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At least 919 records · Page 51Linked to original sources
USGS2018

Nearshore single-beam bathymetry data collected in 2015, Dauphin Island, Alabama

Dauphin Island, Alabama, is a barrier island located in the northern Gulf of Mexico that supports local residences, tourism, commercial infrastructure, and historic Fort Gaines. During the past decade, Dauphin Island was affected by several major hurricanes—Hurricanes Ivan (2004), Katrina (2005), and Isaac (2012)—and storms, along with sea-level rise, continue to present a threat to island stability. State and Federal managers are using a scientific approach to identify, formulate, and implement a long-term plan to provide restoration options for Dauphin Island, thereby helping increase its resilience against future storms and sea-level rise. Island morphology, including current bathymetry and shoreline data, is one scientific domain being investigated in an effort to produce a comprehensive restoration plan funded by an interagency grant from the National Fish and Wildlife Foundation Gulf Environmental Benefit Fund . In August 2015, the U.S. Geological Survey ( USGS ) St. Petersburg Coastal and Marine Science Center ( SPCMSC ), in cooperation with the U.S. Army Corps of Engineers at the U.S. Army Engineer Research and Development Center, Mobile District, and the State of Alabama, conducted bathymetric surveys of the nearshore waters surrounding Dauphin Island. This report provides a detailed methodology for the data acquisition and post-processing of 1,165-line kilometers (km) of single-beam bathymetry data collected under the USGS–SPCMSC Alabama Barrier Island Restoration Study . These data were acquired and processed under USGS field activity number 2015–326–FA . Data are provided in three datums: (1) the International Terrestrial Reference Frame of 2000, ellipsoid height (from –47.04 meters (m) to –29.36 m); (2) the North American Datum of 1983, CORS96 realization (NAD83 (CORS96)) horizontal, and the North American Vertical Datum 1988 GEOID12A vertical (from –0.24 m to –17.33 m); and (3) NAD83 (CORS96) horizontal, and mean lower low water vertical (from –0.12 m to –17.93 m). The x,y,z point datasets, trackline shapefiles, digital and handwritten Field Activity Collection Systems logs, one 50-m digital elevation model, and formal Federal Geographic Data Committee metadata are obtainable from the Data Downloads page or the associated USGS data release .

Alabama↗
USGS2006

Geologic map of the west half of the Blythe 30' by 60' quadrangle, Riverside County, California and La Paz County, Arizona

The Blythe 30' by 60' quadrangle is located along the Colorado River between southeastern California and western Arizona. This map depicts the geology of the west half of the Blythe quadrangle, which is mostly in California. The map area is a desert terrain consisting of mountain ranges surrounded by extensive alluvial fans and plains, including the flood plain of the Colorado River which covers the easternmost part of the area. Mountainous parts of the area, including the Big Maria, Little Maria, Riverside, McCoy, and Mule Mountains, consist of structurally complex rocks that range in age from Proterozoic to Miocene. Proterozoic gneiss and granite are overlain by Paleozoic to Early Jurassic metasedimentary rocks (mostly marble, quartzite, and schist) that are lithostratigraphically similar to coeval formations of the Colorado Plateau region to the east. The Paleozoic to Jurassic strata were deposited on the tectonically stable North American craton. These rocks are overlain by metamorphosed Jurassic volcanic rocks and are intruded by Jurassic plutonic rocks that represent part of a regionally extensive, northwest-trending magmatic arc. The overlying McCoy Mountains Formation, a very thick sequence of weakly metamorphosed sandstone and conglomerate of Jurassic(?) and Cretaceous age, accumulated in a rapidly subsiding depositional basin south of an east-trending belt of deformation and east of the north-trending Cretaceous Cordilleran magmatic arc. The McCoy Mountains Formation and older rocks were deformed, metamorphosed, and locally intruded by plutonic rocks in the Late Cretaceous. In Oligocene(?) to Miocene time, sedimentary and minor volcanic deposits accumulated locally, and the area was deformed by faulting. Tertiary rocks and their Proterozoic basement in the Riverside and northeastern Big Maria Mountains are in the upper plate of a low-angle normal (detachment) fault that lies within a region of major Early to Middle Miocene crustal extension. Surficial deposits of the flanking alluvial fans and plains range in age from late Miocene to Holocene. Among the oldest of these deposits are limestone and fine-grained clastic sediments of the late Miocene and (or) Pliocene Bouse Formation, which is commonly interpreted to represent an estuary or marine embayment connected to the proto-Gulf of California. Most of the surficial deposits younger than the Bouse Formation are composed of alluvium either derived from local mountain ranges or transported into the area by the Colorado River. Large parts of the area, particularly near the northern margin, are covered by eolian sand, and small parts are covered by playa sediments.

