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USGS2011

Quality assurance and quality control of geochemical data—A primer for the research scientist

Geochemistry is a constantly expanding science. More and more, scientists are employing geochemical tools to help answer questions about the Earth and earth system processes. Scientists may assume that the responsibility of examining and assessing the quality of the geochemical data they generate is not theirs but rather that of the analytical laboratories to which their samples have been submitted. This assumption may be partially based on knowledge about internal and external quality assurance and quality control (QA/QC) programs in which analytical laboratories typically participate. Or there may be a perceived lack of time or resources to adequately examine data quality. Regardless of the reason, the lack of QA/QC protocols can lead to the generation and publication of erroneous data. Because the interpretations drawn from the data are primary products to U.S. Geological Survey (USGS) stakeholders, the consequences of publishing erroneous results can be significant. The principal investigator of a scientific study ultimately is responsible for the quality and interpretation of the project's findings, and thus must also play a role in the understanding, implementation, and presentation of QA/QC information about the data. Although occasionally ignored, QA/QC protocols apply not only to procedures in the laboratory but also in the initial planning of a research study and throughout the life of the project. Many of the tenets of developing a sound QA/QC program or protocols also parallel the core concepts of developing a good study: What is the main objective of the study? Will the methods selected provide data of enough resolution to answer the hypothesis? How should samples be collected? Are there known or unknown artifacts or contamination sources in the sampling and analysis methods? Assessing data quality requires communication between the scientists responsible for designing the study and those collecting samples, analyzing samples, treating data, and interpreting results. This primer has been developed to provide basic information and guidance about developing QA/QC protocols for geochemical studies. It is not intended to be a comprehensive guide but rather an introduction to key concepts tied to a list of relevant references for further reading. The guidelines are presented in stepwise order beginning with presampling considerations and continuing through final data interpretation. The goal of this primer is to outline basic QA/QC practices that scientists can use before, during, and after chemical analysis to ensure the validity of the data they collect with the goal of providing defendable results and conclusions.

Open-File Report↗

USGS2005

Void-Filled SRTM Digital Elevation Model of Afghanistan

EXPLANATION The purpose of this data set is to provide a single consistent elevation model to be used for national scale mapping, GIS, remote sensing applications, and natural resource assessments for Afghanistan's reconstruction. For 11 days in February of 2000, the National Aeronautics and Space Administration (NASA), the National Geospatial-Intelligence Agency ian Space Agency (ASI) flew X-band and C-band radar interferometry onboard the Space Shuttle Endeavor. The mission covered the Earth between 60?N and 57?S and will provide interferometric digital elevation models (DEMs) of approximately 80% of the Earth's land mass when processing is complete. The radar-pointing angle was approximately 55? at scene center. Ascending and descending orbital passes generated multiple interferometric data scenes for nearly all areas. Up to eight passes of data were merged to form the final processed Shuttle Radar Topography Mission (SRTM) DEMs. The effect of merging scenes averages elevation values recorded in coincident scenes and reduces, but does not completely eliminate, the amount of area with layover and terrain shadow effects. The most significant form of data processing for the Afghanistan DEM was gap-filling areas where the SRTM data contained a data void. These void areas are as a result of radar shadow, layover, standing water, and other effects of terrain as well as technical radar interferometry phase unwrapping issues. To fill these gaps, topographic contours were digitized from 1:200,000 - scale Soviet General Staff Topographic Maps which date from the middle to late 1980's. Digital contours were gridded to form elevation models for void areas and subsequently were merged with the SRTM data through GIS and image processing techniques. The data contained in this publication includes SRTM DEM quadrangles projected and clipped in geographic coordinates for the entire country. An index of all available SRTM DEM quadrangles is displayed here: Index_Geo_DD.pdf. Also included are quadrangles projected into their appropriate Universal Transverse Mercator (UTM) projection. The country of Afghanistan spans three UTM Zones: Zone 41, Zone 42, and Zone 43. Maps are stored in their respective UTM Zone projection. Indexes of all available SRTM DEM quadrangles in their respective UTM zone are displayed here: Index_UTM_Z41.pdf, Index_UTM_Z42.pdf, Index_UTM_Z43.pdf.

