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USGS2012

Assessment of total nitrogen and total phosphorus in selected surface water of the National Park Service Northern Colorado Plateau Network, Colorado, Utah, and Wyoming, from 1972 through 2007

Nutrients are a nationally recognized concern for water quality of streams, rivers, groundwater, and water bodies. Nutrient impairment is documented by the U.S. Environmental Protection Agency as a primary cause of degradation in lakes and reservoirs, and nutrients are related to organic enrichment and oxygen depletion, which is an important cause of degradation in streams. Recently (2011), an effort to develop State-based numeric nutrient criteria has resulted in renewed emphasis on nutrients in surface water throughout the Nation. In response to this renewed emphasis and to investigate nutrient water quality for Northern Colorado Plateau Network streams, the U.S. Geological Survey, in cooperation with the National Park Service, assessed total nitrogen and total phosphorus concentration data for 93 sites in or near 14 National Park units for the time period 1972 through 2007.

Arizona;Colorado;Idaho;New Mexico;Utah;Wyoming↗

USGS2013

Analysis of environmental setting, surface-water and groundwater data, and data gaps for the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, through 2011

The Citizen Potawatomi Nation Tribal Jurisdictional Area, consisting of approximately 960 square miles in parts of three counties in central Oklahoma, has an abundance of water resources, being underlain by three principal aquifers (alluvial/terrace, Central Oklahoma, and Vamoosa-Ada), bordered by two major rivers (North Canadian and Canadian), and has several smaller drainages. The Central Oklahoma aquifer (also referred to as the Garber-Wellington aquifer) underlies approximately 3,000 square miles in central Oklahoma in parts of Cleveland, Logan, Lincoln, Oklahoma, and Pottawatomie Counties and much of the tribal jurisdictional area. Water from these aquifers is used for municipal, industrial, commercial, agricultural, and domestic supplies. The approximately 115,000 people living in this area used an estimated 4.41 million gallons of fresh groundwater, 12.12 million gallons of fresh surface water, and 8.15 million gallons of saline groundwater per day in 2005. Approximately 8.48, 2.65, 2.24, 1.55, 0.83, and 0.81 million gallons per day of that water were used for domestic, livestock, commercial, industrial, crop irrigation, and thermoelectric purposes, respectively. Approximately one-third of the water used in 2005 was saline water produced during petroleum production. Future changes in use of freshwater in this area will be affected primarily by changes in population and agricultural practices. Future changes in saline water use will be affected substantially by changes in petroleum production. Parts of the area periodically are subject to flooding and severe droughts that can limit available water resources, particularly during summers, when water use increases and streamflows substantially decrease. Most of the area is characterized by rural types of land cover such as grassland, pasture/hay fields, and deciduous forest, which may limit negative effects on water quality by human activities because of lesser emissions of man-made chemicals on such areas than in more urbanized areas. Much of the water in the area is of good quality, though some parts of this area have water quality impaired by very hard surface water and groundwater; large chloride concentrations in some smaller streams; relatively large concentrations of nutrients and counts of fecal-indicator bacteria in the North Canadian River; and chloride, iron, manganese, and uranium concentrations that exceed primary or secondary drinking-water standards in water samples collected from small numbers of wells. Substantial amounts of hydrologic and water-quality data have been collected in much of this area, but there are gaps in those data caused by relatively few streamflow-gaging stations, uneven distribution of surface-water quality sampling sites, lack of surface-water quality sampling at high-flow and low-flow conditions, and lack of a regularly measured and sampled groundwater network. This report summarizes existing water-use, climatic, geographic, hydrologic, and water-quality data and describes several means of filling gaps in hydrologic data for this area.

