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USGS2003

Topography and Sedimentation Characteristics of the Squaw Creek National Wildlife Refuge, Holt County, Missouri, 1937-2002

The Squaw Creek National Wildlife Refuge (hereafter referred to as the Refuge), located on the Missouri River floodplain in northwest Missouri, was established in 1935 to provide habitat for migratory birds and wildlife. Results of 1937 and 1964 topographic surveys indicate that sedimenta-tion, primarily from Squaw Creek and Davis Creek inflows, had substantially reduced Refuge pool volumes and depths. A study was undertaken by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to quantify and spatially analyze historic rates of sedimentation in the Refuge and determine the surface elevations, depths, and pool capacities for selected managed pools from a 2002 survey.The 1937 to 1964 mean total sediment depo-sition, in the area corresponding to the 2002 sur-veyed pool area (about 4,900 acres), was 1.26 ft (feet), or 0.047 ft/yr (foot per year). Mean annual rates of deposition, by pool, from 1937 to 1964 varied from 0.016 to 0.083 ft/yr. From 1964 to 2002, the mean total sediment deposition in the 2002 surveyed pools was 0.753 ft, or 0.020 ft/yr. Therefore, the mean rate of sediment-depth accu-mulation from 1964 to 2002 was about 42 percent of the mean 1937 to 1964 rate, or a 58 percent reduction. Mean annual rates of deposition by pool from 1964 to 2002 varied from 0.010 to 0.049 ft/yr. Despite a substantial reduction in the average sediment accumulation rate for the Refuge, 5 of the 15 separate pools for which annual rates were calculated for both periods showed a small increase in the deposition rates of up to 0.008 ft/yr. Sediment deposits have resulted in a sub-stantial cumulative loss of volume in the Refuge pools since 1937. The 1937 to 2002 total sediment volume deposited in the 2002 surveyed pool area was about 9,900 acre-ft (acre-feet), or 152 acre-ft/yr (acre-feet per year). The volume of sediment deposited from 1937 to 1964 for these pools was about 6,200 acre-ft, or 230 acre-ft/yr. The volume deposited from 1964 to 2002 was about 3,700 acre-ft, or 97.3 acre-ft/yr.Bulk density values were determined from sediment cores collected from 22 sites in the Ref-uge and the bulk densities, along with sediment volumes, allowed for the calculation of sediment mass contributions to the Refuge. From 1937 to 2002, about 10,300,000 tons of sediment were deposited in the 2002 surveyed area, or 32.4 tons/acre/yr (tons per acre per year). The total computed mass of sediment deposited between 1937 and 1964 was about 6,510,000 tons, or an average of 49.1 tons/acre/yr. The total mass depos-ited from 1964 to 2002 in surveyed pools was about 3,830,000 tons, or an average of 20.5 tons/acre/yr. As with sediment thickness compari-sons, the rate of sediment mass deposition between 1964 to 2002 was about 42 percent of that from 1937 to 1964, or a 58 percent reduction.The greatest amounts of sediment deposition in the Refuge for 1937 to 2002 have been near the Squaw Creek and Davis Creek inflow spillway locations. Sediment depths in some areas near former inflow locations have exceeded 8 ft. Relo-cation of an inflow spillway effectively reduced additional sediment deposition at the original loca-tion, and caused increased sedimentation at the new inflow location. This is most clearly depicted in a pool located in the north section of the Refuge that directly received Squaw Creek inflows from 1937 to 1964 and had a mean deposition rate of 0.081 ft/yr reduced to 0.012 ft/yr, from 1964 to 2002, after inflows were redirected and erosion-management plans were implemented in the con-tributing basins.

Water-Resources Investigations Report↗

USGS1990

Procedures and rationale for marking sea otters captured and treated during the T/V Exxon Valdez oil spill

Four methods were used for marking sea otters ( Enhydra lutris ) captured and treated during the response to the T/V Exxon Valdez oil spill. Colored and numbered flipper tags were placed on each sea otter that was brought to the otter treatment centers. These tags allowed individual recognition and permitted the tracking of individuals through the treatment and holding processes. Recovery of tagged carcasses may provide a crude measure of the fates of rehabilitated otters. Seven sea otters were instrumented with radio transmitters attached to flipper tags as part of a pilot release program. The results of that study were inconclusive. Forty-five sea otters were implanted with radio transmitters as part of a study to assess the fate of rehabilitated sea otters. Specific objectives of the study include estimating survived rates and monitoring the reproductive success of the sample of rehabilitated sea otters and comparing the results with similar variables in a control population. Transponder chips were injected in the perianal region of all but seven of the instrumented sea otters, and all were tagged with red flipper tags. The advantages and disadvantages of each type of tag are discussed.

Alaska↗

USGS2018

Promoting synergy in the innovative use of environmental data—Workshop summary

From December 2 to 4, 2015, NatureServe and the U.S. Geological Survey organized and hosted a biodiversity and ecological informatics workshop at the U.S. Department of the Interior in Washington, D.C. The workshop objective was to identify user-driven future directions and areas of collaboration in advanced applications of environmental data applied to forecasting and decision making for the sustainability of biodiversity and ecosystem services. Substantial effort to recruit attendees from diverse Federal, State, and private sector organizations successfully attracted participants from 20 Federal agencies and 48 different institutions in the academic, nonprofit, State government, and commercial sectors; the total number of attendees ranged from 100 to 144 during the 3-day workshop. The first one-half of the workshop was divided into 7 plenary sessions and 3 sets of lightning talk sessions organized by sector, providing 48 oral and visual plenary presentations that shared diverse perspectives on biodiversity and ecological informatics, including original biospatial analyses from 6 graduate student map contest winners. The second one-half of the workshop focused on 10 breakout sessions with participant-driven themes from the environmental data sphere and concluded with an address by the Director of the U.S. Fish and Wildlife Service. The workshop was structured to encourage interactivity. About 80–90 percent of attendees provided direct feedback using clicker devices for specific questions related to biodiversity and ecological data uses and needs, and 10 breakout session leaders shared the highlights of their group discussions during the final workshop plenary sessions. Participants were encouraged to use the Twitter hashtag #ShareUrData. Over lunch on day 2 there were 20 simultaneous presentations of tools and apps during a special “Tools Café” session. The 10 participant-defined breakout session topics are listed below: Ecosystem services and ecological indicators Inventory and monitoring Biogeographic map of the Nation Pollinators Invasive species Remote sensing Drivers of agricultural change Citizen science Climate Hydrology and watersheds Numerous common themes that emerged from the workshop include the following: The vital importance of completing foundational environmental datasets that are nationally consistent and are essential to multiple sectors, such as the Soil Survey Geographic database high-resolution soils data, a minimum 5-meter resolution digital elevation model, national hydrographic data, high-resolution land cover data, time series high-resolution spatial climate data from historical to future time steps, and a national wetland inventory. Improved, nationally consistent environmental datasets (integrated with targeted observations) will dramatically advance forecasting capacity and support early warning systems (that is, drought, forest disease); however, multiagency coordination should focus on decision support tools that convey appropriate actions and responses to adapt to, and mitigate, potential negative consequences. Digitizing and providing access to the vast stores of underused historical data that can be leveraged for this purpose is of national importance. Modern computational techniques and the ever-increasing flow of environmental data from ground and remote observations can support improved understanding of environmental change. Success of understanding patterns of change for decision making requires establishing baselines from which change can be measured. The value of digitized historical data is greater than ever before. There is a need to recognize the multifaceted potential of citizen science to engage the public in resource stewardship, to create the next generation of science, technology, engineering, math, and environmental leaders, and to have sufficient field personnel to monitor environmental trends, including early detection of alien invasive species, phenological shifts, shifting distribution and abundance of indicator species, and species inventories. The Federal government has an essential role in creating the infrastructure to dramatically improve mobilization of citizen science (and other) data by fostering the following: creation of data standards, creation of nationally consistent framework datasets, vertical integration of observation data, visualization and dissemination of aggregated datasets, and calculation and communication of derived trends. Current and near future trends in the availability of remotely sensed data (rapid expansion of satellite fleets and drones) is revolutionizing access to near-real-time ecological data. Targeted integration with ground-based observations and instrumentation has an extremely valuable role in validating remotely sensed data, filling data gaps, improving data quality, and fully realizing the potential of the near-real-time monitoring of environmental indicator trends. Integrated management of environmental data at the landscape scale is required even as specific actions on the ground are largely local in nature. The workshop highlighted numerous success stories; however, almost every breakout group pointed out the still-too-fragmented nature of the current data landscape. Management and delivery of the necessary data, tools, and analyses to sustain our Nation’s environmental capital must be a collaborative effort between Federal, State, and local governments, academia, nonprofits, and the commercial sector, even though the responsibilities of each sector are different.