Data Series↗

USGS2011

Science Goals of the U.S. Department of the Interior Southeast Climate Science Center

In 2011, the U.S. Department of the Interior Southeast Climate Science Center (CSC) finalized the first draft of its goals for research needed to address the needs of natural and cultural partners for climate science in the Southeastern United States. The science themes described in this draft plan were established to address the information needs of ecoregion conservation partnerships, such as the Landscape Conservation Cooperatives (LCCs) and other regional conservation-science and resource-management partners. These themes were developed using priorities defined by partners and stakeholders in the Southeast and on a large-scale, multidisciplinary project-the Southeast Regional Assessment Project (SERAP)-developed in concert with those partners. Science products developed under these themes will provide models of potential future conditions, assessments of likely impacts, and tools that can be used to inform the conservation management decisions of LCCs and other partners. This information will be critical as managers try to anticipate and adapt to climate change. Resource managers in the Southeast are requesting this type of information, in many cases as a result of observed climate change effects. The Southeast CSC draft science plan identifies six science themes and frames the activities (tasks, with examples of recommended near-term work for each task included herein) related to each theme that are needed to achieve the objectives of the Southeast CSC.

Fact Sheet↗

USGS2021

Informing future condition scenario planning for habitat specialists of the imperiled pine rockland ecosystem of South Florida

This project evaluated habitat conditions for two species found in the imperiled pine rockland ecosystem—the Rim Rock Crowned Snake ( Tantilla oolitica ) and the Key Ring-Necked Snake ( Diadophis punctatus acricus ). The Rim Rock Crowned Snake historically occurred in eastern Miami-Dade County (hereafter, mainland) as well as throughout the Florida Keys, whereas the Key Ring-Necked Snake occurs only in lower Florida Keys (Enge et al. 2004; Mays and Enge 2016). Both species are very elusive, small (< 20 cm in length) and primarily fossorial. Pine rockland habitat is rapidly disappearing in South Florida, with < 3 percent of its original extent remaining. Saltwater intrusion from hurricanes and sea-level rise (SLR), and human development pose the greatest threats to the longevity of this ecosystem which, in turn, places species that are endemic to this unique habitat at risk of extinction. The Rim Rock Crowned Snake and the Key Ringed-Necked Snake are being considered for listing by the U.S. Fish and Wildlife Service (USFWS). To aid the agency’s decision, it must be able to forecast species’ responses to potential future environmental conditions, as well as to different conservation and management actions. Yet, the information needed to complete these forecasts—such as population trends, life history traits, habitat use, and future land use and climate conditions—is often lacking for most rare species. This is especially problematic for assessments of species resiliency to changes in climate and land use. When these types of data are lacking, information on habitat quality can be used to help determine how a species will respond to change. First, this project gathered current and historical records for both species from various sources such as museum specimens, inventories, and other personal account. Then, we identified potential future changes in habitat that could result from different management actions, such as habitat acquisition or restoration, and environmental conditions, such as changes in the frequency and intensity of tropical storms and rates of SLR. Researchers then explored the potential impacts of these habitat condition changes on the Rim Rock Crowned Snake and Key Ring-Necked Snake. This information can be used by the USFWS to help make decisions about the need to protect these species under the Endangered Species Act and could inform the conservation, management, and recovery of other at-risk species found in the pine rockland ecosystem. This work supports the Secretary of Interior’s priority to create a conservation stewardship legacy by using science to identify best practices to manage land and water resource and adapt to changes in the environment.

Florida↗

USGS2024

Understanding and forecasting potential recruitment of Lake Michigan fishes by modeling growth and survival of larval stages with coupled climate, biophysical, and bioenergetics models

Individual adult fish can produce huge numbers of small offspring, but most die in the first weeks of life. Environmental changes that lead to even small changes in early life survival can have a disproportionate impact on the number of fish that survive and ultimately support fisheries. Lake Michigan supports valuable recreational and commercial fisheries that can fluctuate with how well fish survive in early life. Statistical models have revealed linkages between survival and climate characteristics, such as water temperature, but the exact mechanisms remain unclear and how future climate will affect the survival of young fish is highly uncertain. We integrated a series of models to investigate how climate variability may explain historical variation in the survival of young alewife and yellow perch, two fish populations that support key fisheries either directly or indirectly, while also projecting their future survival in the mid-21st century under different scenarios informed by consultation with fishery managers. Our model results revealed how spring and summer water temperatures in Lake Michigan can affect the environment in which young alewife and yellow perch grow and survive. Specifically, in years when lake warming is rapid, young fish are more likely to be transported from their natal, productive, nearshore environments to cooler and less productive offshore environments, unless adults also spawn earlier in these warm years. Furthermore, model predictions of prey abundance for young fish in the mid-21st century indicate less favorable conditions for growth and survival compared to predictions based solely on warming temperatures. With completion of the final products in the coming year, including predicted growth and survival of young fish under different future scenarios, fishery managers will have more information to share with stakeholders regarding how expectations may need to be modified regarding alewife and yellow perch productivity.