Oklahoma↗

USGS2013

Regional bankfull-channel dimensions of non-urban wadeable streams in Indiana

During floods, damage to properties and community infrastructure may result from inundation and the processes of erosion. The damages imparted by erosion are collectively termed the fluvial erosion hazard (FEH), and the Indiana Silver Jackets Multi-agency Hazard Mitigation Taskforce is supporting a program to build tools that will assist Indiana property owners and communities with FEH-mitigation efforts. As part of that program, regional channel-dimension relations are identified for non-urban wadeable streams in Indiana. With a site-selection process that targeted the three largest physiographic regions of the state, field work was completed to measure channel-dimension and channel-geometry characteristics across Indiana. In total, 82 sites were identified for data collection; 25 in the Northern Moraine and Lake region, 31 in the Central Till Plain region, and 26 in the Southern Hills and Lowlands region. Following well established methods, for each data-collection site, effort was applied to identify bankfull stage, determine bankfull-channel dimensions, and document channel-geometry characteristics that allowed for determinations of channel classification. In this report, regional bankfull-channel dimension results are presented as a combination of plots and regression equations that identify the relations between drainage area and the bankfull-channel dimensions of width, mean depth, and cross-sectional area. This investigation found that the channel-dimension data support independent relations for each of the three physiographic regions noted above. Furthermore, these relations show that, for any given drainage area, northern Indiana channels have the smallest predicted dimensions, southern Indiana channels have the largest predicted dimensions, and central Indiana channels are intermediate in their predicted dimensions. When considering the suite of variables that influence bankfull-channel dimensions, it appears that contrasting runoff characteristics between the three physiographic regions may explain much of the inequality observed in the measured channel dimensions. While this investigation targeted non-urban wadeable streams in Indiana, site conditions prevented data collection in some areas. Therefore, application of the results of this study always should include knowledge gained from local observations.

Indiana↗

USGS2017

Groundwater discharge to the Mississippi River and groundwater balances for the Interstate 94 Corridor surficial aquifer, Clearwater to Elk River, Minnesota, 2012–14

The Interstate 94 Corridor has been identified as 1 of 16 Minnesota groundwater areas of concern because of its limited available groundwater resources. The U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources, completed six seasonal and annual groundwater balances for parts of the Interstate 94 Corridor surficial aquifer to better understand its long-term (next several decades) sustainability. A high-precision Mississippi River groundwater discharge measurement of 5.23 cubic feet per second per mile was completed at low-flow conditions to better inform these groundwater balances. The recharge calculation methods RISE program and Soil-Water-Balance model were used to inform the groundwater balances. For the RISE-derived recharge estimates, the range was from 3.30 to 11.91 inches per year; for the SWB-derived recharge estimates, the range was from 5.23 to 17.06 inches per year. Calculated groundwater discharges ranged from 1.45 to 5.06 cubic feet per second per mile, a ratio of 27.7 to 96.4 percent of the measured groundwater discharge. Ratios of groundwater pumping to total recharge ranged from 8.6 to 97.2 percent, with the longer-term groundwater balances ranging from 12.9 to 19 percent. Overall, this study focused on the surficial aquifer system and its interactions with the Mississippi River. During the study period (October 1, 2012, through November 30, 2014), six synoptic measurements, along with continuous groundwater hydrographs, rainfall records, and a compilation of the pertinent irrigation data, establishes the framework for future groundwater modeling efforts.

Minnesota↗

USGS2018

Comparison of U.S. Geological Survey and Bureau of Reclamation water-use reporting in the Colorado River Basin

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State, and Federal entities develop, compile, and report water-use data, which can lead to confusing or conflicting information. This report was authored jointly by the U.S. Geological Survey (USGS) and Bureau of Reclamation (Reclamation) to compare and contrast the two agencies’ water-use information programs in the Colorado River Basin. The report also describes the legal drivers for each program, clarifies confusing terminology, compares the methods used, and contrasts the information reported by each agency. This detailed comparison demonstrates that these two Federal agencies have different missions, different programmatic drivers, and different user communities, all of which lead to different approaches to water-use data collection, analysis, and reporting. This report highlights those differences and explains why the USGS and Reclamation programs exist and how the data serve different user communities. Even though the two water-use programs are different by design and purpose, the program comparison presented in this report has identified opportunities for closer coordination and sharing of information between the USGS and Reclamation, as well as program components where agency collaboration can improve water-use estimate methodologies. This comparison effort emphasizes that it is incumbent upon each agency to clearly define the meaning of the terms used and the appropriate application of the reported information to avoid confusion or the accidental misuse of the information. An additional benefit of this comparison effort is the formation of a joint USGS/Reclamation water-use team that will continue to investigate opportunities to expand and coordinate future water-use data compilation and reporting.

