were systematically lower than the water withdrawal measurements, which was primarily attributed to blue water losses in the irrigation system. The irrigation efficiency, calculated as the ratio of BWET to water withdrawal depth, was 0.57 and 0.74 for the entire aquifer region and western Kansas, respectively. This study demonstrates the capability of using satellite-based ET models (e.g., SSEBop and VegET) to efficiently estimate crop water consumption and evaluate irrigation efficiency at landscape, county, and regional scales.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS2021

Plasma metabolite indices are robust to extrinsic variation and useful indicators of foraging habitat quality in Lesser Scaup

Energy acquisition and storage are important for survival and fecundity of birds during resource-limited periods such as spring migration. Plasma-lipid metabolites (i.e. triglyceride [TRIG], β-hydroxybutyrate [BOHB]) have been used to index changes in lipid stores and, thus, have utility for assessing foraging habitat quality during migration. However, such an index may be affected by energetic maintenance costs, diet, and other factors, and further validation under experimental conditions is needed to understand potential sources of variation and verify existing indices. We evaluated a plasma-lipid metabolite index using 30 female and 28 male wild Lesser Scaup ( Aythya affinis ; hereafter scaup) held in short-term captivity (~24 hr) during spring migration. Similar to previous observational studies, BOHB was negatively associated and TRIG was positively associated with mass change ( R 2 = 0.68). BOHB estimates were nearly identical to those published on free-living scaup, but TRIG estimates differed from free-living scaup and varied by sex, with females having a greater rate of predicted mass change than captive and free-living males. Our results suggest TRIG may be a better measure of energy income than deposition because lipid deposition likely varies with energetic maintenance costs, stress, and underlying physiological processes while TRIG relates primarily to energy income. In contrast, BOHB was a reliable predictor of negative mass change across sexes. The sex-based differences in apparent lipid deposition rates warrant further research before a generalizable model is advisable for comparing mass change predictions across studies. However, if predictions are standardized, this technique is generally robust to variations in energy income vs. lipid deposition across sexes. Accordingly, our evaluation provides verification for the utility of plasma-lipid metabolites as an indicator of foraging habitat quality during migration.

Illinois↗