Lake Michigan↗

USGS1991

Review of water demand and water utilization studies for the Provo River drainage basin, and review of a study of the effects of the proposed Jordanelle Reservoir on seepage to underground mines, Bonneville unit of the central Utah project

Problem: Questions have been raised concerning the adequacy of available water to fulfill the needs of storage, exchanges, diversions, and instream flows, pursuant to existing water rights in the Provo River drainage basin part of the Bonneville Unit. Also, concern has been expressed about the potential for seepage of water from Jordanelle Reservoir to underground mines. The Utah Congressional Delegation requested that the U.S. Geological Survey (USGS) review the results of analyses performed by and for the USBR. Purpose and Scope: The purpose of this report is to present the results of the USGS review of (1) the hydrologic data, techniques, and model used by the USBR in their hydrologic analyses of the Provo River drainage basin and (2) the results of a study of the potential for seepage from the Jordanelle Reservoir to nearby underground mines. The USGS reviewed USBR-supplied water demands, water utilization studies, and models of seepage from Jordanelle Reservoir. The USBR estimated that about 90 percent of the water supply for Jordanelle Reservoir will be water from Strawberry Reservoir exchanged for water from the Provo River stored in Utah Lake. If the Utah State Engineer allows the USBR to claim an estimated 19,700 acre-feet of return flows from the CUP, only about 77 percent of the supply would be derived from exchange of existing water rights in Utah Lake. The USGS assumed that planned importations of water from the Uinta Basin will be available and deliverable to fulfill the proposed exchanges. Water rights and demands are important for determining water availability. The USGS did not conduct an independent review of water rights and demands. The USSR and Utah Division of Water Rights use different methods in some areas for determining stress on the system based on past records. The USSR used "historical observed diversions" and the Utah Division of Water Rights use "diversion entitlements", which may not be equal to the historical diversions. The USGS based its review upon water demands used by the USSR. The Utah Division of Water Rights has responsibility for granting and enforcing water rights, and the final decisions on how the rights will be adjudicated lies with the Utah Division of Water Rights and with the courts. The USGS review did not consider the draft water distribution plan for the Utah Lake drainage basin proposed by the Utah State Engineer (written commun., October 15,1991). This plan, when finalized, may have an effect on water availability to the CUP.

Utah↗

USGS2023

Groundwater availability, geochemistry, and flow pathways to public-supply wells in the Atlantic Coastal Plain and bedrock aquifers, Aiken County and part of Lexington County, South Carolina, 2015–2019

Between 2015 and 2019, the U.S. Geological Survey (USGS) studied concerns related to projected increases in demand for groundwater, in collaboration with municipal water providers and county managers within the study area, Aiken County and part of Lexington County, South Carolina. A three-dimensional (3D), numerical groundwater-flow model of the Atlantic Coastal Plain (ACP) aquifers, confining units, and the underlying bedrock aquifer in the study area was constructed using the USGS software program MODFLOW–NWT in conjunction with a groundwater-recharge model using the Soil-Water-Balance (SWB) model. Water budgets for dry (2012) and wet (2015) year conditions, future (2017–2065) groundwater-demand scenarios based on general circulation models (GCMs) of future climates, and future agricultural irrigation demands were simulated. Overall, the GCMs projected increased recharge rates. Simulation of projected increased demand on groundwater by agriculture irrigation indicated little drawdown in the study area. Groundwater-quality samples were collected from representative public-supply wells (PSWs) and analyzed in the field and laboratory. In general, the groundwater in the ACP aquifers is acidic, dilute, and oxic. Conversely, groundwater in the bedrock aquifer was of neutral pH, mineralized, and anoxic. Total-radium concentrations across all PSWs ranged from 0.55 to 6.69 picocuries per liter (pCi/L). Groundwater from some PSWs contained detectable but low concentrations of commonly and historically used volatile organic compounds, such as chloroform, methyl tert -butyl ether (MTBE), cis -1,2-dichloroethylene ( cis -1,2-DCE), 1,1-dichloroethane (1,1-DCA), and 1,1-dichloroethylene (1,1-DCE). The stable isotopes of groundwater sampled from all wells indicate the possibility that groundwater from the bedrock aquifer may discharge into the ACP. Finally, groundwater age-dating results and MODPATH simulations indicate recharge between the 1950s and 1980s for PSWs in the ACP and recharge between the 1940s and 1950s for PSWs in bedrock. Maximum groundwater-flow pathways ranged from 270 to 7,470 feet, with the longest simulated-flow pathway for wells pumped at higher rates.