Open-File Report↗

USGS2004

Migration stopover ecology of western avian populations: A southwestern migration workshop

The importance of migration stopover sites in ensuring that migratory birds successfully accomplish their journeys between breeding and non-breeding ranges has come to the forefront of avian research. Migratory birds that breed in western United States (US) and Canada and overwinter primarily in western Mexico migrate across the arid region of northern Mexico and southwestern US. Many of these migrants use lowland riparian stopover habitats, which comprise less than 0.1% of the western U.S. landscape. These habitats represent a significant conservation priority. Recognizing the importance of migration stopover habitats in the arid southwest, the U.S. Fish and Wildlife Service (USFWS) Region 6 partnered with the U.S. Geological Survey (USGS) to support a project---“Migration stopover ecology of western avian populations: patterns of geographic and habitat distribution.” A primary objective of the project was to convene a workshop for avian researchers, conservation professionals, and land managers involved in stopover needs of migratory birds that breed in western North America. The workshop included presentations on our current state of knowledge regarding passerine migration in western North America, techniques and technologies potentially useful in researching migration, and efforts that agencies and other partners are conducting within the realm of migration. Workshop presentations provided a backdrop for subsequent discussions, the goals of which were to identify research needs and initiate a coordinated approach to research of western migration stopover ecology. Workshop presentations spanned a wide range of concerns and interests. Highlights included indications that mid- and high-elevation riparian and montane shrubland habitats may be as crucial to western migrants in fall migration as lowland riparian habitats are in spring migration. Comparisons of eastern versus western migration systems elucidated large differences in stopover habitats used and the intensity with which certain types are used, underscoring the potential need to develop separate management approaches for eastern and western stopover sites. Presentations on techniques and technology for migration research revealed that rate of lipid deposition can serve as an indicator of habitat quality; that genetics and stable isotope analyses of feathers can be valuable tools to elucidate linkages between breeding and wintering areas; that radar imagery can be used to track large-scale movement patterns and habitat use; and that there are analytical options for combining multiple sources of information. Other presentations focused on partnership perspectives (USFWS and Sonoran Joint Venture), the genesis of a western migration monitoring network, premises of Coordinated Bird Monitoring, and how collaborative efforts could benefit migration research (e.g., combined bird and bat migration studies; linking avian researchers with fluvial geomorphologists; linking research throughout western North America; linking surveys and banding). Priority research needs and questions identified during the open discussions fell into three main categories: (1) habitat/landscape/climate relationships, (2) en route bird distribution patterns, and (3) general migration ecology. Tasks within these categories included: define the relative importance of various habitat types to migrants in spring and fall, determine what distinguishes high- from poor-quality stopover habitat; determine geographic patterns of loss in stopover habitats; model landscape attributes associated with species richness and abundance; identify effects of climate change and current climate anomalies on plant phonologies, associated insect flushes, and timing of migration; and determine effects of hydrologic changes on riparian vegetation, food availability, and stopover habitat quality. Workshop participants discussed a coordinated approach for addressing immediate research needs regarding migration patterns and crucial stopover sites and types. They envisioned a three-tiered, coordinated approach: (1) long-term research to address effects of climate change and other large-scale patterns, (2) intensive, short-term survey and monitoring efforts using a stratified random design within habitats of interest to elucidate regional patterns of distribution and habitat use, and (3) research conducted at existing survey and banding sites to address more in-depth questions (e.g., rates of lipid deposition, microhabitat use, isotope analyses). There was considerable interest in developing common research proposals to blend the broad expertise represented at this workshop. A second meeting is recommended to build on the momentum of these discussions, to facilitate collaborations, and further the goals of integrated approaches to broadscale research on migration stopover ecology.

Open-File Report↗

USGS2020

Population and habitat analyses for greater sage-grouse (Centrocercus urophasianus) in the bi-state distinct population segment—2018 update

Executive Summary The Bi-State Distinct Population Segment (Bi-State DPS) of greater sage-grouse ( Centrocercus urophasianus , hereinafter “sage-grouse”) represents a genetically distinct and geographically isolated population that straddles the border between Nevada and California. The primary threat to these sage-grouse populations is the expansion of single-leaf pinyon ( Pinus monophylla ) and Utah juniper ( Juniperus osteosperma ) into sagebrush ecosystems, which fragments and reduces population connectivity and survival. Other important threats include low water availability during brood-rearing, particularly during drought, and increased predation by common ravens ( Corvus corax ), a generalist predator often associated with anthropogenic resource subsidies. Although the Bi-State DPS occurs at high elevations relative to sage-grouse range-wide, changes in historical wildfire cycles and the conversion of native shrubs to invasive annual grasslands still threaten these populations. The Bi-State DPS has undergone multiple federal status assessments and associated litigation. For example, in October of 2013, the Bi-State DPS was proposed for listing as threatened under the Endangered Species Act of 1973 by the U.S. Fish and Wildlife Service (USFWS), then withdrawn in April 2015. The withdrawal decision was challenged, and in May 2018, a Federal district court ordered the withdrawal decision to be vacated, and USFWS was required to re-open the October 2013 listing evaluation. In response, the U.S. Geological Survey (USGS), with State and Federal collaborators, embarked on a multipronged analysis to provide current and best available science regarding population status of sage-grouse within the Bi-State DPS. Using data from a long-term monitoring program, we carried out four analytical study objectives, and here, we provide preliminary results of these analyses. First, we used integrated population modeling (IPM) to predict annual population abundance and annual finite rate of population change for the Bi-State DPS, as a whole, and for each subpopulation between 1995 and 2018. Because sage-grouse exhibit population cycles (periodic increases and decreases in abundance across approximately 6- to 10-year wavelengths), we estimated trends across three nested temporal scales that represent one (11 years), two (18 years), and three (24 years) complete population cycles. These estimates of relatively long-term averaged population change account for temporal (that is, interannual) variation. Our model predicted population abundance for the Bi-State DPS during 2018 at 3,305 individuals (2,247–4,683), with the majority occupying Bodie Hills and Long Valley. The model also predicted cyclic dynamics in abundance through time with evidence of 24-year population growth and slight trends of decline over the past 18 years. Specifically, across the Bi-State DPS as a whole, we estimated annual average at 0.99, 0.99, and 1.02 over the one, two, and three population cycles, which equated to a 10.5 percent, 16.6 percent decrease, and 60.0 percent increase in abundance over the 11-, 18-, and 24-year cycles. Estimated abundance in 2018 had not reached numbers lower than those predicted during 1995. However, we found spatial variation in population trends across the three cycles. Bodie Hills subpopulation comprised the greatest (1,521) and exhibited average annual greater than 1.0 across all periods resulting in average annual increases of 7 percent. This relatively large subpopulation has grown 5 times larger than what was predicted in 1995 while experiencing cyclical dynamics within that period. Conversely, other smaller subpopulations within the Bi-State DPS exhibited average annual equal to or less than 1.0 resulting in estimated 10-year risks of extirpation ranging from 2.0 to 76.1 percent. In general, evidence of decline among smaller subpopulations was greatest for the most recent period (2008–18) compared to a period that encompassed three full population cycles (24-year). This difference coincides with an intense period of drought that began in 2012. For comparative purposes as part of this first objective, we conducted a similar analysis for populations of sage-grouse within Nevada and California but outside the Bi-State DPS. We developed a region-wide and distance-weighted IPM using lek count from Nevada Department of Wildlife (NDOW) and California Department of Fish and Wildlife (CDFW) databases and with telemetry data collected by USGS across 12 sage-grouse subpopulations. Our models predicted similar patterns in population cycling outside the Bi-State DPS but with much stronger evidence of long-term declines across 24 years. Specifically, median averaged across each year of the 11-, 18-, and 24-year periods resulted in average annual values of 0.94, 0.97, and 0.99, respectively. These values equate to 41.0 percent, 38.5 percent, and 21.3 percent declines over the corresponding periods. Second, we used lek count data in a state-space modeling framework to compare trends in population abundance across different spatial scales (that is, leks versus Bi-State DPS). This hierarchical framework allowed us to disentangle declines associated with climate conditions as opposed to other local level factors that might signal the need for management intervention. Specifically, we identified 7 leks that were both declining and recently decoupled from larger spatial scale trends, typically governed by climatic conditions (referred to as soft or hard signals). The goal of this analysis was to provide an early warning system that might have implications for conservation actions at local scales. Third, we developed phenological (spring, summer–fall, and winter) and reproductive life stage (nesting, early brood-rearing, and late-brood rearing) based resource selection functions using various environmental covariates. We report rankings of variable importance for each season and life stage, developed maps of habitat selection indices (HSI), binned categories representing low, moderate, and high classes of quality (where any category greater than or equal to low indicated selected habitat) for each phenological season and life stage, and produced composite maps by selected phenological and reproductive stage to estimate annual habitat. Fourth, we used for each lek within the Bi-State DPS to carry out a spatial analysis that quantified substantial changes in the distribution of occupied habitat across long- (24-year) and short- (11-year) term periods. Owing to differences among available datasets, the long-term analysis primarily reflected spatial shifts among subpopulations comprising the majority of the Bi-State DPS (that is, Bodie Hills and Long Valley) while the short-term analysis also quantified changes among subpopulations along the periphery. Over long and short-term periods, the overall distribution of occupied habitat (as measured by 99 percent utilization distributions intersecting any quantified habitat) was reduced by 20,573 ha and 55,492 ha, respectively. Occupied core areas (as measured by 50 percent utilization distributions intersecting any quantified habitat) over long-term periods were solely located in Bodie Hills and Long Valley. Although nearly all subpopulations experienced contractions in occupied overall and core distribution, Bodie Hills experienced spatial expansion that occurred with concomitant spatial contraction at Long Valley over both periods. Subpopulations at the northern (Pine Nuts), central (Sagehen) and southern (White-Mountains) extents of the Bi-State DPS also experienced spatial contraction over the short-term period. These findings, coupled with those of population trends, indicate long-term patterns in redistribution of sage-grouse from Long Valley and peripheral subpopulations to Bodie Hills. That is, sage-grouse subpopulations at the periphery are declining while the largest population at the core is increasing, which could have meaningful impacts on overall metapopulation persistence. We provide evidence for loss of occupied habitat (reduced distribution) given local extirpation of subpopulations. Fifth, we calculated percentages of selected phenological, life stage, and annual habitat that each subpopulation contributed to the Bi-State DPS. We then intersected these maps with a composite estimate of occupied habitat from the fourth objective and calculated percentages of selected habitat likely occupied by sage-grouse that each subpopulation contributed to the Bi-State DPS. These values provide evidence for loss of occupied habitat and subsequent reductions in spatial distribution given reductions in abundance and, in some cases, extirpation of leks within subpopulations. Lastly, we carried out an initial in-depth analysis of selection for irrigated pastures and wet meadows during the brood-rearing stage for the Long Valley subpopulation. We chose this subpopulation because it represents a population core, representing 26.5 percent of total sage-grouse within the Bi-State DPS, and has exhibited long-term declines in abundance and distribution. This subpopulation is highly sensitive to precipitation and other factors that influence water availability. Models predicted higher use of the interior portions of irrigated pastures and wet meadows during late brood-rearing period, which represented a potentially risky use of habitat that was exacerbated during periods of low moisture (for example, drought, reduced water delivery, or both). Sage-grouse typically used edges of riparian areas and pastures, largely because the interior of these mesic areas consisted of considerably less overhead concealment cover (for example, shrubs) that likely resulted in a higher risk of mortality. We found that a lack of water delivery to pastures in the form of overwinter precipitation or diversion ditches increased the movements of sage-grouse to the interior of pastures. Although further investigation of water delivery impacts on chick survival are warrented, our initial findings regarding resource selection may explain recent declines in population growth at Long Valley.