Arizona, Colorado, New Mexico, Utah, Wyoming↗

USGS2019

Hydrologic study at Farm Creek Marsh, Dorchester County, Maryland, from April 2015 to April 2016

In 2015, the U.S. Geological Survey began a 1-year hydrologic study to investigate the extent and cause of inundation at Farm Creek Marsh, in Dorchester County, Maryland. In combination with a tide and precipitation gage, a representative section of the marsh was instrumented with surface-water monitors and shallow groundwater piezometers to capture the spatial and temporal extent of inundation. In addition, water-quality data (major ions and nutrients) were collected to help discern the cause of inundation. Results indicate that during the year-long study, all sites were periodically inundated, ranging from a total of 108 days to the entire study period of 353 days. The depth of inundation was typically between 0 and 0.2 feet (ft) (above land surface), with the exception of large storm events. Less than 0.5 ft of elevation was the difference between a site being inundated during the entire study period of 353 days and a site being inundated for 36 consecutive days out of 108 total days of inundation during the study period. Water-quality data showed a large difference in pH between marsh surface water (6.1 to 6.9 standard pH units) and shallow groundwater (3.0 to 3.6 standard pH units), with differences also observed in concentrations of silica, iron, manganese, and potassium. Collectively, the combination of water-quality, hydrologic, and soils data indicate that inundation is caused by tide and storm events rather than groundwater discharge.

Maryland↗

USGS2019

Transmissivity and geophysical data for selected wells at and near the Idaho National Laboratory, Idaho, 2017–18

The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, conducted aquifer tests during 2017–18 on 101 wells at and near the Idaho National Laboratory, Idaho, to define the hydraulic characteristics for individual wells. These were short-duration aquifer tests, conducted with a limited number of observations during routine sampling. Pumped intervals (water columns) for individual wells ranged from 12 to 790 feet (ft). Semi-constant discharge rates during aquifer testing ranged from 1 to 45 gallons per minute, water-level response to pumping ranged from no observed drawdown to 52.4 ft, and length of aquifer tests for individual wells ranged from 10 to 160 minutes. Individual well data were analyzed to estimate the capacity of the well to produce water (specific capacity) and to estimate values for transmissivity. Estimates of specific capacity for individual wells ranged from less than 1.0 to greater than (>) 3.0 × 10 3 gallons per minute per foot; estimates of transmissivity for individual wells ranged from 2.0 to >5.4 x 10 5 feet squared per day. Geophysical log data, well construction information, and general geology for individual wells were presented and included in this report. Basic hydrogeologic features for individual wells were described, along with a composite of natural gamma, neutron, gamma-gamma dual density, and acoustic televiewer data (when available). The geophysical and geologic data were used to suggest the location and thickness of sediment layers along with fractured and dense basalt areas for individual wells. Geophysical data were used to describe the general geology where geologic descriptions and (or) driller notes were not available.

Idaho↗

USGS2021

Estimating Piacenzian sea surface temperature using an alkenone-calibrated transfer function

Stationarity of environmental preferences is a primary assumption required for any paleoenvironmental reconstruction using fossil materials based upon calibration to modern organisms. Confidence in this assumption decreases the further back in time one goes, and the validity of the assumption that species temperature tolerances have not changed over time has been challenged in Pliocene studies. We use paired U K′ 37 (unsaturated ketones with 37 carbon atoms) sea surface temperature (SST) and faunal assemblage data to directly calibrate North Atlantic Piacenzian planktonic foraminifer assemblages to Piacenzian alkenone paleotemperature estimates to provide an alternative paleoceanographic reconstruction approach that does not rely on stationarity. In doing so, we extend Pliocene SST estimates to sites where only quantitative faunal assemblage data were previously available and improve the spatial resolution of the North Atlantic SST reconstruction.

