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At least 469 records · Page 26Linked to original sources
USGS1974

Environmental impact analysis; the example of the proposed Trans-Alaska Pipeline

The environmental impact analysis made as required by the National Environmental Policy Act of 1969 for the proposed trans-Alaska pipeline included consideration of the (1) technologically complex and geographically extensive proposed project, (2) extremely different physical environments across Alaska along the proposed route and elsewhere in Alaska and in Canada along alternative routes, (3) socioeconomic environment of the State of Alaska, and (4) a wide variety of alternatives. The analysis was designed specifically to fit the project and environment that would be affected. The environment was divided into two general parts--natural physical systems and superposed socioeconomic systems--and those parts were further divided into discipline-oriented systems or components that were studied and analyzed by scientists of the appropriate discipline. Particular attention was given to potential feedback loops in the impact network and to linkages between the project's impacting effects and the environment. The results of the analysis as reported in the final environmental impact statement were that both unavoidable and threatened environmental impacts would result from construction, operation, and maintenance of the proposed pipeline system and the developments related to it. The principal unavoidable effects would be (1) disturbances of terrain, fish and wildlife habitat, and human environs, (2) the results of the discharge of effluent from the tanker-ballast-treatment facility into Port Valdez and of some indeterminate amount of oil released into the ocean from tank-cleaning operations at sea, and (3) the results associated with increased human pressures of all kinds on the environment. Other unavoidable effects would be those related to increase of State and Native Corporation revenues, accelerated cultural change of the Native population, and extraction of the oil and gas resource. The main threatened environmental effects would all be related to unintentional oil loss from the pipeline, from tankers, or in the oil field. Oil losses from the pipeline could be caused by direct or indirect effects of earthquakes, destructive sea waves, slope failure caused by natural or artificial processes, thaw-plug instability (in permafrost), differential settlement of permafrost terrain, and bed scour and bank erosion at stream crossings. Oil loss from tankers could be caused by accidents during transfer operations at Valdez and at destination ports and by casualties involving tankers and other ships. Comparison of alternative routes and transportation systems and of their environmental impacts provided information which indicates to the author that one corridor containing both oil and gas pipelines would have less environmental impact than would separate corridors. Considering also the threat to the marine environment that any tanker system would impose and the threat that zones of high earthquake frequency and magnitude would impose on pipelines, it is apparent to the author that environmental impact and cost would be least for a single-corridor on-land route that avoided earthquake zones. The alternative trans-Alaska-Canada routes would meet these criteria. The decisions of the U.S. Department of the Interior, the U.S. Congress, and the President of the United States in favor of the proposed trans-Alaska pipeline system indicate the relative weight given by the decision makers in balancing the importance of potential environmental consequences against the advantages to be derived from rapid resource development.

Circular↗
USGS2001

Geologic map of the Tucson and Nogales quadrangles (Arizona, scale 1:250,000): A digital database

The geologic map of the Tucson-Nogales 1:250,000 scale quadrangle (Peterson and others, 1990) was digitized by U.S. Geological Survey staff and University of Arizona contractors at the Southwest Field Office, Tucson, Arizona, in 2000 for input into a geographic information system (GIS). The database was created for use as a basemap in a decision support system designed by the National Industrial Minerals and Surface Processes project. The resulting digital geologic map database can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included; they may be obtained from a variety of commercial and government sources. Additionally, point features, such as strike and dip, were not captured from the original paper map and are not included in the database. This database is not meant to be used or displayed at any scale larger than 1:250,000 (for example, 1:100,000 or 1:24,000). The digital geologic map graphics and plot files that are provided in the digital package are representations of the digital database. They are not designed to be cartographic products.

Arizona↗
USGS2014

Ecoregions of Arizona (poster)

Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The Arizona ecoregion map was compiled at a scale of 1:250,000. It revises and subdivides an earlier national ecoregion map that was originally compiled at a smaller scale. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions. At level III, the continental United States contains 105 ecoregions and the conterminous United States has 85 ecoregions. Level IV is a further subdivision of level III ecoregions. Arizona contains arid deserts and canyonlands, semiarid shrub- and grass-covered plains, woodland- and shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated peaks, and river alluvial floodplains. Ecological diversity is remarkably high. There are 7 level III ecoregions and 52 level IV ecoregions in Arizona and many continue into ecologically similar parts of adjacent states. This poster is part of a collaborative project primarily between the U.S. Geological Survey (USGS), USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), USEPA Region IX, U.S. Department of Agriculture (USDA)–Natural Resources Conservation Service (NRCS), The Nature Conservancy, and several Arizona state agencies. The project is associated with an interagency effort to develop a common national framework of ecological regions. Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies applied to develop the most common ecoregion-type frameworks, including those developed by the USDA–Forest Service, the USEPA, and the NRCS. As each of these frameworks is further refined, their differences are becoming less discernible. Collaborative ecoregion projects, such as this one in Arizona, are a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation.