California, Nevada↗

USGS2009

Assessment of Local Recharge Area Characteristics of Four Caves in Northern Arkansas and Northeastern Oklahoma, 2004-07

A study was conducted from 2004 to 2007 by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service to assess the characteristics of the local recharge areas of four caves in northern Arkansas and northeastern Oklahoma that provide habitat for a number of unique organisms. Characterization of the local recharge areas are important because the caves occur in a predominately karst system and because land use proximal to the caves, including areas suspected to lie within the local recharge areas, may include activities with potentially deleterious effects to cave water quality. An integrated approach was used to determine the hydrogeologic characteristics and the extent of the local recharge areas of Civil War Cave, January-Stansbury Cave, Nesbitt Spring Cave, and Wasson's Mud Cave. This approach incorporated methods of hydrology, structural geology, geomorphology, and geochemistry. Continuous water-level and water-temperature data were collected at each cave for various periods to determine recharge characteristics. Field investigations were conducted to determine surficial controls affecting the groundwater flow and connections of the groundwater system to land-surface processes in each study area. Qualitative groundwater tracing also was conducted at each cave to help define the local recharge areas. These independent methods of investigation provided multiple lines of evidence for effectively describing the behavior of these complex hydrologic systems. Civil War Cave is located near the city of Bentonville in Benton County, Arkansas, and provides habitat for the Ozark cavefish. Civil War Cave is developed entirely within the epikarst of the upper Boone Formation, and recharge to Civil War Cave occurs from the Boone Formation (Springfield Plateau aquifer). The daily mean discharge for the period of study was 0.59 cubic feet per second and ranged from 0.19 to 2.8 cubic feet per second. The mean water temperature for Civil War Cave was 14.0 degrees Celsius. The calculated recharge area for Civil War Cave ranged from 0.13 to 2.5 square miles using the water-balance equation to 3.80 square miles using a normalized base-flow method. Tracer tests indicated a portion of the water within Civil War Cave was from across a major topographic divide located to the southwest. January-Stansbury Cave is located in Delaware County in northeastern Oklahoma, and provides habitat for the Oklahoma cave crayfish and the Ozark cavefish. January-Stansbury Cave is developed in the St. Joe Limestone member of the Boone Formation. The daily mean discharge for the period of study was 1.0 cubic foot per second and ranged from 0.35 to 8.7 cubic feet per second. The mean water temperature for January-Stansbury Cave was 14.3 degrees. The calculated recharge area for January-Stansbury Cave using the water-balance equation ranged from approximately 0.04 to 0.83 square miles. Tracer tests generally showed water discharging from January-Stansbury Cave during high flow originates from within the topographic drainage area and from an area outside the topographic drainage area to the southwest. Nesbitt Spring Cave is located near the city of Mountain View in north-central Arkansas and provides habitat for the Hell Creek cave crayfish. Nesbitt Spring Cave is developed in the Plattin Limestone (Ozark aquifer) and is recharged through the Boone Formation (Springfield Plateau aquifer). The mean daily discharge for the period of study was 4.5 cubic feet per second and ranged from 0.39 to 70.7 cubic feet per second. The mean water temperature for Nesbitt Spring Cave was 14.2 degrees Celsius. The calculated recharge area for Nesbitt Spring Cave using the water-balance equation ranged from 0.49 square mile to 4.0 square miles. Tracer tests generally showed a portion of water discharging from Nesbitt Spring during high flow originates from outside the topographic drainage area. Wasson's Mud Cave is located near the city of Springtown

Scientific Investigations Report↗

USGS2025

Insights and strategic opportunities from the USGS 2024 Per- and Polyfluoroalkyl Substances (PFAS) Interagency Workshop

Introduction In 2021, the U.S. Geological Survey (USGS) published Circular 1490 titled, “Integrated Science for the Study of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in the Environment: A Strategic Science Vision for the U.S. Geological Survey” (Tokranov and others, 2021). Circular 1490 was created to be a resource for USGS scientists prioritizing and planning research related to per- and polyfluoroalkyl substances (PFAS) and to be a guide for developing partnerships with other scientists, State and Federal agencies, and stakeholders engaged in PFAS research and management and mitigation of the environmental and human-health effects of PFAS. This USGS PFAS Strategic Science Vision document was intended to be the foundation for a “living strategic vision,” periodically providing updates on the state of USGS PFAS research, emerging PFAS data gaps and needs, and progress on interagency and stakeholder PFAS partnerships and priorities. To meet this objective, the USGS planned to host an Interagency and Stakeholder PFAS Workshop every 2–3 years. During September 10–12, 2024, the USGS hosted the first Interagency and Stakeholder PFAS Workshop in Reston, Virginia. The Workshop brought together experts from other Federal agencies (U.S. Environmental Protection Agency, National Institute of Environmental Health Sciences, Food and Drug Administration, Department of Defense [Air Force, Army]), State agencies (Washington Fish and Wildlife, Virginia Department of Transportation), and academia (Harvard University, University of Maryland) to address key challenges relating to the measurement and modeling of PFAS and the implications for environmental health. Participants engaged in in-depth discussions centered around six pivotal topics related to PFAS: (1) sampling protocols, methods and interpretation; (2) environmental sources, source apportionment, and occurrence; (3) environmental fate and transport; (4) human and wildlife exposure routes and risk; (5) bioconcentration, bioaccumulation, and biomagnification; and (6) ecotoxicology and effects. Each topic had three breakout sessions. A recurrent theme of workshop discussions was how data on a nationwide scale for PFAS occurrence in various environmental matrices, including air, water, food crops, biota, soil, and streambed sediment could help to advance scientific understanding. Participants noted significant geospatial data gaps, particularly in the midwestern and southern United States and the Pacific Northwest. PFAS data collection tends to be more robust along the eastern seaboard and in California. Participants stressed how enhancing the integration of large and small datasets across various agencies could help to support national scale understanding of PFAS. To address these gaps, attendees suggested leveraging datasets from Federal entities like the USGS and the U.S. Department of Defense, State agencies, and municipal utility services to develop predictive contaminant detection and transport models. Improved coordination between water quality programs and USGS research could help to facilitate access to valuable data, leading to comprehensive databases that inform PFAS point (wastewater treatment plants and landfills) and nonpoint (runoff from land, atmospheric deposition, food packaging) sources, environmental transport mechanisms, environmental detection and concentrations, potential exposure routes, and health effects on different biota, including humans. A specific request was made to develop a map demarking the depth of modern (1953 or later) groundwater, which is susceptible to surface-derived anthropogenic (that is, human-made) contamination, based on tritium-age dating. Emphasis was placed on incorporation of hydrology, groundwater flow paths, groundwater–surface water interactions, and landscape factors in predictive statistical models as a step to improve contaminant source identification and tracking. Molecular fingerprinting approaches garnered attention as techniques to link specific PFAS mixtures detected in a sample to environmental sources and levels in biota (Dávila-Santiago and others, 2022). Integrating data from abiotic (that is, water, soil, and air) and biotic (that is, living organisms) systems identified as a research opportunity. For example, understanding the composition of soils and sediments, which include a mixture of mineral, plant, and animal components, could advance understanding of exposure pathways. The discussions highlighted opportunities to explore and understand the potential redistribution and biotic exposures of PFAS from biosolid and wastewater treatment plant effluent land application practices, in addition to atmospheric releases and discharges from landfill and wastewater treatment plants. Participants identified research gaps surrounding how these sources may contribute to contamination and may affect surrounding ecosystems, including a better definition of anthropogenic background concentrations. Moving forward, the collection of co-occurrence data was noted as a means to improve understanding of complex mixtures and to leverage companion modeling efforts focused on areas with high and low contamination levels to identify areas of concern and unaffected resources. Participants emphasized how centralized USGS databases and the establishment of sample-metadata archives can help to ensure that samples are preserved and accessible for future research. In conclusion, the workshop participants identified opportunities to bridge data gaps and improve measurement techniques, modeling frameworks, databases, and communication, to enhance the understanding of PFAS and their effects on environmental and human health. Upon completion of the workshop, participants indicated an interest in developing strategic data collection, modeling, and analytical approaches to address these challenges.