Scientific Investigations Report↗

USGS2021

Factors affecting uncertainty of public supply, self-supplied domestic, irrigation, and thermoelectric water-use data, 1985–2015—Evaluation of information sources, estimation methods, and data variability

The U.S. Geological Survey (USGS) Water-Use Program is responsible for compiling and disseminating the Nation's water-use data. Working in cooperation with local, State, and Federal agencies, the USGS has collected and published national water-use estimates every 5 years, beginning in 1950. These water-use data may vary because of actual changes in water use, because of changes in estimation methods, or because of errors. Comparison and interpretation of these data is difficult without first determining the factors that contribute to data variability. This report describes factors that may affect data quality and documents ways to investigate the variability of public supply, self-supplied domestic, irrigation, and thermoelectric water-use data for the 1985–2015 compilations. The USGS produces national water-use estimates for various categories of water use for every county in the United States. Knowledge about the sources of data for county estimates is important because factors such as estimation methodology and reporting affect data uncertainty Determination of meaningful patterns and trends in the data are contingent on the use of consistent methodology throughout the period of interest. With the many ways that water-use data have been collected, assembled, and estimated, multiple factors likely contribute to data uncertainty, Data used to produce these estimates may be furnished from agencies that collect information from entities who report water use; gaps in reported data are typically estimated to achieve a comprehensive county estimate. For example, public supply and thermoelectric category data are based primarily on furnished site-specific data; whereas crop irrigation is often furnished or estimated at the county scale. Public supply deliveries for domestic use and self-supplied domestic withdrawals are most often estimated by USGS personnel using per capita use rate coefficients. Irrigation may be estimated using crop water requirements, application rates, or other soil water balance methods when furnished reported data are not available. Rates, percentages, medians, and interquartile ranges were used to investigate variability in the water-use data among States, regions, and years. The purposes of these evaluations were to (1) identify extreme values that may reflect changes in information sources, estimation methods, or errors; (2) indicate areas of variable or consistent values that are unexpected; and (3) indicate areas where values change because of local climate or other factors. Where factors are identified that contribute to data variability, such as a change in methodology, additional work could determine uncertainty because of these factors. These evaluations identified the availability of information that is needed to address data limitations. Factors such as estimation methodology affect data quality. Some updates to method codes assigned in 2015 and assignment of method codes to earlier compilation datasets for all categories would provide much needed metadata for users of the data. Improvements in data documentation describing sources of information and estimation methods and additional metadata information from agencies and entities that furnish water-use data, would enable a more complete understanding and depiction of water-use patterns and trends. Additional metadata are needed for users of the data to better understand the water-use data and interpret changes in water use across the United States and with time.

Scientific Investigations Report↗

USGS2023

Prediction of the probability of elevated nitrate concentrations at groundwater depths used for drinking-water supply in the Puget Sound basin, Washington, 2004–19