Scientific Investigations Map↗
USGS2014

A method for determining transmissibility‐ and storage‐coefficients by tests of multiple well‐systems

Ground‐water has long been recognized as one of our important natural resources, but only in about the last 20 years has concentrated effort been made to place ground‐water hydrology on a quantitative basis. The quantitative approach to ground‐water work has been brought about largely through the leadership of O. E. MEINZER, Chief of the Ground‐Water Division of the Geological Survey, United States Department of the Interior, who has originated and applied many quantitative methods himself, and who has consistently fostered and encouraged this method of attack by his coworkers. That this effort has been ably directed and especially fruitful Is shown by the vast number of important ground‐water problems relating to the water‐supplies for war activities that have been worked out by means of quantitative methods in the last few years.

Eos, Transactions, American Geophysical Union↗
USGS2007

Geologic Map of the Big Delta B-1 Quadrangle, East-Central Alaska

Geologic mapping and U-Pb age dating of rocks from the Big Delta B-1 quadrangle, east-central Alaska, have yielded new insights into the geology and gold mineral resource for the headwater region of the Goodpaster River, northeast of Delta, Alaska. The area lies within the Yukon-Tanana Upland and is underlain by Paleozoic and Cretaceous crystalline bedrock and contains several gold mines and prospects. The Paleozoic units include biotite gneiss, quartzite interlayered with metapelite, and amphibolite gneiss. The Paleozoic units were intruded during the Devonian by tonalitic to granitic plutons, which, as a result of regional Mesozoic metamorphism and tectonism, are now augen gneiss and biotite orthogneiss. The Mesozoic regional metamorphism and ductile deformation of the entire Yukon-Tanana Upland culminated by the Late Cretaceous (about 116 Ma) as a result of northwest-directed regional transpression along the southern margin of the North American craton. This dynamothermal episode was followed by invasion of syn- to post-tectonic granodioritic to granitic batholiths during the Late Cretaceous (about 113-107 Ma), followed by a pulse of 100-95 Ma quartz feldspar porphyry intrusions. Gold mineralization is spatially associated with various post-tectonic Late Cretaceous granitic dikes and batholiths throughout the quadrangle. A northeast-trending structural corridor, described herein as the Black Mountain tectonic zone, both controlled the emplacement of some of the Cretaceous intrusive rocks, gold deposits, and prospects, as well as formed a deep-seated crustal conduit along which a subsequent rhyolite flow-dome complex erupted during the Paleocene. Tertiary uplift and erosion resulted in the development of extensive erosional pediments. Quaternary alpine glaciation carved beautiful, broad valleys in the eastern part of the quadrangle, leaving behind terminal moraines in the headwater region of the Goodpaster river drainage. Continued Holocene to Recent deformation along the Black Mountain tectonic zone has offset Tertiary terraces, as well as Quaternary fluvial and alluvial deposits, indicating that the area has a long, complex, and ongoing tectonic history.

Scientific Investigations Map↗
USGS1992

Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

Two upper Cenozoic depositional sequences of principally marine strata about 4000m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, late Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. -from Author

California↗
USGS2018

Status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers, Houston-Galveston region, Texas, 2018