Arizona↗
USGS2019

Offshore shallow structure and sediment distribution, Punta Gorda to Point Arena, Northern California

This publication consists of two map sheets that display shallow geologic structure, along with sediment distribution and thickness, for an approximately 150-km-long offshore section of the northern California coast between Punta Gorda and Point Arena. Each map sheet includes three maps at scales of either 1:100,000 or 1:200,000, and together the sheets include 30 figures that contain representative high-resolution seismic-reflection profiles. The maps and seismic-reflection surveys cover most of the continental shelf in this region. In addition, the maps show the locations of the shelf break and the 3-nautical-mile limit of California’s State Waters. The seismic-reflection data, which are the primary dataset used to develop the maps, were collected to support the California Seafloor Mapping Program, U.S. Geological Survey Offshore Geologic Hazards projects, and National Oceanic and Atmospheric Administration’s (NOAA’s) Ocean Explorer program. In addition to the two map sheets, this publication includes geographic information system data files of faults, sediment thicknesses, and depths-to-base of sediment The map area includes the northernmost section of the right-lateral San Andreas Fault, which extends offshore from Point Arena in the south to Point Delgada in the north. The San Andreas Fault is the primary structure in the widely distributed plate boundary between the Pacific Plate and the Sierra Nevada–Great Valley Microplate, with estimates of cumulative right slip of as much as up to 450 km. South of Point Delgada, fault-related transtension has resulted in development of the Noyo Basin. North of Point Delgada, the San Andreas Fault transitions into a complex contractional zone in and (or) south of the King Range, including a possible nearshore fault that may connect with the Mattole Canyon Fault. Quaternary sediments and bedrock underlie the shelf. On the seismic-reflection profiles, we digitally traced the thickness and depth of the uppermost seismic-stratigraphic unit, which is a focus of this publication. The upper contact of this unit is the seafloor; the lower contact is a transgressive surface of erosion, a commonly angular, wave-cut unconformity characterized by an upward change to lower amplitude, more diffuse reflections. On the basis of this lower contact, this stratigraphic unit is inferred to have been deposited on the shelf in the last about 21,000 years during the sea-level rise that followed the last major lowstand and the Last Glacial Maximum (LGM). Maps in this publication show both the thickness of this upper sediment unit and the depth to the base of the sediment unit. Within the map region, five different “domains” of post-LGM shelf sediment are delineated on the basis of sediment thickness and coastal geomorphology. Maximum sediment thickness (as much as 67 m) is found in the northern part of the region, along the steep south flank of the King Range. Minimum sediment thickness (areas of exposed bedrock) is found on fault-bounded uplifts, which include Tolo bank and Punta Gorda bank. Mean sediment thickness for the entire shelf in the map area between Punta Gorda and Point Arena is 8.9 m, and total sediment volume is 12,824×10 6 m 3 .

California↗
USGS2006

Sources and occurrence of chloroform and other trihalomethanes in drinking-water supply wells in the United States, 1986-2001