The Puget Sound basin encompasses the 13,700-square-mile area that drains to the Puget Sound and the adjacent marine waters of Washington State. Well more than 4 million people live within the basin, with numbers continuing to increase, who rely on the basin’s natural resources including groundwater. The Puget Sound Partnership was created by a Washington State statute to implement a science-based recovery of the Puget Sound to help address impacts to these resources. As part of the recovery, the partnership developed the Puget Sound Vital Signs as measures of ecosystem health that guide the assessment of progress toward Puget Sound recovery goals. The Puget Sound Partnership Leadership Council adopted a Drinking Water Vital Sign associated with human health and quality of life, recognizing certain indicators as integral to the sustainability of Puget Sound recovery efforts. One such Vital Sign indicator was the vulnerability of groundwater throughout the aquifers of the Puget Sound basin to elevated nitrate concentrations as defined by the probability of exceeding 2 milligrams/liter (mg/L) at a specific location and well depth. The U.S. Geological Survey (USGS) led the effort to characterize groundwater vulnerability. For this study, groundwater vulnerability refers to a probability with which a contaminant applied at or near the land surface can migrate to the aquifer of interest for a given set of land-use practices. Nitrate concentration data were selected for evaluation because elevated nitrate concentrations are typically caused by anthropogenic activities and have been associated with deleterious impacts on human health. To identify groundwater vulnerability to elevated nitrate concentrations, logistic regression was used to relate anthropogenic (human associated) and natural variables to the occurrence of elevated nitrate concentrations in untreated groundwater from large public water supply system wells found within the Washington State Department of Health Sentry database. Variables that were analyzed included well depth, soil hydraulic conductivity, precipitation, population density, fertilizer application amounts, and land-use types. Statistically significant models that predicted the probabilities of groundwater nitrate concentrations greater than 2 mg/L based on the predictor variables were created for the time periods 2000–04, 2005–09, 2010–14, and 2015–19. For all time periods, well depth and a measure of the abundance of urban and agricultural land over or near the well consistently helped explain the vulnerability of the well to elevated nitrate concentrations defined as a probability of exceeding 2 mg/L of nitrate. Precipitation and (or) soil hydraulic conductivity were also important predictor variables in the models. The models for each time period were used to create maps of groundwater vulnerability at 150- and 300-foot depths throughout the Puget Sound basin. As expected, the most vulnerable locations were associated with shallower well depths and increased agriculture and urban land cover. Across all four time periods, groundwater vulnerability throughout the Puget Sound was low, with probabilities of exceeding 2 mg/L concentrations of nitrate at depths at 150 and 300 feet typically less than 50 percent. Results also found a slight decrease in probabilities of elevated nitrate concentrations throughout the basin over time. More specifically, additional statistical tests found that groundwater with probabilities of less than about 60 percent declined from 2000 to 2019 and represented more than 75 percent of the modeled Puget Sound basin aquifer. Wells with greater than 60 percent probability increased over the same time period but represented only about 25 percent of the aquifer. The maps and statistical analysis presented in the study provide valuable and informative evaluation of the vulnerability of groundwater in the Puget Sound basin to elevated nitrate concentrations. The probability maps do not represent measured nitrate concentrations in groundwater, but rather they present the probability that nitrate concentrations exceed 2 mg/L. The models and predictions from this study are a viable indicator for the Puget Sound Partnership’s Healthy Human Population—Drinking Water Vital Sign. The logistic regression modeling approach presented here benefits water managers by allowing them to assess temporal trends in a range of probabilities, explore vulnerability changes as new regional land cover and anthropogenic data are generated, and distinguish vulnerabilities at different depths within the aquifer.

Washington↗

USGS2021

Chapter A6.4. Measurement of pH

The “National Field Manual for the Collection of Water-Quality Data” (NFM) provides guidelines and procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation’s surface-water and groundwater resources. This chapter, NFM A6.4, provides guidance and protocols for the measurement of pH of a water sample, which include the scientific basis of the measurement, selection and maintenance of equipment, calibration, procedures for measurement and reporting, and troubleshooting. It updates and supersedes USGS Techniques of Water-Resources Investigations, book 9, chapter A6.4, version 2.0, by G.F. Ritz and J.A. Collins. The pH of natural waters is routinely measured when water samples are collected, is often measured continually at USGS streamgages, and is a parameter regularly measured during laboratory and field experiments. The field methods for measuring pH described in this chapter are applicable to most natural waters. Before 2017, the NFM chapters were released in the USGS Techniques of Water-Resources Investigations series. Effective in 2018, new and revised NFM chapters are being released in the USGS Techniques and Methods series; this series change does not affect the content and format of the NFM. More information is in the general introduction to the NFM (USGS Techniques and Methods, book 9, chapter A0) at https://doi.org/10.3133/tm9A0 . The authoritative current versions of NFM chapters are available in the USGS Publications Warehouse at https://pubs.er.usgs.gov/ . Comments, questions, and suggestions related to the NFM can be addressed to nfm@usgs.gov .