Since the early 1900s, most of the groundwater withdrawals in the Houston-Galveston region, Texas, have been from the three primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers. Withdrawals from these aquifers are used for municipal supply, industrial, and irrigation purposes. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District, is one in an annual series of reports depicting the status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers in the Houston-Galveston region. This report contains regional-scale maps depicting approximate 2018 groundwater-level altitudes (represented by measurements made during December 2017 through March 2018) and long-term groundwater-level changes for the Chicot, Evangeline, and Jasper aquifers. In 2018, groundwater-level-altitude contours for the Chicot aquifer ranged from 200 feet (ft) below the North American Vertical Datum of 1988 (hereinafter referred to as “datum”) to 200 ft above datum. The 1977–2018 groundwater-level-change contours for the Chicot aquifer depict a large area of decline in groundwater-level altitudes (120 ft) in northwestern Harris County. The largest rise in groundwater-level altitudes in the Chicot aquifer from 1977 to 2018 (180 ft) was in southeastern Harris County. Groundwater-level-altitude contours for the Evangeline aquifer ranged from 250 ft below datum to 200 ft above datum in 2018. The 1977–2018 groundwater-level-change contours for the Evangeline aquifer depict broad areas where groundwater-level altitudes either declined or rose. The largest decline in groundwater-level altitudes (320 ft) was in southern Montgomery County. The largest rise in groundwater-level altitudes in the Evangeline aquifer from 1977 to 2018 (240 ft) was in southeastern Harris County. In 2018, groundwater-level-altitude contours for the Jasper aquifer ranged from 200 ft below datum to 200 ft above datum. The 2000–18 groundwater-level-change contours for the Jasper aquifer depict groundwater-level declines throughout most of the study area where groundwater-level-altitude data from the Jasper aquifer were collected, with the largest decline (200 ft) in southern Montgomery County.

Texas↗
USGS2019

Status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers, Houston-Galveston region, Texas, 2019

Since the early 1900s, most of the groundwater withdrawals in the Houston-Galveston region, Texas, have been from the three primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers. Withdrawals from these aquifers are used for municipal supply, commercial and industrial use, and irrigation. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District, is one in an annual series of reports depicting the status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers in the Houston-Galveston region. This report contains regional-scale maps depicting approximate 2019 groundwater-level altitudes (represented by measurements made during December 2018 through March 2019) and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers. In 2019, groundwater-level-altitude contours for the Chicot aquifer ranged from 200 feet (ft) below the North American Vertical Datum of 1988 (hereinafter referred to as “datum”) to 200 ft above datum. The 1977–2019 groundwater-level-change contours for the Chicot aquifer depict a large area of decline in groundwater-level altitudes (100 ft) in northwestern Harris County. The largest rise in groundwater-level altitudes in the Chicot aquifer from 1977 to 2019 (200 ft) was in southeastern Harris County. In 2019, groundwater-level-altitude contours for the Evangeline aquifer ranged from 300 ft below datum to 200 ft above datum. The 1977–2019 groundwater-level-change contours for the Evangeline aquifer depict broad areas where groundwater-level altitudes either declined or rose. The largest decline in groundwater-level altitudes (280 ft) was in southern Montgomery and northern Harris Counties. The largest rise in groundwater-level altitudes in the Evangeline aquifer from 1977 to 2019 (240 ft) was in southeastern Harris County. In 2019, groundwater-level-altitude contours for the Jasper aquifer ranged from 200 ft below datum to 250 ft above datum. The 2000–19 groundwater-level-change contours for the Jasper aquifer depict groundwater-level declines throughout most of the study area where groundwater-level-altitude data from the Jasper aquifer were collected, with the largest decline (200 ft) in southern Montgomery County.

Texas↗
USGS2020

Status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers, Houston-Galveston region, Texas, 2020

Since the early 1900s, most of the groundwater withdrawals in the Houston-Galveston region, Texas, have been from the three primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers. Withdrawals from these aquifers are used for municipal supply, commercial and industrial use, and irrigation. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District, is one in an annual series of reports depicting the status of groundwater-level altitudes and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers in the Houston-Galveston region. This report contains regional-scale maps depicting approximate 2020 groundwater-level altitudes (represented by measurements made during December 2019 through March 2020) and long-term groundwater-level changes in the Chicot, Evangeline, and Jasper aquifers. In 2020, groundwater-level-altitude contours for the Chicot aquifer ranged from 150 feet (ft) below the North American Vertical Datum of 1988 (hereinafter referred to as “datum”) to 200 ft above datum. The 1977–2020 groundwater-level-change contours for the Chicot aquifer depict a large area of decline in groundwater-level altitudes (120 ft) in northwestern Harris County. The largest rise in groundwater-level altitudes in the Chicot aquifer from 1977 to 2020 (200 ft) was in southeastern Harris County. In 2020, groundwater-level-altitude contours for the Evangeline aquifer ranged from 250 ft below datum to 200 ft above datum. The 1977–2020 groundwater-level-change contours for the Evangeline aquifer depict broad areas where groundwater-level altitudes either declined or rose. The largest decline in groundwater-level altitudes (280 ft) was in southern Montgomery and northern Harris Counties. The largest rise in groundwater-level altitudes in the Evangeline aquifer from 1977 to 2020 (240 ft) was in southeastern Harris County. In 2020, groundwater-level-altitude contours for the Jasper aquifer ranged from 200 ft below datum to 250 ft above datum. The 2000–20 groundwater-level-change contours for the Jasper aquifer depict groundwater-level declines throughout most of the study area where groundwater-level-altitude data from the Jasper aquifer were collected, with the largest decline (220 ft) in southern Montgomery County.