Chloroform and three other trihalomethanes (THMs)--bromodichloromethane, dibromochloromethane, and bromoform--are disinfection by-products commonly produced during the chlorination of water and wastewater. Samples of untreated ground water from drinking-water supply wells (1,096 public and 2,400 domestic wells) were analyzed for THMs and other volatile organic compounds (VOCs) during 1986-2001, or compiled, as part of the U.S. Geological Survey's National Water-Quality Assessment Program. This report provides a summary of potential sources of THMs and of the occurrence and geographical distribution of THMs in samples from public and domestic wells. Evidence for an anthropogenic source of THMs and implications for future research also are presented. Potential sources of THMs to both public and domestic wells include the discharge of chlorinated drinking water and wastewater that may be intentional or inadvertent. Intentional discharge includes the use of municipally supplied chlorinated water to irrigate lawns, golf courses, parks, gardens, and other areas; the use of septic systems; or the regulated discharge of chlorinated wastewater to surface waters or ground-water recharge facilities. Inadvertent discharge includes leakage of chlorinated water from swimming pools, spas, or distribution systems for drinking water or wastewater sewers. Statistical analyses indicate that population density, the percentage of urban land, and the number of Resource Conservation and Recovery Act hazardous-waste facilities near sampled wells are significantly associated with the probability of detection of chloroform, especially for public wells. Domestic wells may have several other sources of THMs, including the practice of well disinfection through shock chlorination, laundry wastewater containing bleach, and septic system effluent. Chloroform was the most frequently detected VOC in samples from drinking-water supply wells (public and domestic wells) in the United States. Although chloroform was detected frequently in samples from public and domestic wells and the other THMs were detected in some samples, no concentrations in samples from either well type exceeded the U.S. Environmental Protection Agency's Maximum Contaminant Level of 80 micrograms per liter for total THMs. Chloroform was detected in public well samples almost twice as frequently (11 percent) as in domestic well samples (5 percent). The other three THMs also were detected more frequently in public well samples than in domestic well samples. This detection pattern may be attributed to public wells having a higher pumping capacity than domestic wells. The higher capacity wells create a larger capture zone that potentially intercepts more urban and other land uses and associated point and nonpoint sources of contamination than the smaller capacity domestic wells. THM detection frequencies in domestic well samples show a pattern of decreasing frequency with increasing bromide content, that is in the order: chloroform > bromodichloromethane >= dibromochloromethane >= bromoform. This same pattern has been documented in studies of water chlorination, indicating that an important source of chloroform and other THMs in drinking-water supply wells may be the recycling of chlorinated water and wastewater. Mixtures of THMs commonly occur in public well samples, and the most frequently occurring are combinations of the brominated THMs. These THMs have limited industrial production, few natural sources, and small or no reported direct releases to the environment. Therefore, industrial, commercial, or natural sources are not likely sources of the brominated THMs in public and domestic well samples. The THM detection frequency pattern, the co-occurrence of brominated THMs, and other lines of evidence indicate that the recycling of water with a history of chlorination is an important source of these compounds in samples from drinking-water supply wells.

Scientific Investigations Report↗
USGS2019

Flood-inundation maps for a 23-mile reach of the Medina River at Bandera, Texas, 2018

In 2018, the U.S. Geological Survey (USGS), in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, studied floods through the period of record to create a library of flood-inundation maps for the Medina River at Bandera, Texas. Digital flood-inundation maps for a 23-mile reach of the Medina River at and near Bandera, from the confluence with Winans Creek to English Crossing Road, were developed. The flood-inundation maps depict estimates of the areal extent and depth of flooding corresponding to a range of different gage heights (gage height is commonly referred to as “stage,” or the water-surface elevation at a streamflow-gaging station) at USGS streamflow-gaging station 08178880 Medina River at Bandera, Tex. (hereinafter referred to as the “Bandera station”). Water-surface profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The stage-discharge (streamflow) relation effective in 2018 was used to calibrate the model, and stages from four recent flood events were used to independently validate the model. The calibrated hydraulic model was then used to compute 29 water-surface profiles for stages at 1-foot (ft) increments referenced to the station datum and ranging from 10 ft (near bankfull) to 38 ft, which exceeds the major flood stage of the National Weather Service Advanced Hydrologic Prediction Service of 24 ft. The simulated water-surface profiles were then combined with a geographic information system digital elevation model (derived from light detection and ranging data having a 0.4-ft vertical accuracy and 1.6-ft horizontal resolution) to delineate the area flooded for stages ranging from 10 to 38 ft. The digital flood-inundation maps are delivered through the USGS Flood Inundation Mapper application that presents map libraries and provides detailed information on flood-inundation extents and stages for modeled sites. The flood-inundation maps developed in this study, in conjunction with the real-time stage data from the Bandera station, are intended to help guide the public in taking individual safety precautions and provide emergency management personnel with a tool to efficiently manage emergency flood operations and post-flood recovery efforts.