Open-File Report↗

USGS1976

Recycling ground water in Waushara County, Wisconsin : resource management for cold-water fish hatcheries

Recycling water within the local ground-water system can increase the quantity of water available for use, control or avoid environmental pollution, and control temperature of the water supply. Pumped ground water supplied a fish-rearing facility for 15 months, and the waste water recharged the local ground-water system through an infiltration pond. Eighty-three percent of the recharged water returned to the well (recycled). Make-up water from the ground-water system provided the remaining 17 percent. Pumping 300 gallons per minute (20 litres per second), combined with recycling, resulted in water-level declines equivalent to a pumping rate of approximately 50 gallons per minute (3 litres per second). Using this effective pumping rate in the Theis nonequilibrium equation resulted in predicted drawdowns within 0.5 foot (0.2 metres) of those observed throughout the 15-month period. The concentration of nitrate in the water supply increased only slightly during the 15 months of recycling. Nitrate levels in a closed recycling system (100 percent recycling efficiency) would have reached 9 milligrams per litre, but observed levels did not exceed 4 milligrams per litre, and at the end of the recycling period they were lower than the initial levels. Mass-balance equations relate observed nitrate levels to the loading imposed on the system, the pumping rate, the volume of ground water affected by recycling, and the recycling efficiency. The equations predict nitrate concentrations (or other ions not attenuated by movement through the unsaturated part of the aquifer) within 1 milligram per litre of observed concentrations except during periods when nutrients are used in plant growth. The method does not account for nutrients utilized by aquatic vegetation in the infiltration pond, so that observed levels would usually be even lower than predicted. The predicted response of the local groundwater system to a nutrient loading equivalent to that generated by a hatchery producing approximately 100,000 pounds (50,000 kilograms) of trout and salmon per year indicates that maximum nitrate levels would remain significantly below the limit established by the State of Wisconsin (and the U.S. Public Health Service, 1962) for drinking water. The water-supply temperature can be maintained within the optimum range for trout and salmon rearing (10.0° to 15.5°C or 50° to 60°F) during recycling. Continuous recycling during the study period resulted in watersupply temperatures ranging between 7.0° and 14.0°C (45° and 57°F). Longterm continuous recycling would result in water-supply temperatures ranging between 7.0° and 14.5°C (45° and 58°F). Selective recycling (recycling water for only 8 months of the year) would provide water-supply temperatures ranging from 9.5° to 15.5°C (49° to 60°F). A permanent recharge pond with supplementary ponds would fulfill the needs of a hatchery development at the Greenwood Wildlife Refuge site, Waushara County, Wisconsin, and insure protection of the ground-water system. Eighty percent or more of the water pumped could be recycled by recharging waste water near the supply well. Selective recycling (recharging water to the ground-water system outside the zone of recycling during approximately 4 months of each year) could maintain optimum water-supply temperatures, reduce water-level declines by 50 percent (compared to no recycling), maintain nitrate levels in the water supply below limits established for drinking water supplies, and minimize the effect of water-supply development on the regional ground-water system. Other recharge-recycling schemes can also be evaluated. Estimating the recycling efficiency (of recharge ponds, trenches, spreading areas, or irrigated fields) provides a basis for predicting water-level declines, the concentration of conservative ions (conservative in the sense that no reaction other than mixing occurs to change the character of the ion being considered) in the water supply and in the regional ground-water system, and the temperature of the water supply. Hatchery development and management schemes can be chosen to optimize hatchery productivity or minimize operation costs while protecting the ground-water system.

Wisconsin↗

USGS2013

Seventy-five years of science—The U.S. Geological Survey’s Western Fisheries Research Center

As of January 2010, 75 years have elapsed since Dr. Frederic Fish initiated the pioneering research program that would evolve into today’s Western Fisheries Research Center (WFRC). Fish began his research working alone in the basement of the recently opened Fisheries Biological Laboratory on Lake Union in Seattle, Washington. WFRC’s research began under the aegis of the U.S. Fish and Wildlife Service and ends its first 75 years as part of the U.S. Geological Survey with a staff of more than 150 biologists and support personnel and a heritage of fundamental research that has made important contributions to our understanding of the biology and ecology of the economically important fish and fish populations of the Nation. Although the current staff may rarely stop to think about it, WFRC’s antecedents extend many years into the past and are intimately involved with the history of fisheries conservation in the Western United States. Thus, WFRC Director Lyman Thorsteinson asked me to write the story of this laboratory “while there are still a few of you around who were here for some of the earlier years” to document the rich history and culture of WFRC by recognizing its many famous scientists and their achievements. This historyalso would help document WFRC’s research ‘footprint’ in the Western United States and its strategic directions. Center Director Thorsteinson concluded that WFRC’s heritage told by an emeritus scientist also would add a texture of legitimacy based on personal knowledge that will all-to-soon be lost to the WFRC and to the USGS. The WFRC story is important for the future as well as for historical reasons. It describes how we got to the place we are today by documenting the origin, original mission, and our evolving role in response to the constantly changing technical information requirements of new environmental legislation and organizational decision-making. The WFRC research program owes its existence to the policy requirements of Federal conservation legislation originating with the construction of Grand Coulee Dam in 1933. The research program was shaped by laws enacted in subsequent years such as the Federal Water Pollution Control Act (1972), National Environmental Policy Act (1973), Endangered Species Act (1974), and Northwest Power Planning Act (1980), to name only a few. The WFRC has not been constrained by direct management or regulatory responsibility for a particular fishery (such as providing sustainable catch limits data to a resource management structure). Thus, WFRC has been able to concentrate on scientific pursuits and information needs required by contemporary environmental legislation. Over the years, we have pioneered in several important areas of fisheries research including the diagnoses and control of diseases in economically important fish, effects of environmental alterations on the physiological quality and survival of Pacific salmon released from federal mitigation hatcheries, applications in biotelemetry, and the bioenergetics of predator-prey interactions in the Columbia River. The WFRC of today is a widely distributed organization in the Western United States. Knowledge of the historical connections and accomplishments of our predecessors is important beyond the sense of pride and unity it instills in the WFRC family of today. For example, a discerning reader will note the evolution of WFRC’s research from a single disciplinary focus (early era—hatchery disease problems), to multiple disciplines (middle to late era—species, populations, habitats; threatened and endangered species), to the present era (multidisciplinary and with increasing process focus). For the benefit of the current WFRC staff, more emphasis has been placed on the early years rather than on the present day because people are quite naturally more familiar with the recent past than with the research done during the first decades of WFRC’s existence. By every rational measure, the WFRC has evolved into a fisheries research organization well positioned to provide the biological information needed to support the continued conservation and management of our Nation’s living aquatic natural resources. The high standard of excellence that connects WFRC’s past to our present research program provides a firm foundation on which to base the work yet to be done. In another 75 years, WFRC will undoubtedly be a very different place than it is today, but its evolution will be forever rooted in the story of the research and of the people related here. More about the diverse fisheries research projects WFRC scientists are conducting today is available at WFRC’s website: http://wfrc.usgs.gov/.