South Carolina↗

USGS2013

Benthic substrate classification map: Gulf Islands National Seashore

The 2005 hurricane season was devastating for the Mississippi Gulf Coast. Hurricane Katrina caused significant degradation of the barrier islands that compose the Gulf Islands National Seashore (GUIS). Because of the ability of coastal barrier islands to help mitigate hurricane damage to the mainland, restoring these habitats prior to the onset of future storms will help protect the islands themselves and the surrounding habitats. During Hurricane Katrina, coastal barrier islands reduced storm surge by approximately 10 percent and moderated wave heights (Wamsley and others, 2009). Islands protected the mainland by preventing ocean waves from maintaining their size as they approached the mainland. In addition to storm protection, it is advantageous to restore these islands to preserve the cultural heritage present there (for example, Fort Massachusetts) and because of the influence that these islands have on marine ecology. For example, these islands help maintain a salinity regime favorable to oysters in the Mississippi Sound and provide critical habitats for many migratory birds and endangered species such as sea turtles (Chelonia mydas, Caretta caretta, and Dermochelys coriacea), Gulf sturgeon (Acipenser oxyrinchus desotoi), and piping plovers (Charadrius melodus) (U.S. Army Corps of Engineers, 2009a). As land manager for the GUIS, the National Park Service (NPS) has been working with the State of Mississippi and the Mobile District of the U.S. Army Corps of Engineers to provide a set of recommendations to the Mississippi Coastal Improvements Program (MsCIP) that will guide restoration planning. The final set of recommendations includes directly renourishing both West Ship Island (to protect Fort Massachusetts) and East Ship Island (to restore the French Warehouse archaeological site); filling Camille Cut to recreate a continuous Ship Island; and restoring natural regional sediment transport processes by placing sand in the littoral zone just east of Petit Bois Island. Prevailing sediment transport processes will provide natural renourishment of the westward islands in the barrier system (U.S. Army Corps of Engineers, 2009b). One difficulty in developing the final recommendations is that few data are available to incorporate into restoration plans related to bathymetry, sediment type, and biota. For example, the most recent bathymetry available dates to when East and West Ship Islands were a single continuous island (1917). As a result, the MsCIP program has encouraged post-hurricane bathymetric data collection for future reference. Furthermore, managing a complex environment such as this barrier island system for habitat conservation and best resource usage requires significant knowledge about those habitats and resources. To effectively address these issues, a complete and comprehensive understanding of the type, geographic extent, and condition of marine resources included within the GUIS is required. However, the data related to the GUIS marine resources are limited either spatially or temporally. Specifically, there is limited knowledge and information about the distribution of benthic habitats and the characteristics of the offshore region of the GUIS, even though these are the habitats that will be most affected by habitat restoration. The goal of this project is to develop a comprehensive map of the benthic marine habitats within the GUIS to give park managers the ability to develop strategies for coastal and ocean-resource management and to aid decisionmakers in evaluating conservation priorities.