Techniques and Methods↗

USGS2006

Digital database of recently active traces of the Hayward Fault, California

The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Hayward Fault Zone, California. The mapped traces represent the integration of the following three different types of data: (1) geomorphic expression, (2) creep (aseismic fault slip),and (3) trench exposures. This publication is a major revision of an earlier map (Lienkaemper, 1992), which both brings up to date the evidence for faulting and makes it available formatted both as a digital database for use within a geographic information system (GIS) and for broader public access interactively using widely available viewing software. The pamphlet describes in detail the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map. [Last revised Nov. 2008, a minor update for 2007 LiDAR and recent trench investigations; see version history below.]

California↗

USGS2007

High-resolution topographic, bathymetric, and oceanographic data for the Pleasure Point area, Santa Cruz County, California: 2005-2007

The County of Santa Cruz Department of Public Works and the County of Santa Cruz Redevelopment Agency requested the U.S. Geological Survey (USGS) Western Coastal and Marine Geology Team (WCMG) to provide baseline geologic and oceanographic information on the coast and inner shelf at Pleasure Point, Santa Cruz County, California. The rationale for this proposed work is a need to better understand the environmental consequences of a proposed bluff stabilization project on the beach, the nearshore and the surf at Pleasure Point, Santa Cruz County, California. To meet these information needs, the USGS-WCMG Team collected baseline scientific information on the morphology and waves at Pleasure Point. This study provided high-resolution topography of the coastal bluffs and bathymetry of the inner shelf off East Cliff Drive between 32nd Avenue and 41st Avenue. The spatial and temporal variation in waves and their breaking patterns at the study site were documented. Although this project did not actively investigate the impacts of the proposed bluff stabilization project, these data provide the baseline information required for future studies directed toward predicting the impacts of stabilization on the sea cliffs, beach and nearshore sediment profiles, natural rock reef structures, and offshore habitats and resources. They also provide a basis for calculating potential changes to wave transformations into the shore at Pleasure Point.

California↗

USGS1979

Bibliographic supplement to USGS Bulletin 1426; 1975 to June 1979

This bibliography is a supplement to U.S. Geological Survey Bulletins 1426 (Bergquist, 1976) and 1263 (Heath and Tabacchi, 1968). The titles listed result from work undertaken in cooperation with national agencies partly through technical assistance projects under the auspices of the Agency for International Development, U.S. Department of State; partly under reimbursable assistance projects with other governments on behalf of the Department of State; partly under assistance projects sponsored by international organizations; and partly under scientific exchange projects supported by U.S. agencies such as the National Science Foundation. This report includes titles published during the period 1975 through June 1979, but is not necessarily complete, as an exhaustive search was not made; however, it is being released in open file in order to make the data available to the public on an interim basis. Seven geographic regions and 71 countries are represented. A few titles published prior to 1975 have been found that are not included in Bulletins 1263 or 1426. Only reports authored solely or in part by USGS members, or jointly by USGS and counterpart staff members, are listed. The reports are listed alphabetically by author, under the appropriate country; reports of wider scope are given under the continent or geographic region, for example, Africa, Central and South America, or CENTO region. Reports not classifiable by geographic location are listed separately under the heading "General." All references to reports on water resources and hydrology were provided by J. R. Jones or R. M. Beall, USGS. The reports and maps are available only through the listed source. Copies of articles published in scientific journals or by other governments or agencies cannot be ordered from the USGS. Instructions for ordering publications of the USGS follow.

Open-File Report↗

USGS2022

Estimating allowable take for an increasing bald eagle population in the United States