Washington↗

USGS2026

High-resolution transboundary vegetation community maps of the Sonoran and Mojave Desert ecoregion to support critical landscape conservation planning and habitat management needs

We produced a 30-m resolution binational land cover map of Bird Conservation Region 33 (BCR 33) for the U.S. North American Bird Conservation Initiative. The region covers large portions of the Sonoran and Mojave Deserts. The map can support the U.S. Fish and Wildlife Service (FWS) Migratory Bird Program’s recovery planning efforts and constitutes the first known binational land cover dataset spanning sections of the United States–Mexico border and using a consistent classification system for both countries. The mapped region includes 152 distinct land cover classes, covering a total area of 38,421,453 ha (148,345 mi 2 ), of which 13,148,345 ha (52,706 mi 2 ) are located in Mexico and 24,770,640 ha (95,639 mi 2 ) in the United States. We primarily used Landsat 8 (OLI) imagery, supplemented by limited ground surveys from two field campaigns, drone-based aerial data, and existing vegetation classification frameworks from both countries. The classification applied a data-fusion approach integrating 30-m Landsat 8 imagery, decadal phenology metrics from vegetation indices, and a random forest model trained mainly with datasets from a comprehensive national mapping project from the U.S. Geological Survey (USGS) GAP Analysis Project (GAP) and federal wildland fire agencies’ Landscape Fire and Resource Management Planning Tools (LANDFIRE) (GAP/LANDFIRE) [United States side] and the National Institute of Statistics and Geography (INEGI) [Mexico side] as well as land cover maps and opportunistic open-access and field observations. Mapping of the full BCR 33 region was carried out in two phases: 1) Phase I, the prototype map, covered a smaller portion of the transboundary area and identified 31 land cover classes, and 2) Phase II, the full BCR 33 map (refer to Figure 1), which resulted in 152 land cover classes. Using a Random Forest classifier, we achieved an overall prediction accuracy of 92% for the Phase I map and 87% for the Phase II full region map. This slight decrease can be attributed to working on a larger, more complex area with a greater number of land cover classes. No formal validation was conducted, aside from using a subset of the collected field observations and training data to assess model performance during and after training. The training sites were further verified using Google Earth (Google, 2026) imagery. Two undergraduate students who worked for over a year visually inspected imagery and open access public images to confirm each training site during model training using in-house developed, online, visual tools. A portion of this field training data was reserved for model validation, and the corresponding results are to be presented in later sections. The project developed an end-to-end, medium- and fine-resolution remote sensing–based data fusion mapping approach. This effort produced a map (Nagler et al., 2025) and the online tools to support a dynamic, live, online map for visualizing the transboundary vegetation communities in BCR 33. The toolset is currently hosted by the University of Arizona (UofA) Vegetation Index and Phenology (VIP) Lab to support FWS partners (https://vip.arizona.edu/viplab_data_explorer?LCM_BCR33). The online map is designed to allow rapid updates using new training, validation, or correction data, making it dynamic and maintainable. The approach we took established a framework for rapid updating and correction of land cover maps, as the model can be quickly retrained with new field observations, updated training data, or other sources. This enables dynamic mapping and change detection of the region’s vegetation. This framework is an advance in data fusion and crowdsourced mapping of complex, vulnerable regions, providing support to regional stakeholders and the wider user community. This transboundary map can inform the protection, conservation, and restoration of vegetation, habitat, and ecosystems, particularly for threatened and endangered species across the two nations using consistent and harmonized binational mapping systems. Beyond supporting land management decisions and stakeholders in the transboundary desert ecoregions, this BCR 33 mapping effort establishes a foundation for future rapid, low-cost, cross-border land cover mapping that can benefit and advance ecosystem management.

Arizona, Baja California, California, Nevada, Sina↗

USGS2012

Water resources of the Iroquois National Wildlife Refuge, Genesee and Orleans counties, New York 2008-2010

A 2-year study of the water resources of the Iroquois National Wildlife Refuge (Refuge) in western New York was carried out in 2009-2010 in cooperation with the U.S. Fish and Wildlife Service to assist the Refuge in the development of a 15-year Comprehensive Conservtion plan. The study focused on Oak Orchard Creek, which flows through the Refuge, the groundwater resources that underlie the Refuge, and the possible changes to these resources related to the potential development of a bedrock quarry along the northern side of the Refuge. Oak Orchard Creek was monitored seasonally for flow and water quality; four tributary streams, which flowed only during early spring, also were monitored. A continuous streamgage was operated on Oak Orchard Creek, just north of the Refuge at Harrison Road. Four bedrock wells were drilled within the Refuge to determine the type and thickness of unconsolidated glacial sediments and to characterize the thickness and type of bedrock units beneath the Refuge, primarily the Lockport Dolomite. Water levels were monitored in 17 wells within and adjacent to the Refuge and water-quality samples were collected from 11 wells and 6 springs and analyzed for physical properties, nutrients, major ions, and trace metals. Flow in Oak Orchard Creek is from two different sources. During spring runoff, flow from the Onondaga Limestone Escarpment, several miles south of the Refuge, supplements surface-water runoff and groundwater discharge from the Salina Group to the south and east of the Refuge. Flow to Oak Orchard Creek also comes from surface-water runoff from the Lockport Dolomite Escarpment, north of the Refuge, and from groundwater discharging from the Lockport Dolomite and unconsolidated deposits that overlie the Lockport Dolomite. During the summer and fall low-flow period, only small quantities of groundwater flow from the Salina shales and Lockport Dolomite bedrock and the unconsolidated sediments that overlie them; most of this flow is lost to wetland evapotranspiration, and the remainder enters Oak Orchard Creek. Water quality in the Oak Orchard Creek is affected not only by these groundwater sources but also by surface runoff from agricultural areas and the New York State Wildlife Management Area east of the Refuge. Based on the results of the drilling program, the Lockport Dolomite underlies nearly all the Refuge. The Refuge wetlands lie within a bedrock trough between the Lockport Dolomite and Onondaga Limestone Escarpments, to the north and south, respectively. This bedrock trough was filled with mostly fine-grained sediments when Glacial Lake Tonawanda was present following the last period of glaciation. These fine-grained sediments became the substrate on which the wetlands were formed along Oak Orchard Creek and nearby Tonawanda Creek, to the south and west. Water quality in the unconsolidated and bedrock aquifers is variable; poor quality water (sulfide-rich "black water") generally is present south of Oak Orchard Creek and better quality water to the north where the Lockport Dolomite is close to the land surface. A set of springs, the Oak Orchard Acid Springs, is present within the Refuge; the springs are considered unique in New York State because of their naturally low pH (approximately 2.0) and their continual discharge of natural gas. The potential development of a bedrock quarry in the Lockport Dolomite bedrock along the northern border of the Refuge may affect the nearby Refuge wetlands. The extent of drawdown needed to actively quarry the bedrock could change the local hydrology and affect groundwater-flow directions and rates, primarily in the Lockport Dolomite bedrock and possibly the Oak Orchard Acid Springs area, farther to the south. The effect on the volume of flow in Oak Orchard Creek would probably be minimal as a result of the poor interaction between the surface-water and the groundwater systems. Of greater potential effect will be the possible change in the quality of water flowing into the Refuge from the discharge of groundwater during dewatering operations at the quarry; this discharge will flow into the northern part of the Refuge and affect the quantity and quality of wetland areas downstream from the quarry discharge. These changes may affect wetland management activities because of the potential for poorquality water to affect the ecology of the wetlands and the wildlife that use these wetlands.

New York↗

USGS2018

Hydrologic assessment of the Edwin B. Forsythe National Wildlife Refuge

The Edwin B. Forsythe National Wildlife Refuge (hereafter Forsythe refuge or the refuge) is situated along the central New Jersey coast and provides a mixture of freshwater and saltwater habitats for numerous bird, wildlife, and plant species. Little data and information were previously available regarding the freshwater dynamics that support the refuge’s ecosystems. In cooperation with the U.S. Fish and Wildlife Service, the U.S. Geological Survey conducted an assessment of the hydrologic resources and processes in the refuge and surrounding areas to provide baseline information for evaluating restoration projects and future changes in the hydrologic system associated with climate change and other anthropogenic stressors. During spring 2015, water levels were measured at groundwater and surface-water sites in and near the Forsythe refuge. These water-level measurements, along with surface-water elevations obtained from digital elevation models, were used to construct water-table-elevation and depth-to-water maps of the refuge and surrounding areas. Water-table elevations in the refuge ranged from sea level to approximately 65 feet above sea level; in most of the refuge, the water-table elevation was within 3 feet of sea level. The water-table-elevation map indicates that the direction of shallow groundwater flow at the regional scale is generally from west to east (much of it from the northwest to the southeast), and groundwater moves downgradient from the uplands toward major groundwater discharge areas consisting of coastal streams and wetlands. The depth to water is estimated to be less than 2 feet for approximately 86 percent of the refuge, which coincides closely with the percentage of wetland area in the refuge. Depth to water in excess of 20 feet below land surface is limited to higher elevation areas of the refuge. Streamflow data collected at continuous-record streamgages and partial-record stations within the Mullica-Toms Basin were summarized. Hydrograph separation of streamflow data for eight streamgages (2004–13) reveals that base flow accounts for 68–94 percent of streamflow in basins upstream from the refuge. The high base-flow inputs underscore the importance of groundwater as a source of freshwater that supports both the streams that flow into the refuge and the hydroecology of the contributing basins. Mean annual flow typically ranged from 1.7 to 2.1 cubic feet per second per square mile at the streamgages (2004–13) and between 1.2 and 2.3 cubic feet per second per square mile at the partial-record stations (1965–2015) but was notably greater or lower than these ranges at several stations. Mean annual water budgets were estimated for multiple regions of the refuge for 2004–13 using data compiled from nearby meteorological stations and groundwater flows derived from previously calibrated groundwater-flow models. Precipitation, groundwater recharge, and evapotranspiration were estimated from available data; direct runoff was calculated as the residual component of the water balance. Groundwater recharge rates were greatest in the upland-dominated areas of the refuge with estimates of 14.4 to 18.9 inches per year, which are equivalent to 30 to 40 percent of precipitation. Groundwater recharge rates were nearly zero in the central coastal areas because these areas are major groundwater discharge zones, the water table is near land surface, the subsurface is close to saturation and cannot accept much recharge, and much of the area is underlain by thick marsh deposits likely with low permeability. Estimates of evapotranspiration varied from about 26 inches per year in the upland-dominated areas to more than 35 inches per year in the coastal wetlands, equivalent to 55–79 percent of mean annual precipitation, indicating that it is a major component of the hydrodynamics of the Forsythe refuge. On the basis of output from previously calibrated groundwater-flow models, nearly all of the groundwater exiting the surficial aquifer system in the central coastal areas of the refuge is discharged to wetlands, which highlights the importance of groundwater discharge in supporting the ecosystems of the Forsythe refuge. In the central coastal areas, horizontal flow contributes more than 90 percent of the groundwater flow to the surficial system, indicating that the upbasin areas are a substantial source of water that ultimately discharges to streams and wetlands in the refuge.