Mississippi↗

USGS2018

Inland waters

1. The total flux of carbon—which includes gaseous emissions, lateral flux, and burial—from inland waters across the conterminous United States (CONUS) and Alaska is 193 teragrams of carbon (Tg C) per year. The dominant pathway for carbon movement out of inland waters is the emission of carbon dioxide gas across water surfaces of streams, rivers, and lakes (110.1 Tg C per year), a flux not identified in the First State of the Carbon Cycle Report (SOCCR1; CCSP 2007). Second to gaseous emissions are the lateral fluxes of carbon through rivers to coastal environments (59.8 Tg C per year). Total carbon burial in lakes and reservoirs represents the smallest flux for CONUS and Alaska (22.5 Tg C per year) (medium confidence). 2. Based on estimates presented herein, the carbon flux from inland waters is now understood to be four times larger than estimates presented in SOCCR1. The total flux of carbon from inland waters across North America is estimated to be 507 Tg C per year based on a modeling approach that integrates high-resolution U.S. data and continental-scale estimates of water area, discharge, and carbon emissions. This estimate represents a weighted average of 24 grams of carbon per m2 per year of continental area exported and removed through inland waters in North America (low confidence). 3. Future research can address critical knowledge gaps and uncertainties related to inland water carbon fluxes. This chapter, for example, does not include methane emissions, which cannot be calculated as precisely as other carbon fluxes because of significant data gaps. Key to reducing uncertainties in estimated carbon fluxes is increased temporal resolution of carbon concentration and discharge sampling to provide better representations of storms and other extreme events for estimates of total inland water carbon fluxes. Improved spatial resolution of sampling also could potentially highlight anthropogenic influences on the quantity and quality of carbon fluxes in inland waters and provide information for land-use planning and management of water resources. Finally, uncertainties could likely be reduced if the community of scientists working in inland waters establishes and adopts standard measurement techniques and protocols similar to those maintained through collaborative efforts of the International Ocean Carbon Coordination Project and relevant governmental agencies from participating nations.

Book chapter↗

USGS2014

Disentangling the effects of climate and landscape change on bird population trends in the western U.S. and Canada

Changes in climate are often assumed result in changes to species’ ranges, with potential impacts on natural system functioning and ecosystem services. ‘Climate envelope models’, which rely on correlations between climate and species distributions, have been used to predict the future of biodiversity under these assumptions. However, other factors including land-cover, dispersal ability and interspecific competition and facilitation may play an important role in driving species distributions and population trends either alone or in combination with climate. In an ongoing project, we used long-term data on bird distributions and abundance to develop climate envelope and land-use models for 161 species in order to provide a multi-species test of the degree to which climate envelope versus land-use models are useful in predicting species distributions and population trends of birds in forest ecosystems of the western U.S. and Canada. Our results suggest that models describing associations between climatic variables and abundance patterns can be used for some species to predict changes through time, and that changes in climate have already driven shifts in the geographic patterns of abundance of bird populations in western North America. For other species, models using land-use variables including raw remote-sensing variables may provide the best predictions for abundance change. The results of this research showing the reliability of models across multiple species will aid managers in understanding which species are most vulnerable to changes from climate, land-use change and their interaction.

Final Report↗

USGS2019

A Methodology to Assess the National and Regional Impacts of U.S. Wind Energy Development on Birds and Bats

This scientific investigations report describes an effort by the U.S. Geological Survey (USGS) that used research, monitoring data, and modeling to develop a methodology to assess both the current and future population-level consequences of wind energy development on species of birds and bats that are present in the United States during any part of their life cycle. The methodology is currently applicable to birds and bats, focuses primarily on the effects of collisions with turbines, and can be applied to any species that breeds in, migrates through, or otherwise uses any part of the United States. The methodology assesses species at the national and regional scales and identifies those species potentially in need of more detailed study, as well as those species that are likely at low risk from wind energy development. This approach is fundamentally different from existing methods focusing on impacts at individual facilities. This report supersedes USGS Scientific Investigations Report 2015–5066 by the same authors, which described a preliminary version of the methodology. Following reviews of the preliminary methodology by a panel of external experts, public comments, and additional internal review, the methodology was revised and finalized. The three components of the refined methodology described in this new report rely on publicly available fatality information, population estimates, species range maps, turbine location data, biological characteristics of species, and population models. First, three metrics are combined to determine direct and indirect relative effects from wind energy facilities to generate a list of species scores. Second, a generic population model estimates the expected change in population trend caused by the additive mortality from collisions with wind turbines. Third, the methodology combines an estimate of observed fatalities and an estimate of potential biological removal to assess the possibility of a decrease in population size. The latter two components are quantitative. In a test case, the methodology was used to analyze data for six bird species and three bat species. Components of the methodology are based on simplifying assumptions and require information that, for many species, may be sparse or unreliable or may require further study. These assumptions should be carefully considered when using outputs from the methodology. Increases in the quality of data for fatalities from collisions with wind turbines, species distributions, abundance, and demography will likely improve results for uses of the methodology. The methodology’s design identifies and prioritizes a subset of the bird and bat species that may experience population-level impacts from collisions with wind turbines, both currently and from future wind energy development in the United States. Results of an assessment using this methodology could focus future research to improve our understanding of those impacts and to guide avoidance and minimization strategies. In addition, this methodology can be used to identify species for more intensive demographic modeling or to highlight those species that may not require any additional research because effects of wind energy development on their populations are projected to be small. The effects of wind energy facilities on nine unidentified species used in the test case described in this report have not been assessed. Their data were simply used to show the application of the methodology to real-world data and the types of outputs it would produce.