Texas↗
USGS2022

Status and understanding of groundwater quality in the Sacramento Metropolitan Domestic-Supply Aquifer study unit, 2017—California GAMA Priority Basin Project

Groundwater quality in the Sacramento Metropolitan Domestic-Supply Aquifer study unit (SacMetro-DSA) was studied from August to November 2017 as part of the second phase of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in parts of Amador, Placer, Sacramento, and Sutter Counties, and the extent of the study unit was defined by the location of three California Department of Water Resources groundwater subbasins: the North American, the South American, and the Cosumnes. The SacMetro-DSA focused on groundwater resources used for domestic drinking-water supply, which generally correspond to shallower parts of aquifer systems than those of groundwater resources used for public drinking water supply in the same area. The assessments characterized the quality of untreated groundwater, not the quality of drinking water. This study included two components: (1) a status assessment, which characterized the status of the quality of the groundwater resources used for domestic supply and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting water quality in those resources. The first component of this study—the status assessment—was based on water-quality data collected from 49 sites sampled by the U.S. Geological Survey for the GAMA Priority Basin Project in 2017. The samples were analyzed for volatile organic compounds, pesticides, and naturally present inorganic constituents, such as major ions and trace elements. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency and California State Water Resources Control Board Division of Drinking Water regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a grid-based method to estimate the proportion of the groundwater resources that had concentrations of water-quality constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale and permits comparisons to other GAMA Priority Basin Project study areas. The second component of this study—the understanding assessment—identified the natural and human factors that potentially affect groundwater quality by evaluating land-use characteristics, groundwater age, and geochemical and hydrologic conditions of the domestic-supply aquifer and related these data to constituents identified in the status assessment for further evaluation. In the SacMetro-DSA study unit, arsenic was the only inorganic constituent detected above health-based benchmarks and was detected in 10 percent of the domestic-supply aquifer system. Inorganic constituents were detected above the non-health-based California State Water Resources Control Board—Division of Drinking Water secondary maximum contaminant levels (SMCL-CA) in 16 percent of the system. The inorganic constituents detected above the SMCL-CA were chloride, iron, manganese, and total dissolved solids (TDS). Organic constituents (volatile organic compounds and pesticides) with health-based benchmarks were not detected above health-based benchmarks; however, chloroform was detected at concentrations higher than 10 percent of the health-based benchmark (80 micrograms per liter) in 2 percent of the domestic-supply aquifer system. Of the 310 organic constituents analyzed, 16 constituents were detected; however, only bentazon and chloroform had detection frequencies greater than 10 percent. Inorganic constituents with health-based benchmarks that were evaluated in the understanding assessment included arsenic and hexavalent chromium. Arsenic and hexavalent chromium are natural constituents of aquifer sediments in the study unit and did not appear to be influenced by anthropogenic processes; rather, the presence of arsenic and hexavalent chromium appeared to be related to geochemical conditions controlled by oxidation–reduction reactions in the aquifer system. Naturally occurring inorganic constituents with SMCL-CAs evaluated in the understanding assessment were the trace elements iron and manganese, the major ion chloride, and TDS. Like arsenic and hexavalent chromium, the presence of iron and manganese was most strongly related to geochemical conditions in the aquifer system, specifically reducing conditions, which were most common near the western edge of the study unit close to the Sacramento River. Concentrations of chloride and TDS are indicators of salinity and were correlated with variables related to well location and included redox, agricultural land use, and elevation. Chloride and TDS were positively correlated to reducing conditions, and agricultural land use was negatively correlated to elevation and well depth. Observed correlations among variables were likely driven by the characteristics of the western part of the study unit, such as its higher proportion of agricultural land use and its relatively low elevation. A large portion of the western edge of the study unit is located in the center of the Sacramento Valley, defined by the location of the Sacramento River. The special-interest constituent perchlorate, also included in the understanding assessment, has natural and anthropogenic sources. Perchlorate was detected frequently and at moderate relative concentrations. In some areas of the study unit, concentrations of perchlorate were higher than what might be expected in nature; therefore, anthropogenic introduction of perchlorate or anthropogenically induced migration of native perchlorate could be occurring.