Scientific Investigations Report↗
USGS2000

Mapping and converting essential Federal Geographic Data Committee (FGDC) metadata into MARC21 and Dublin Core: towards an alternative to the FGDC Clearinghouse

The purpose of this article is to raise and address a number of issues related to the conversion of Federal Geographic Data Committee metadata into MARC21 and Dublin Core. We present an analysis of 466 FGDC metadata records housed in the National Biological Information Infrastructure (NBII) node of the FGDC Clearinghouse, with special emphasis on the length of fields and the total length of records in this set. One of our contributions is a 34 element crosswalk, a proposal that takes into consideration the constraints of the MARC21 standard as implemented in OCLC's World Cat and the realities of user behavior.

D-Lib↗
USGS2000

Monitoring survival rates of landbirds at varying spatial scales: An application of the MAPS Program

Survivorship is a primary demographic parameter affecting population dynamics, and thus trends in species abundance. The Monitoring Avian Productivity and Survivorship (MAPS) program is a cooperative effort designed to monitor landbird demographic parameters. A principle goal of MAPS is to estimate annual survivorship and identify spatial patterns and temporal trends in these rates. We evaluated hypotheses of spatial patterns in survival rates among a collection of neighboring sampling sites, such as within national forests, among biogeographic provinces, and between breeding populations that winter in either Central or South America, and compared these geographic-specific models to a model of a common survival rate among all sampling sites. We used data collected during 1992-1995 from Swainson's Thrush (Cathorus ustulatus) populations in the western region of the United States. We evaluated the ability to detect spatial and temporal patterns of survivorship with simulated data. We found weak evidence of spatial differences in survival rates at the local scale of 'location,' which typically contained 3 mist-netting stations. There was little evidence of differences in survival rates among biogeographic provinces or between populations that winter in either Central or South America. When data were pooled for a regional estimate of survivorship, the percent relative bias due to pooling 'locations' was <1%. With the pooled data, we estimated a 44% annual regional survival rate; this low estimated survival rate was likely due to the presence of transients in the population (Rosenberg and others 1999). Using simulated data, we found that power to detect spatial differences increased considerably with number of years and spatial scale, the latter reflecting larger sample size. Detection of trends at smaller spatial scales required > 12 years of monitoring. Detection of spatial patterns and temporal trends in survival rates from local to regional scales will provide important information for management and future research directed toward conservation of landbirds.

Book chapter↗
USGS1980

Influence of a local source of DDT pollution on statewide DDT residues in waterfowl wings, northern Alabama, 1978-79

Heavy DDT contamination resulting from a former DDT manufacturing plant in northern Alabama has influenced statewide averages of DDT, DDE, and TDE residues in duck wings tested in the National Pesticide Monitoring Program. In states where contaminant levels in duck wings are high, residue analyses of wings categorized by finer geographic subdivision may be useful in defining the areas of heaviest contamination.

Pesticides Monitoring Journal↗
USGS1991

Techniques and strategies for data integration in mineral resource assessment

The Geologic and the National Mapping divisions of the U.S. Geological Survey have been involved formally in cooperative research and development of computer-based geographic information systems (GISs) applied to mineral-resource assessment objectives since 1982. Experience in the Conterminous United States Mineral Assessment Program (CUSMAP) projects including the Rolla, Missouri; Dillon, Montana; Butte, Montana; and Tonopah, Nevada 1?? ?? 2?? quadrangles, has resulted in the definition of processing requirements for geographically and mineral-resource data that are common to these studies. The diverse formats of data sets collected and compiled for regional mineral-resource assessments necessitate capabilities for digitally encoding and entering data into appropriate tabular, vector, and raster subsystems of the GIS. Although many of the required data sets are either available or can be provided in a digital format suitable for direct entry, their utility is largely dependent on the original intent and consequent preprocessing of the data. In this respect, special care must be taken to ensure the digital data type, encoding, and format will meet assessment objectives. Data processing within the GIS is directed primarily toward the development and application of models that can be used to describe spatially geological, geophysical, and geochemical environments either known or inferred to be associated with specific types of mineral deposits. Consequently, capabilities to analyze spatially, aggregate, and display relations between data sets are principal processing requirements. To facilitate the development of these models within the GIS, interfaces must be developed among vector-, raster-, and tabular-based processing subsystems to reformat resident data sets for comparative analyses and multivariate display of relations.