Scientific Investigations Report↗

USGS2025

The 3D National Topography Model Call for Action—Part 2: The Next Generation 3D Elevation Program

The three-dimensional (3D) National Topography Model initiative to integrate elevation and hydrography data includes the next generation of hydrography data from the 3D Hydrography Program and the next generation of elevation data from the 3D Elevation Program (3DEP). The first-ever collection of light detection and ranging (lidar) data for the nation (IfSAR for Alaska) provides a critical baseline reference, and the addition of multiple repeat elevation mapping projects as part of the next generation of 3DEP would substantially expand analysis capabilities. As the U.S. Geological Survey (USGS) is closing in on our goal of complete coverage with 3DEP data available or in progress for 98.3 percent of the Nation at the end of fiscal year 2024, the USGS is already transitioning to the next generation of 3DEP. Based on the 3D Nation Study results and input from a broad range of stakeholders, the USGS National Geospatial Program has finalized a new design for 3DEP that provides increased lidar quality levels and refresh rates. The new program is designed with more flexibility to meet changing user needs and take advantage of improvements in mapping technologies. The program will aim to expand the level of interagency coordination for topobathymetric lidar acquisition for inland rivers. The next generation of 3DEP will also aim to emphasize research, including advancing program design, products, and services and engaging and leveraging the evolving 3D industry. Research goals also include becoming more flexible in meeting user needs and taking advantage of evolving remote-sensing technologies. The program also plans to move from focusing on producing standard products to producing a concept of a 3D Nation Ecosystem with a variety of inputs, products, and services.

Circular↗

USGS2000

Hydrogeology and simulation of ground-water flow at the Gettysburg Elevator Plant Superfund Site, Adams County, Pennsylvania

Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other synthetic organic compounds. As part of the U.S. Environmental Protection Agency?s Comprehensive Environmental Response, Compensation, and Liability Act, 1980 process, a Remedial Investigation was completed in July 1991, a method of site remediation was issued in the Record of Decision dated June 1992, and a Final Design Report was completed in May 1997. In cooperation with the U.S. Environmental Protection Agency in the hydrogeologic assessment of the site remediation, the U.S. Geological Survey began a study in 1997 to determine the effects of the onsite and offsite extraction wells on ground-water flow and contaminant migration from the Gettysburg Elevator Plant. This determination is based on hydrologic and geophysical data collected from 1991 to 1998 and on results of numerical model simulations of the local ground-water flow-system. The Gettysburg Elevator Site is underlain by red, green, gray, and black shales of the Heidlersburg Member of the Gettysburg Formation. Correlation of natural-gamma logs indicates the sedimentary rock strike about N. 23 degrees E. and dip about 23 degrees NW. Depth to bedrock onsite commonly is about 6 feet but offsite may be as deep as 40 feet. The ground-water system consists of two zones?a thin, shallow zone composed of soil, clay, and highly weathered bedrock and a thicker, nonweathered or fractured bedrock zone. The shallow zone overlies the bedrock zone and truncates the dipping beds parallel to land surface. Diabase dikes are barriers to ground-water flow in the bedrock zone. The ground-water system is generally confined or semi-confined, even at shallow depths. Depth to water can range from flowing at land surface to more than 71 feet below land surface. Potentiometric maps based on measured water levels at the Gettysburg Elevator Plant indicate ground water flows from west to east, towards Rock Creek. Multiple-well aquifer tests indicate the system is heterogeneous and flow is primarily in dipping beds that contain discrete secondary openings separated by less permeable beds. Water levels in wells open to the pumped bed, as projected along the dipping stratigraphy, are drawn down more than water levels in wells not open to the pumped bed. Ground-water flow was simulated for steady-state conditions prior to pumping and long-term average pumping conditions. The three-dimensional numerical flow model (MODFLOW) was calibrated by use of a parameter estimation program (MODFLOWP). Steady-state conditions were assumed for the calibration period of 1996. An effective areal recharge rate of 7 inches was used in model calibration. The calibrated flow model was used to evaluate the effectiveness of the current onsite and offsite extraction well system. The simulation results generally indicate that the extraction system effectively captures much of the ground-water recharge at the Gettysburg Elevator Plant and, hence, contaminated ground-water migrating from the site. Some of the extraction wells pump at low rates and have very small contributing areas. Results indicate some areal recharge onsite will move to offsite extraction wells.