New Jersey↗

USGS2021

Preliminary geohydrologic assessment of Buenos Aires National Wildlife Refuge, Altar Valley, southeastern Arizona

The Buenos Aires National Wildlife Refuge is located in the southern part of Altar Valley, southwest of Tucson in southeastern Arizona. The primary water-supply well at the Buenos Aires National Wildlife Refuge has experienced a two-decade decrease in groundwater levels in the well, as have other wells in the southern part of Altar Valley. In part to understand this trend, a study was undertaken by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to summarize what is known about the geohydrologic system on the refuge and analyze groundwater-level trends and precipitation-groundwater correlations. In addition, available data were compiled where possible on the climate, land cover, soils, geology, and hydrology to provide a foundation for future modeling of the system. Altar Valley is a sedimentary basin bounded by a mixture of Paleozoic to Tertiary sedimentary, volcanic, granitic, and metamorphic rocks. The valley fill is undifferentiated Tertiary to Quaternary sediments underlain by middle Miocene to Pliocene rocks that consist of moderately to strongly consolidated conglomerate and sandstone. Surface water, when present in the predominantly ephemeral streams of the valley, flows from south to north. Arivaca Creek has a cienega (or wetland) where groundwater surfaces before it flows as a short perennial reach out of Arivaca Basin. Groundwater maps compiled between 1934 and 2016 showed groundwater flowing from south to north. Before the 1980s, temporal patterns of groundwater levels in wells in Altar Valley varied substantially from one well to another. In the mid-1980s, comparatively high levels of precipitation occurred: the 1980s median value was 15.3 inches, whereas the median for the period of record was 13.2 inches. In addition, apparently corresponding groundwater level increases were seen in nearly all wells studied. After this initial increase, two different groundwater-level trends began to be observed in two spatially distinct sets of wells: in the northern part, groundwater levels were relatively steady, whereas in the southern part, groundwater levels declined from 10 to 20 feet between 1990 and 2019. Annual groundwater pumpage declined substantially in the northern part of the valley beginning in the early 1980s, but it began to increase again in the 1990s. Pumpage in the southern part has remained low and relatively steady compared to the northern part. Although the precise reasons for the declining groundwater levels in the southern part remain unclear, groundwater levels may be affected by factors such as climate cycles, long-term drought, and temperature-induced declines in recharge, resulting in increased evapotranspiration. Preliminary analyses of two wells, one selected from each part of the valley, using linear regression and lag correlation to investigate correlation between annual precipitation and groundwater levels, showed a maximum correlation at a lag of about 17 years in the southern part of the valley and about 25 years in the northern part, indicating that, although variable sources and traveltimes of recharged water may be needed to propagate to each location, the strongest correlation at each well is with precipitation that was recharged 17 and 25 years prior to the groundwater response in that well. Assuming a constant flow of groundwater from the southern to the northern part of the valley, a decrease in recharge is expected to lead to a decrease in aquifer storage. As to the comparatively stable groundwater levels in the northern part, pumpage is still only about one-half what it was in the early 1980s, even though pumpage has increased there since the 1990s. Water levels in most wells in the northern part were drawn down prior to the decrease in pumping in the early 1980s, possibly owing to a combination of pumping and the nearly 20-year midcentury drought that occurred between 1940 and 1960. Water levels were in the process of recovering when the increase in pumping occurred in the 1990s. Because the water levels were recovering (increasing) instead of remaining static, the increased pumping may have only limited the recovery rather than causing a decrease in water levels, as a new quasi-equilibrium state may have been reached. Additional possible causes for the stable groundwater levels include (1) upgradient aquifer transmissivity that was high enough to offset pumping, (2) a low-permeability barrier, such as bedrock or clay, at the north end of the valley that caused groundwater pooling, (3) higher lateral inflow of groundwater in the northern part of the valley, (4) a delay in the effect of storage declines propagating from the south, or (5) some combination thereof.

Arizona↗

USGS2011

Population estimates and monitoring guidelines for endangered Laysan Teal, Anas Laysanensis, at Midway Atoll: Pilot study results 2008-2010.

Accurate estimates of population size are often crucial to determining status and planning recovery of endangered species. The ability to detect trends in survival and population size over time enables conservation managers to make effective decisions for species and refuge management. During 2004–2007, the translocated population of endangered Laysan Teal (Anas laysanensis; also Laysan Duck) was fitted with radio transmitters providing known (―gold standard‖) measures of survival and reproduction. However, as the population grew, statistically rigorous monitoring protocols were needed that were less labor intensive than radio telemetry. A population die-off and alarmingly high number of carcasses (181) were recorded during a botulism epizootic in August–October 2008, which further reinforced the need for effective monitoring protocols since this endangered species is vulnerable to catastrophic population declines. In fall 2008, we initiated a pilot study using standardized surveys with uniquely marked birds to monitor abundance and estimate the population growth rate of the reintroduced Laysan Teal. Since few birds carried marks (leg bands) after the 2008 botulism die-off (only about 15% of the population), and standardized surveys were not yet implemented, the magnitude of the die-off on the population size was unknown. To learn more about this endangered species' status and develop monitoring protocols useful to refuge managers and recovery planners in the U.S. Fish and Wildlife Service (USFWS), we marked (banded) 252 new Laysan Teal for this pilot project. With skilled refuge staff and trained volunteers, we conducted counts of marked, unmarked, and unknown birds during bimonthly surveys from Oct 2008 to Jan 2010. We recorded the identities of marked birds observed, recovered carcasses, and then used the last date a bird was detected alive and the median resight frequency to conclude if a bird was likely to be alive on a given survey date. Using mark-resight data and individual resight frequencies, we produced a series of abundance estimates from surveys that met accuracy criteria and approached ―closed population‖ assumptions. Since only one year of standardized, atoll-wide surveys were conducted, we analyzed data selected from multiple surveys using Lincoln-Petersen (LP) estimates instead of multi-year likelihood estimators. We adjusted surveys to account for unknown birds (e.g., swimming birds), temporary band loss, and described the frequency of double counting. Double counting is an important consideration in the population estimate because we found a maximum of 13% of marked birds were counted multiple times during a survey. These survey protocols allowed us to estimate the species' post-fledging population (combined adults and juveniles), and the methods are comparable to those used on Laysan Island. The Laysan Teal population increased 91% from 247 (95% CI, 233–260) in 2007 to 439–508 in early 2010. There was no change from 2009 to 2010 indicating that there was no population growth, however, our 2010 estimate should be considered preliminary since only one month of 2010 resight data was used. We compared a series of direct counts to their corresponding population estimates during 2008–2009 to evaluate if counts could serve as an unbiased ―index‖ of population abundance. There was a moderate correlation between abundance estimates and total birds counted (r 2 = 0.51) during resight surveys but a low correlation with all-wetland counts (r 2 = 0.02). This indicated that using direct all-wetland counts to predict abundance would result in confidence intervals on the order of ± 200 birds, which is equal to 50% of the estimate. With such large confidence intervals, it would be unlikely to detect annual changes in abundance or determine the magnitude of a catastrophic decline. To improve the Laysan Teal population estimates, we recommend changes to the monitoring protocol. Additional years of data are needed to quantify inter-annual seasonal detection probabilities, which may allow the use of standardized direct counts as an unbiased index of population size. Survey protocols should be enhanced through frequent resights, regular survey intervals, and determining reliable standards to detect catastrophic declines and annual changes in adult abundance. In late 2009 to early 2010, 68% of the population was marked with unique color band combinations. This allowed for potentially accurate adult population estimates and survival estimates without the need to mark new birds in 2010, 2011, and possibly 2012. However, efforts should be made to replace worn or illegible bands so birds can be identified in future surveys. It would be valuable to develop more sophisticated population size and survival models using Program MARK, a state-of-the-art software package which uses likelihood models to analyze mark-recapture data. This would allow for more reliable adult population and survival estimates to compare with the ―source‖ Laysan Teal population on Laysan Island. These models will require additional years of resight data (> 1 year) and, in some cases, an intensive annual effort of marking and recapture. Because data indicate standardized all-wetland counts are a poor index of abundance, monitoring efforts could be improved by expanding resight surveys to include all wetlands, discontinuing the all-wetland counts, and reallocating some of the wetland count effort to collect additional opportunistic resights. Approximately two years of additional bimonthly surveys are needed to validate the direct count as an appropriate index of population abundance. Additional years of individual resight data will allow estimates of adult population size, as specified in recovery criteria, and to track species population dynamics at Midway Atoll.