California↗
USGS2007

The National Streamflow Statistics Program: A Computer Program for Estimating Streamflow Statistics for Ungaged Sites

The National Streamflow Statistics (NSS) Program is a computer program that should be useful to engineers, hydrologists, and others for planning, management, and design applications. NSS compiles all current U.S. Geological Survey (USGS) regional regression equations for estimating streamflow statistics at ungaged sites in an easy-to-use interface that operates on computers with Microsoft Windows operating systems. NSS expands on the functionality of the USGS National Flood Frequency Program, and replaces it. The regression equations included in NSS are used to transfer streamflow statistics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally, the equations were developed on a statewide or metropolitan-area basis as part of cooperative study programs. Equations are available for estimating rural and urban flood-frequency statistics, such as the 1 00-year flood, for every state, for Puerto Rico, and for the island of Tutuila, American Samoa. Equations are available for estimating other statistics, such as the mean annual flow, monthly mean flows, flow-duration percentiles, and low-flow frequencies (such as the 7-day, 0-year low flow) for less than half of the states. All equations available for estimating streamflow statistics other than flood-frequency statistics assume rural (non-regulated, non-urbanized) conditions. The NSS output provides indicators of the accuracy of the estimated streamflow statistics. The indicators may include any combination of the standard error of estimate, the standard error of prediction, the equivalent years of record, or 90 percent prediction intervals, depending on what was provided by the authors of the equations. The program includes several other features that can be used only for flood-frequency estimation. These include the ability to generate flood-frequency plots, and plots of typical flood hydrographs for selected recurrence intervals, estimates of the probable maximum flood, extrapolation of the 500-year flood when an equation for estimating it is not available, and weighting techniques to improve flood-frequency estimates for gaging stations and ungaged sites on gaged streams. This report describes the regionalization techniques used to develop the equations in NSS and provides guidance on the applicability and limitations of the techniques. The report also includes a users manual and a summary of equations available for estimating basin lagtime, which is needed by the program to generate flood hydrographs. The NSS software and accompanying database, and the documentation for the regression equations included in NSS, are available on the Web at http://water.usgs.gov/software/.