Pennsylvania↗

USGS2007

Great Basin Paleontological Bibliography

Introduction This work was conceived as a derivative product for 'The Metallogeny of the Great Basin' project of the Mineral Resources Program of the U.S. Geological Survey. In the course of preparing a fossil database for the Great Basin that could be accessed from the Internet, it was determined that a comprehensive paleontological bibliography must first be compiled, something that had not previously been done. This bibliography includes published papers and abstracts as well as unpublished theses and dissertations on fossils and stratigraphy in Nevada and adjoining portions of California and Utah. This bibliography is broken into first-order headings by geologic age, secondary headings by taxonomic group, followed by ancillary topics of interest to both paleontologists and stratigraphers; paleoecology, stratigraphy, sedimentary petrology, paleogeography, tectonics, and petroleum potential. References were derived from usage of Georef, consultation with numerous paleontologists and geologists working in the Great Basin, and literature currently on hand with the authors. As this is a Web-accessible bibliography, we hope to periodically update it with new citations or older references that we have missed during this compilation. Hence, the authors would be grateful to receive notice of any new or old papers that the readers think should be added. As a final note, we gratefully acknowledge the helpful reviews provided by A. Elizabeth J. Crafford (Anchorage, Alaska) and William R. Page (USGS, Denver, Colorado).

Open-File Report↗

USGS1977

Geographic information system development in the CARETS project

Experience in the development of a geographic information system to support the CARETS project has confirmed the considerable advantages that may accrue by paralleling the system development with a rational and balanced system production effort which permits the integration of the education and training of users with interim deliverable products to them. Those advantages include support for a long-term staff plan that recognizes substantial staff changes through system development and implementation, a fiscal plan that provides continuity in resources necessary for total system development, and a feedback system which allows the user to communicate his experiences in using the system. Thus far balance between system development and system production has not been achieved because of continuing large-scale spatial data processing requirements coupled with strong and insistent demands from users for immediately deliverable products from the system. That imbalance has refocussed staffing and fiscal plans from long-term system development to short- and near-term production requirements, continuously extends total system development time, and increases the possibility that later system development may reduce the usefulness of current interim products.

Final Report↗

USGS2022

The impact of future climate on wetland habitat in a critical migratory waterfowl corridor of the Prairie Pothole Region

Depressional wetlands are extremely sensitive to changes in temperature and precipitation, so understanding how wetland inundation dynamics respond to changes in climate is essential for describing potential effects on wildlife breeding habitat. Millions of depressional basins make up the largest wetland complex in North America known as the Prairie Pothole Region (PPR). The wetland ecosystems that have formed in these basins provide important migratory-bird breeding habitat. The southeast portion of the U.S. PPR in Minnesota and Iowa has faced some of the greatest challenges in wetland conservation. Many existing prairie-pothole wetlands are small (<1 ha) and shallow (<2 m) and are typically not inundated with surface water year-round. Our goal with this project is to increase the efficacy of mapping tools used by management agencies to predict future changes in water levels in the PPR. We accomplish this goal by improving the link between existing data (about wetland water characteristics) and existing tools (mapping products). Our results successfully validated (2009-2021) the current mapping tool (a wetland hydrology model) used by the U.S. Fish and Wildlife Service (USFWS) to manage 22 wetlands in Minnesota. We were able to hindcast wetland water levels to 1984 and assess the accuracy of a satellite-derived surface water product and forecast water levels through 2099 using a suite of modeled climate data. This newly refined link between monitoring data and remote sensing tools will increase understanding and prediction for other wetlands beyond our study sites and through the Minnesota and Iowa portions of the PPR. Through conference presentations, publications, and development of an interactive climate change dashboard we are now working with managers to determine how we can help incorporate these predicted changes to waterfowl breeding habitat into their future management, acquisition, and restoration strategy.