Technical Report↗

USGS1987

Results of a workshop concerning assessment of the functions of bottomland hardwoods

The U.S. Environmental Protection Agency (EPA) is authorized under Section 404 of the Clean Water Act (33 U.S.C. 1344) to participate in the regulation of the discharge of dredged or fill material into waters of the United States. This regulatory authority is exercised in partnership with the U.S. Army Corps of Engineers, which has responsibility for permit issuance, and in consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service. Through amendments to the original statute, a series of legal actions and court decisions, and the development of operating guidance among the responsible agencies, Section 404 has evolved into the primary mechanism afforded Federal authorities for the protection of wetlands. EPA recognizes the importance of wetlands in achieving the goals of the Clean Water Act, which are to protect and maintain the chemical, physical, and biological integrity of the Nation’s waters. EPA Administrator Lee Thomas has identified wetlands protection as among the highest of Agency priorities. EPA recognizes that bottomland hardwood (BLH) wetlands have vital and unique attributes that, if lost, would severely impact the physical, chemical, and biological integrity of the Nation's waters. As part of a broad program to better protect the Nation's wetlands, EPA has therefore identified bottomland hardwood wetlands as a priority resource requiring special attention on a national basis. Recognizing the importance of implementing an effective, nationally consistent, and scientifically defensible regulatory program, EPA, in October 1984, issued Interim Operating Guidance to its field personnel for implementing the Section 404 regulatory program in bottomland hardwood wetlands. With the goal of improving and finalizing that guidance, EPA is sponsoring a series of workshops designed to answer key questions concerning BLH wetlands, based on the best scientific and technical information currently available. The first two workshops were directed toward summarizing existing scientific and technical knowledge concerning the functions of BLH ecosystems, the characteristics that are important to each function, and the impact of various development activities on those characteristics. The first workshop, which was held in St. Francisville, Louisiana, in December, 1984, examined a wetland zonation concept as a framework for gaining a greater understanding of BLH structure and function. The workshop set out to determine whether characterization of BLH resources as a series of relatively distinct zones, defined by concomitant variation in hydrologic regime, soils, and vegetation, might provide the basis for a useful and scientifically sound regulatory framework. For examp1e, if certain zones are of particular importance to one or more wetland functions that the Clean Water Act was intended to protect, then the zonation concept might be useful from the perspective of how various activities should be regulated. Discussions during the first workshop, however, indicated that the zonation concept provides, at best, only an incomplete picture of the structure and function of BLH ecosystems. In many cases, BLH functions are not limited to or closely correlated with particular zones and, furthermore, many factors other than zone are important determinants of BLH functions. With these responses in mind, the second workshop, held at Lake Lanier, Georgia, in July, 1985, was designed to elicit information on two questions. First, if zones are not an adequate framework for understanding the functions of BLH systems, what characteristics (predictors) can be used to assess the extent to which a particular site performs these functions? And second, what are the impacts of various development activities that often occur in BLH ecosystems on those characteristics and thus on the functions themselves? At the second workshop, individual workgroups dealing with particular subject areas (e.g., hydrology, water quality, fisheries, wildlife, ecosystem processes, and cultural/recreational/economic resources) were able to identify site characteristics that are important determinants of the performance of various functions. For example, the Hydrology Workgroup identified flood storage as one of three major hydrologic functions that BLH ecosystems perform. The workgroup then identified the most important characteristic (e.g., surface area of the site, soil saturation, and others) that determine flood storage and the likely impact of several common activities (e.g., conversion to soybean production and levee construction) on these characteristics. Some of the workgroups also provided estimates of the aggregate impact of activities, acting through all of the characteristics, on certain functions. The workgroups also identified key characteristics that could be used to identify high-value wetlands for various functions. In addition, the workgroups pointed out a number of topics needing further examination and discussion. First, all of the workgroups identified the need to develop the technical basis and information sources to address the problem of cumulative impacts in the regulatory process. Second, most of the workgroups noted the important of contextual variables in assessing the function of a particular site. For example, the location of a BLH site in relationship to other tracts of habitat is an important variable for many wildlife species. Similarly, the extent to which a site retains or transforms contaminants is depended not only on the characteristics of the site, but also on its position in a watershed relative to contaminant inputs. And finally, several of the workgroups pointed out that assessing the impact of an activity on a function is not as simple as "adding up" the impact on individual characteristics, but may depend instead on complex interactions among characteristics. Addressing these questions, as summarized in the objectives and discussions that follow, was the focus of the third workshop, the results of which are described in this report.

Report↗

USGS2016

Surface-water quality and suspended-sediment quantity and quality within the Big River Basin, southeastern Missouri, 2011-13

Missouri was the leading producer of lead in the United States—as well as the world—for more than a century. One of the lead sources is known as the Old Lead Belt, located in southeast Missouri. The primary ore mineral in the region is galena, which can be found both in surface deposits and underground as deep as 200 feet. More than 8.5 million tons of lead were produced from the Old Lead Belt before operations ceased in 1972. Although active lead mining has ended, the effects of mining activities still remain in the form of large mine waste piles on the landscape typically near tributaries and the main stem of the Big River, which drains the Old Lead Belt. Six large mine waste piles encompassing more than 2,800 acres, exist within the Big River Basin. These six mine waste piles have been an available source of trace element-rich suspended sediments transported by natural erosional processes downstream into the Big River. A study was performed by the U.S. Geological Survey in cooperation with U.S. Environmental Protection Agency, Region 7, to calculate and characterize suspended-sediment quantity and quality within the Big River basin after reclamation of the mine waste piles ended in 2012. Streamflow and suspended sediments were quantified and sampled at two locations along a 68-mile reach of the Big River between Bonne Terre and Byrnes Mill, Missouri. The results will help regulatory agencies, such as the U.S. Environmental Protection Agency and U.S. Fish and Wildlife Service, determine impaired reaches and ecosystems for remedial and restoration efforts. Continuous stream stage, water temperature, and turbidity, and discrete suspended-sediment concentration data were collected at the two sites between October 2011 and September 2013. Suspended-sediment samples were collected during various hydrologic conditions to develop a regression model between discrete suspended-sediment concentration and continuous turbidity. Suspended sediments collected during stormflow events were analyzed for concentrations of trace elements such as barium, cadmium, lead, and zinc within two sediment size fractions. Event loads and annual loads of suspended sediment and select trace elements in suspended sediments also were calculated. Suspended-sediment loads computed by the regression model increased downstream from about 201,000 tons at the upstream site to about 355,000 tons at the downstream site during the study period. Stormflow-event-based (hereinafter referred to as “event-based”) suspended-sediment loads ranged from 180 to 32,000 tons at the upstream sampling site and 390 to 53,000 tons at the downstream site along the Big River. Although only seven stormflow events at the upstream site and six at the downstream site were sampled, the event-based suspended-sediment loads accounted for nearly 30 percent of the total suspended-sediment loads computed at both sites, indicating most of the suspended sediment transported through the Big River occurs during higher streamflows. Sediment quality guidelines, known as the threshold effect concentration and the probable effect concentration, used to assess toxicity of trace-element concentrations in sediments were compared to the cadmium, lead, and zinc concentrations in suspended sediment samples collected during stormflow events. All concentrations of cadmium, lead, and zinc in event-based suspended sediment samples exceeded the threshold and probable effect concentrations. Lead and zinc concentrations in the sediment size fraction less than 0.063 millimeters also exceeded the toxic effect threshold, above which sediment is considered to be heavily polluted causing adverse effects on sediment-dwelling organisms. Concentrations of cadmium and zinc in event-based suspended sediment samples were notably higher in samples from the upstream site than samples from the downstream site, indicating the sources of sediments enriched in these trace elements decrease in the downstream area of the watershed. The reduction in concentration of cadmium and zinc could be from dissolution of the constituents during transport or possibly a decrease in downstream source material. The lead concentration exceedance of the probable effects concentration as well as the threshold effects concentration indicates that lead-rich suspended sediments in the fraction less than 0.063 millimeters are readily available within the Big River Basin for transport. These sediments remain in the system from historical mining, and as the reclamation of mine waste piles in the upstream area of the watershed reduce additional sediment loadings, these fine sediments may be continually released as the river scours the streambed and erodes stream banks causing the lead-rich suspended sediment to remain in a state of equilibrium. Barium concentrations in suspended-sediments were nearly twice as high in stormflow event samples collected at the downstream site as compared to samples from the upstream site. The source of barium in the Big River could be from Mineral Fork and Mill Creek, which flow through the historical barite (barium sulfate, also known as tiff) mining district in Washington County, and discharge into the Big River between the two study sites. Total trace-element loads and yields in suspended sediments were computed from the sampled events for each year in the study. The total barium loads in suspended sediments were higher for sampled events collected at the downstream site than the upstream site during both study years. Cadmium and zinc loads in suspended sediments were lower at the downstream site than the upstream site, although the decrease in total load was not substantial during the study period. Lead loads in suspended sediments were lower at the downstream site during the first study year, with a slightly higher load downstream in the second year though the increase from upstream to downstream was small. Event-based yields were higher at the upstream site, indicating that readily available sediment sources are closer to the upstream site where more mining affected areas are located. The estimates determined during large precipitation events indicate that large sources of suspended sediments with large concentrations of trace elements are still available for transport within the Big River.