Techniques and Methods↗
USGS1987

Checklist of vertebrates of the United States, the U.S. territories, and Canada

On 30 January 1980 the Policy Group of the 1978 Interagency Agreement on Classifications and Inventory established a work group on fish and wildlife species names. The participating agencies were the Fish and Wildlife Service, Forest Service, Bureau of Land Management, Geological Survey, and Soil Conservation Service. The Fish and Wildlife Service was assigned the role of establishing and leading this work group in developing a national list of standard vertebrate species names that is up-to-date and accurate. The Association of Systematic Collections was contracted to develop the reference list. This publication is a revision of portions of the list (amphibians, reptiles, birds, and mammals), including updating to the end of 1985. The geographic areas encompassed by this list are: the United States, including Alaska and Hawaii; the Commonwealth of Puerto Rico, the U.S. Virgin Islands, and Navassa Island; the Trust Territory of the Pacific Islands (the Caroline Islands, Palau Islands, Marshall Islands, and northern Mariana Islands); and the U.S. Territories of American Samoa, Baker Island, Guam, Howland Island, Jarvis Island, the Johnston Islands, Kingman Reef, the Midway Islands, and Wake Islands. Canadian species that do not also occur in the United States have been included. This list includes the names of all Recent species known to occur, or to have occurred, in the geographic areas indicated above. No distinction is made between resident and migratory species or between those that occur regularly and those of casual or accidentally occurrence. The occurrence of all species listed is documented by specimen or photographic evidence. Zoo, aquarium, game park, and hunting preserve populations are not listed, nor are unestablished escapes from such populations. Species that are extinct are marked with a 1 . Species whose only occurrence in an area is the result of introduction by man are marked with a 2 . Species introduced into one area but native to another covered by this checklist do not have a superscript, nor do species for which the documentation of introduction is equivocal. Species listed as Endangered or Threatened (as of January 1987) throughout their ranges are marked with a 3 , whereas species with only selected subspecies or populations so listed are marked with a 4 . Refer to the Code of Federal Regulations (50 CFR) for further details on the Endangered Species Act of 1973 and its requirements. The list includes the scientific names and English names of taxa from order to species. At the level of genus and above, more than one English name may be given; this is to indicate content, not alternative names. English (common or vernacular) names for species vary from region to region and from author to author. The name "gopher", for example, has been applied to kinds of animals as diverse as pocket gophers, ground squirrels, and turtles. Most species have names in other languages as well as English names, and some species lack generally accepted English names. A single English name is given for each species in this list to promote uniformity and to permit more precise communication among users. Accurate communication about species can be assured only by using the scientific names, including their authors and date. We provide an "exploded" illustration (Fig. 1) of a typical portion of the list and identify the elements of each citation.

Resource Publication↗
USGS2011

I3N risk assessment and pathway analysis: Tools for the prevention of biological invasions

Information on invasive alien species from published and unpublished accounts and databases is usually scattered in locations and formats that are not easily accessible. Customized informatics tools for collecting and organizing invasive species information can help resource managers better control biological invasions. The Invasives Information Network (I3N) of the Inter-American Biodiversity Information Network has created a distributed network of databases of invasive species profiles, subject matter experts, projects, and datasets hosted and published online by natural resource institutions throughout the Americas. Invasive species information is documented and published online in a standard format that can be searched by the public. Profiles and occurrence information on invaders can be documented using the I3N Database on Invasive Alien Species, published online using an easy-to-use template, and exchanged in standard formats. The I3N Risk Assessment and Pathway Analysis tools are designed to be used in conjunction with I3N Databases to assist decision-makers in setting priorities for containment. All these tools are freely available online at http://i3n.iabin.net. Coordinated by the United States Geological Survey National Biological Information Infrastructure, this network serves as an example of successful capacity building and regional collaboration on an issue of global significance.

Conference Paper↗
USGS2014

Development of limestone reservoirs in Comal County, Texas

The Edwards limestone, and to a lesser extent the Comanche Peak limestone and the lower part of the Glen Rose limestone below, all of Lower Cretaceous age, form one of the most extensive ground‐water reservoirs in Texas. As a result of normal faulting, these formations are connected by underground channels to form a hydrologic unit which is partly artesian and partly unconfined. Observations in Comal County show that the development of the reservoir by solution is closely related to the geologic history, in which complex faulting and the disconformity between the Edwards and Georgetown limestones are important factors. Various phases of development are shown in different fault blocks, depending upon length of exposure at the surface. The Edwards limestone, which contains the main channels of underground drainage, is almost uniformly permeable from top to bottom, whereas the older, but more recently exposed lower part of the Glen Rose limestone is generally relatively impermeable except where exposed by mature streams.

Texas↗
USGS2008

Joint NOAA/NWS/USGS prototype debris flow warning system for recently burned areas in Southern California

Debris flows, also known as mudslides, are composed gravity-driven mixtures of sediment and water that travel through steep channels, over open hillslopes, and the like. Addressing this issue, US Geological Survey (USGS) and NOAA have established a debris-flow warning system that has the ability to monitor and forecast precipitation and issue timely weather hazard warning. In 2005, this joint NOAA-USGS prototype debris-flow warning system was issued in Southern California and as a result, it has provided valuable information to emergency managers in affected communities.