Alberta, Iowa, Manitoba, Minnesota, Montana, Nebra↗

USGS2024

Induced seismicity strategic vision

Executive Summary The U.S. Geological Survey has a long history of contributions to the understanding and resolution of various scientific questions related to earthquakes associated with human activities, referred to as induced seismicity. Work started with the Rocky Mountain Arsenal studies in the 1960’s (Healy and others, 1968) when it was first discovered that fluid waste-disposal operations can cause earthquakes. U.S. Geological Survey work on induced seismicity continued in the intervening years but expanded dramatically in the early 2010s. Disposal of large volumes of wastewater, a byproduct of oil and gas production, into the subsurface caused an exponential increase in earthquakes in the central United States, including earthquakes that caused damage to buildings and infrastructure in nearby communities. Established in 2012 within the Earthquake Hazards Program (EHP), the Induced Seismicity Project (ISP) examines earthquakes that are induced by human activities to assess and mitigate the hazards associated with induced earthquakes as well as understand the conditions and processes controlling induced and natural earthquake generation and recurrence. The ISP examines instances of suspected induced earthquakes, in real-time and retrospectively, to assess the probabilistic hazard and investigate possibilities for reducing that hazard, something currently not possible with natural earthquake activity. The ISP has many synergies with work across multiple areas of EHP, including earthquake monitoring, hazard mitigation, and fundamental research into earthquake processes. The overarching questions that guided the development of our research strategies and approaches are as follows: How can seismicity that is induced by industrial activities be better distinguished from natural processes, particularly in regions with higher rates of natural seismicity? Can faults that may be at increased hazard for induced seismicity be identified based on existing fault structures, past earthquake activity, local stress conditions, or other information? What geologic and operational conditions control the occurrence, spatial and temporal evolution, maximum magnitude, ground shaking, and other characteristics of induced seismic sequences? What roles do surface and subsurface deformation, aseismic slip, and other processes play in the occurrence of injection-induced earthquakes? How can induced seismicity be better forecasted to support the Nation’s energy production and climate mitigation goals while limiting related earthquake hazards? In this report, background on induced seismicity and an overview of the state of knowledge is provided in three topical task areas: (1) oil and gas, (2) geothermal, and (3) geologic CO2 sequestration. This report then presents the EHP’s goals, strategies, and approaches—primarily focused on work in the ISP—for understanding the conditions that lead to induced seismicity, mitigating the associated hazards, and assisting the Nation in meeting its future needs in energy production and mitigation of climate change. Finally, the key limitations and opportunities for innovation are outlined at the end of the report.

Circular↗

USGS2021

Fire refugia in old-growth forests: Predicting habitat persistence to support land management in an era of rapid global change

Recent stand-replacing wildfires in late-successional and old-growth (LSOG) forests have increased land manager interest in fire refugia, which could provide vital habitat for threatened and endangered species during a time of rapid change. The overall goal of this project was to model, map, and share information essential for the conservation of LSOG forest ecosystems in the U.S. Pacific Northwest, within a diverse co-production team of state and federal land managers. We developed statistical models of contemporary (2002-2017) fire refugia, non-stand-replacing fire (NSR), and high-severity fire based on topography, fuels, fire weather, fire behavior and climate. Independent models were built for two ecoregions (Figure 1), one encompassing the Douglas-fir/western hemlock forests of the northwestern portion of our study area and the other encompassing dry-mixed conifer forests of the eastern Cascades and Klamath-Siskiyou region. We used these models to produce probability surface maps for fire refugia, NSR, and high-severity fire under low, moderate, and extreme fire weather and fire growth scenarios. These maps and associated products provide timely information about the likely persistence, change, and loss of LSOG forests under current and future climate conditions.

California, Oregon, Washington↗