Missouri↗

USGS2007

Applying radar technology to migratory bird conservation and management: Strengthening and expanding a collaborative

Executive Summary Understanding the factors affecting migratory bird and bat populations during all three phases of their life cycle—breeding, nonbreeding, and migration—is critical to species conservation planning. This includes the need for information about these species’ responses to natural challenges, as well as information about the effects of human activities and structures. Habitats and other resources critical to migrants during passage and stopover are being destroyed, degraded, and threatened by human activities. Birds and bats are also uniquely susceptible to human use of the airspace. Wind turbines, communication and power transmission towers, and other tall structures, known to cause bird and bat mortality, are being erected or proposed in increasing numbers across the country. In addition, the potential for bird/aircraft collisions poses human safety threats. Management and regulatory agencies, conservation organizations, and industry currently lack the information they need to meet their missions and statutory responsibilities. The biological data available from various radar technologies offer a unique opportunity to learn more about the spatiotemporal distribution patterns, flight characteristics, and habitat use of “aero-fauna.” Recognizing the opportunities presented by radar technologies, the U.S. Geological Survey (USGS), the U.S. Fish and Wildlife Service (USFWS), and university partners collaborated first on individual projects and then in a broader, informal “collaborative” to coordinate their radar-related research and work together to develop the suite of products needed for conservation of birds and bats. Having produced two summary documents (Sojda and others, 2005; Ruth and others, 2005), the next objective was to convene a workshop for researchers, management and regulatory agencies, and other interested parties. The focus of this initial workshop was on strengthening the existing USGS-USFWS-university partnership and expanding the “collaborative” to include new Federal agency partners. The subject matter was centered on discussing available technologies, appropriate applications, management-related needs, and ways to strengthen collaborative research and conservation efforts. The workshop opened with presentations about the history of the “radar collaborative,” a description of the workshop objectives and focuses, and a summary of resource management and regulatory needs. Scientific presentations describing current research projects or subjects followed, given by USGS scientists, as well as scientists from other Federal agencies, academia, conservation and ornithological organizations, and a private contracting firm. Presenters addressed a wide variety of management issues including siting of wind-power facilities, bird/aircraft collisions, effects of hurricanes Katrina and Rita on bird migration, bird use of Conservation Reserve Program land, defining bird migration patterns at a broad regional scale, and associating migrant birds with their stopover habitats. Presentations described a variety of radar technologies including NEXRAD weather surveillance radar, modified mobile marine radar, military tracking radar, pencil beam radar, and dual polarization radar, as well as complementary techniques and analysis methods such as acoustic monitoring, thermal imaging, artificial intelligence, and individual-based modeling. Key issues, themes, and questions identified during the open discussions that followed fell into five main categories: (1) agency needs and challenges; (2) radar technology and applications—technical questions and issues; (3) tools and resources for managers and researchers; (4) standardization of protocols; and (5) collaborative opportunities. Participants identified the following management, regulatory, or business issues facing them which may be addressed with radar technologies: tall structures; wind turbines; identification and protection of key habitats; assessment of management activities; and bird/aircraft strikes. Participants frequently expressed the need for specific information about which radar technologies are best used for answering particular questions. User groups emphasized the importance of clear, defensible scientific information on which they can base their activities. In turn, researchers emphasized their need for clearly defined, specific questions from managers so that they can design and conduct the required research. Discussions about technical issues requiring further research and collaboration included target identity, ground-truthing, linking migrants to habitat, and standardized protocols for applied research. Workshop participants identified and endorsed a series of seven action items that would promote collaboration and begin to address key issues identified at the workshop: Action Item #1 : Establish a working subgroup to address large-scale surveillance radar standardization issues. Action Item #2 : Establish a working subgroup to address small-scale radar standardization issues. Action Item #3 : Bring management and regulatory agencies together to identify the three most important information needs for each key management issue relating to radar technologies. Action Item #4 : Develop Fact Sheet(s) to provide information about radar technology applications to migratory bird and bat conservation issues. Action Item #5 : Create a “radar collaborative” Website to provide information about radar biology applications, contacts, publications, and so forth. Action Item #6 : Formalize and expand the USGS-USFWS “radar collaborative.” Action Item #7 : Advance basic research, such as target identity and validation, which will support and improve our abilities to apply radar technologies to conservation objectives. There was considerable interest in expanding the “radar collaborative” to include those agencies, organizations, and industries represented at the workshop. It was felt that the publication of the workshop proceedings, implementation of action items, and additional future meetings or workshops will be crucial in strengthening the “radar collaborative” effort and promoting the use of these valuable technologies for conserving migratory species.

Open-File Report↗

USGS2016

Accuracy assessment/validation methodology and results of 2010–11 land-cover/land-use data for Pools 13, 26, La Grange, and Open River South, Upper Mississippi River System

Introduction/Background The U.S. Geological Survey (USGS)-Upper Midwest Environmental Sciences Center (UMESC) was responsible for development of several land cover/land use (LCU) systemic datasets of the Upper Mississippi River System (UMRS). These efforts (1989 and 2000) were funded by the U.S. Army Corps of Engineers’ Upper Mississippi River Restoration Program (UMRR) Long Term Resource Monitoring (LTRM) element. Development of systemic datasets includes the acquisition, processing, and serving of high-resolution aerial photography and land cover/land use spatial datasets ( http://www.umesc.usgs.gov/data_library/land_cover_use/land_cover_use_data.html ). In 2008, the UMRR reached a collaborative agreement with the U.S. Fish and Wildlife Service-Region 3 to collect high-resolution digital imagery of the entire UMRS floodplain during 2010–11 for LTRM. The UMESC helped acquire, process, and serve this imagery, as well as produce and serve the 2010–11 LCU systemic dataset of the UMRS floodplain. Digital imagery for Pools 13, 26, La Grange, and Open River South was collected using an Applanix DSS 439 digital sensor system with a 40 millimeter lens and Color Infrared (CIR) filter. The imagery was collected at a resolution of 20 centimeters/pixel (8 inches/pixel) for Pool 13 and 40 centimeters/pixel (16 inches/pixel) for Pools 26, Open River South, and La Grange. All imagery was projected to Universal Transverse Mercator (UTM) Zone 15, North American Datum of 1983 (NAD 83). The General Wetland Vegetation Classification (GWVC) system used for mapping is hierarchical, and its 31 classes can be collapsed into broader categories using either a 15- or 7-class level. While the 1989 and 2000 LCU systemic datasets have not gone through a traditional thematic accuracy assessment (AA) in the past, nor have they undergone a validation analysis, the end products are of high quality. For each systemic dataset produced (1989, 2000, 2010–11), extensive field reconnaissance is performed before photointerpretation. The intent of this field reconnaissance is to learn, test, and verify image signatures as they relate to vegetation types. Questionable areas on the imagery are visited, and the plants or land features observed in the area are recorded for reference. This procedure verifies vegetation signatures on the imagery with those on the ground. In addition, once the photointerpretation is complete, the final LCU dataset undergoes extensive quality assurance/quality control to ensure the imagery is mapped correctly. Since the 2000 LCU systemic dataset was developed, there has been a growing interest in completing thematic AAs for the LTRM LCU spatial datasets. The objective of an AA is to measure the probability that a particular location has been assigned its correct vegetation class. An AA estimates thematic (map class) errors in the data, giving users information needed to determine data suitability for a particular application. At the same time, data producers are able to learn more about the nature of errors in the data. Thus, the two attributes of an AA are “producers’ accuracy,” which is the probability that an AA point has been mapped correctly (also referred to as an error of omission); and “users’ accuracy,” which is the probability that the map actually represents what was found on the ground (also referred to as error of commission). Producers’ and users’ accuracies can be obtained from the same set of data by using different analyses. Accuracy assessment is an extensive effort that requires seasonal field personnel and equipment, data entry, analyses, and post processing—tasks that are costly and time consuming. The geospatial team at the UMESC has suggested a validation process for understanding the accuracy of the spatial datasets, which will be tested on at least some areas of the UMRS. Validation is not a true verification of map-class type in the field; however, it can provide the user of the map with useful information that is similar to a field AA. Similar to an AA, validation involves generating random points based on the total area for each map class. However, instead of collecting field data, two or three individuals not involved with the photo-interpretative mapping separately review each of the points onscreen and record a best-fit vegetation type(s) for each site. Once the individual analyses are complete, results are joined together and a comparative analysis is performed. The objective of this initial analysis is to identify areas where the validation results were in agreement (matches) and areas where validation results were in disagreement (mismatches). The two or three individuals then perform an analysis, looking at each mismatched site, and agree upon a final validation class. (If two vegetation types at a specific site appear to be equally prevalent, the validation team is permitted to assign the site two best-fit vegetation types.) Following the validation team’s comparative analysis of vegetation assignments, the data are entered into a database and compared to the mappers’ vegetation assignments. Agreements and disagreements between the map and validation classes are identified, and a contingency table is produced. This document presents the AA processes/results for Pools 13 and La Grange, as well as the validation process/results for Pools 13 and 26 and Open River South.

Iowa, Illinois, Minnesota, Missouri, Wisconsin↗