Effectively managing take of wildlife resulting from human activities poses a major challenge for applied conservation. Demographic data essential to decisions regarding take are often expensive to collect and are either not available or based on limited studies for many species. Therefore, modeling approaches that efficiently integrate available information are important to improving the scientific basis for sustainable take thresholds. We used the prescribed take level (PTL) framework to estimate allowable take for bald eagles ( Haliaeetus leucocephalus ) in the conterminous United States. We developed an integrated population model (IPM) that incorporates multiple sources of information and then use the model output as the scientific basis for components of the PTL framework. Our IPM is structured to identify key parameters needed for the PTL and to quantify uncertainties in those parameters at the scale at which the United States Fish and Wildlife Service manages take. Our IPM indicated that mean survival of birds >1 year old was high and precise (0.91, 95% CI = 0.90–0.92), whereas mean survival of first-year eagles was lower and more variable (0.69, 95% CI = 0.62–0.78). We assumed that density dependence influenced recruitment by affecting the probability of breeding, which was highly imprecise and estimated to have declined from approximately 0.988 (95% CI = 0.985–0.993) to 0.66 (95% CI = 0.34–0.99) between 1994 and 2018. We sampled values from the posterior distributions of the IPM for use in the PTL and estimated that allowable take (e.g., permitted take for energy development, incidental collisions with human made structures, or removal of nests for development) ranged from approximately 12,000 to 20,000 individual eagles depending on risk tolerance and form of density dependence at the scale of the conterminous United States excluding the Southwest. Model-based thresholds for allowable take can be inaccurate if the assumptions of the underlying framework are not met, if the influence of permitted take is under-estimated, or if undetected population declines occur from other sources. Continued monitoring and use of the IPM and PTL frameworks to identify key uncertainties in bald eagle population dynamics and management of allowable take can mitigate this potential bias, especially where improved information could reduce the risk of permitting non-sustainable take.

Journal of Wildlife Management↗

USGS2011

Testing earthquake source inversion methodologies

Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They are also used to provide a rapid assessment of the severity of an earthquake and to estimate losses. However, because of uncertainties in the data, assumed fault geometry and velocity structure, and chosen rupture parameterization, it is not clear which features of these source models are robust. Improved understanding of the uncertainty and reliability of earthquake source inversions will allow the scientific community to use the robust features of kinematic inversions to more thoroughly investigate the complexity of the rupture process and to better constrain other earthquakerelated computations, such as ground motion simulations and static stress change calculations.

Eos, Transactions, American Geophysical Union↗

USGS2022

Physics-guided neural networks (PGNN): An application in lake temperature modeling

This chapter introduces a framework for combining scientific knowledge of physics-based models with neural networks to advance scientific discovery. It explains termed physics-guided neural networks (PGNN), leverages the output of physics-based model simulations along with observational features in a hybrid modeling setup to generate predictions using a neural network architecture. Data science has become an indispensable tool for knowledge discovery in the era of big data, as the volume of data continues to explode in practically every research domain. Recent advances in data science such as deep learning have been immensely successful in transforming the state-of-the-art in a number of commercial and industrial applications such as natural language translation and image classification, using billions or even trillions of data samples. Accurate water temperatures are critical to understanding contemporary change, and for predicting future thermal habitat of economically valuable fish.

Book chapter↗

USGS2001

Arctic National Wildlife Refuge, 1002 area, petroleum assessment, 1998, including economic analysis

The Alaska National Interest Lands Conservation Act (1980) established the Arctic National Wildlife Refuge (ANWR). In section 1002 of that act, Congress deferred a decision regarding future management of the 1.5-million-acre coastal plain ("1002 area") in recognition of the area’s potentially enormous oil and gas resources and its importance as wildlife habitat. A report on the resources (including petroleum) of the 1002 area was submitted in 1987 to Congress by the Department of the Interior (DOI). Since completion of that report, numerous wells have been drilled and oil fields discovered near ANWR, new geologic and geophysical data have become available, seismic processing and interpretation capabilities have improved, and the economics of North Slope oil development have changed significantly. The U.S. Geological Survey (USGS) commonly is asked to provide the Federal Government with timely scientific information in support of decisions regarding land management, environmental quality, and economic and strategic policy. To do so, the USGS must anticipate issues most likely to be the focus of policymakers in the future. Anticipating the need for scientific information and considering the decade-old perspective of the petroleum resource estimates included in the 1987 Report to Congress, the USGS has reexamined the geology of the ANWR 1002 area and has prepared a new petroleum resource assessment.

Fact Sheet↗