California↗
USGS2009

Advancing techniques to constrain the geometry of the seismic rupture plane on subduction interfaces a priori: Higher-order functional fits

Ongoing developments in earthquake source inversions incorporate nonplanar fault geometries as inputs to the inversion process, improving previous approaches that relied solely on planar fault surfaces. This evolution motivates advancing the existing framework for constraining fault geometry, particularly in subduction zones where plate boundary surfaces that host highly hazardous earthquakes are clearly nonplanar. Here, we improve upon the existing framework for the constraint of the seismic rupture plane of subduction interfaces by incorporating active seismic and seafloor sediment thickness data with existing independent data sets and inverting for the most probable nonplanar subduction geometry. Constraining the rupture interface a priori with independent geological and seismological information reduces the uncertainty in the derived earthquake source inversion parameters over models that rely on simpler assumptions, such as the moment tensor inferred fault plane. Examples are shown for a number of wellconstrained global locations. We expand the coverage of previous analyses to a more uniform global data set and show that even in areas of sparse data this approach is able to accurately constrain the approximate subduction geometry, particularly when aided with the addition of data from local active seismic surveys. In addition, we show an example of the integration of many two-dimensional profiles into a threedimensional surface for the Sunda subduction zone and introduce the development of a new global threedimensional subduction interface model: Slab1.0. ?? 2009 by the American Geophysical Union.

Geochemistry, Geophysics, Geosystems↗
USGS2014

Magnetic studies of the Florida peninsula

This investigation was undertaken primarily as a pilot‐experiment for gaining information concerning the field‐technique and accuracy which is needed for covering large areas in detail and at the same time economically. Owing to the complex nature of magnetic observations, such a pilot‐study serves, in addition, as a basis for determining the best methods of presenting the results of large areal studies in an easily comprehensible form. The State of Florida was chosen for such preliminary study for the following reasons: First, because it is geologically ideal for such an investigation since it comprises a series of unconsolidated, flat‐lying, Tertiary and Cretaceous sediments of low magnetic permeability covering a complex and much‐folded crystalline basement composed largely of rocks carrying strongly paramagnetic materials; secondly, because information concerning the structural trends of the crystalline basement would be of great interest and importance in the study of Appalachian orogeny and the relationship of the Florida Peninsula to both the Appalachian and Antillean tectonic systems.

Florida↗
USGS2016

Variability and trends in runoff efficiency in the conterminous United States

Variability and trends in water-year runoff efficiency (RE) — computed as the ratio of water-year runoff (streamflow per unit area) to water-year precipitation — in the conterminous United States (CONUS) are examined for the 1951 through 2012 period. Changes in RE are analyzed using runoff and precipitation data aggregated to United States Geological Survey 8-digit hydrologic cataloging units (HUs). Results indicate increases in RE for some regions in the north-central CONUS and large decreases in RE for the south-central CONUS. The increases in RE in the north-central CONUS are explained by trends in climate, whereas the large decreases in RE in the south-central CONUS likely are related to groundwater withdrawals from the Ogallala aquifer to support irrigated agriculture.

Journal of the American Water Resources Associatio↗
USGS2021

Nitrogen and phosphorus sources and delivery from the Mississippi/Atchafalaya River Basin: An update using 2012 SPARROW models

Nitrogen (N) and phosphorus (P) inputs throughout the Mississippi/Atchafalaya River Basin (MARB) have been linked to the Gulf of Mexico hypoxia and water‐quality problems throughout the MARB. To describe N and P loading throughout the MARB, SPAtially Referenced Regression On Watershed attributes (SPARROW) models were previously developed based on nutrient inputs and management similar to 1992 and 2002. In this study, refined SPARROW models were developed with higher resolution basin delineation, updated (2012) source inputs, improved calibration (load) targets, and additional statistical techniques than used in the previous SPARROW models. Based on the refined models, consistent with past models, N and P loads/yields were the highest from the central part of the MARB (Corn Belt) and along the Mississippi River. Agricultural activities remained the most important N and P source, but more so for N because its input, which could now be distinguished from atmospheric deposition, could be estimated. Natural loss of P from geologic material throughout the MARB was an important source, contributing about 23% of the total P from the MARB, and resulted in specific areas, such as Kentucky and Tennessee, being larger sources of P than previously estimated. This information can help managers decide where efforts will have the largest effects (highest ranked areas) on reducing nutrient loading to the Gulf hypoxia and what are the most important sources of N and P in these areas.

Mississippi/Atchafalaya River Basin↗