Conference Paper↗
USGS2008

Avian Species Inventory at Manzanar National Historic Site, California - Final Report to the National Park Service

We conducted a baseline inventory for avian species at Manzanar National Historic Site, Inyo County, Calif., from 2002 to 2005. Under the guidelines of the Mojave Network Biological Inventory Program, the primary objectives for this study were to (1) inventory and document the occurrence of avian species at Manzanar, with the goal of documenting at least 90 percent of the species present; (2) provide a geographic information system (GIS)-referenced list of sensitive species occurring at Manzanar that are rare, on Federal or State lists, or otherwise worthy of special consideration; and (3) enter all species data into the National Park Service NPSpecies database. Survey methods included general area searches, variable circular plot point-count censusing, nocturnal surveys, and nest searching. During 13 year-round survey sessions, we documented the occurrence of 132 bird species at Manzanar and confirmed breeding by 19 of these. Based on our findings, as well as review of the literature and searches for records of species occurrence, we estimate inventory completeness for regularly occurring bird species at Manzanar to be near 90 percent. No sensitive species on Federal or State lists were found. The distribution and relative abundance of common bird species at this site is now well enough known to begin development of a monitoring protocol for this group.

Open-File Report↗
USGS2001

Statewide water-quality network for Massachusetts

A water-quality monitoring program is proposed that would provide data to meet multiple information needs of Massachusetts agencies and other users concerned with the condition of the State's water resources. The program was designed by the U.S. Geological Survey and the Massachusetts Department of Environmental Protection, Division of Watershed Management, with input from many organizations involved in water-quality monitoring in the State, and focuses on inland surface waters (streams and lakes). The proposed monitoring program consists of several components, or tiers, which are defined in terms of specific monitoring objectives, and is intended to complement the Massachusetts Watershed Initiative (MWI) basin assessments. Several components were developed using the Neponset River Basin in eastern Massachusetts as a pilot area, or otherwise make use of data from and sampling approaches used in that basin as part of a MWI pilot assessment in 1994. To guide development of the monitoring program, reviews were conducted of general principles of network design, including monitoring objectives and approaches, and of ongoing monitoring activities of Massachusetts State agencies.Network tiers described in this report are primarily (1) a statewide, basin-based assessment of existing surface-water-quality conditions, and (2) a fixed-station network for determining contaminant loads carried by major rivers. Other components, including (3) targeted programs for hot-spot monitoring and other objectives, and (4) compliance monitoring, also are discussed. Monitoring programs for the development of Total Maximum Daily Loads for specific water bodies, which would constitute another tier of the network, are being developed separately and are not described in this report. The basin-based assessment of existing conditions is designed to provide information on the status of surface waters with respect to State water-quality standards and designated uses in accordance with the reporting requirements [Section 305(b)] of the Clean Water Act (CWA). Geographic Information System (GIS)-based procedures were developed to inventory streams and lakes in a basin for these purposes. Several monitoring approaches for this tier and their associated resource requirements were investigated. Analysis of the Neponset Basin for this purpose demonstrated that the large number of sites needed in order for all the small streams in a basin to be sampled (about half of stream miles in the basin were headwater or first-order streams) pose substantial resource-based problems for a comprehensive assessment of existing conditions. The many lakes pose similar problems. Thus, a design is presented in which probabilistic monitoring of small streams is combined with deterministic or targeted monitoring of large streams and lakes to meet CWA requirements and to provide data for other information needs of Massachusetts regulatory agencies and MWI teams.The fixed-station network is designed to permit the determination of contaminant loads carried by the State's major rivers to sensitive inland and coastal receiving waters and across State boundaries. Sampling at 19 proposed sites in 17 of the 27 major basins in Massachusetts would provide information on contaminant loads from 67 percent of the total land area of the State; unsampled areas are primarily coastal areas drained by many small streams that would be impossible to sample within realistic resource limitations. Strategies for hot-spot monitoring, a targeted monitoring program focused on identifying contaminant sources, are described with reference to an analysis of the bacteria sampling program of the 1994 Neponset Basin assessment. Finally, major discharge sites permitted under the National Pollutant Discharge Elimination System (NPDES) were evaluated as a basis for ambient water-quality monitoring. The discharge sites are well distributed geographically among basins, but are primarily on large rivers (two-thirds or more

Water-Resources Investigations Report↗
USGS2013

Streamflow of 2012--Water year summary

The maps and graphs in this summary describe streamflow conditions for water year 2012 (October 1, 2011, to September 30, 2012) in the context of the 83-year period from 1930 through 2012, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930–2012 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term “runoff,” which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a specified time period was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation’s rivers and streams in measurement units that can be compared from one area to another.

Fact Sheet↗
USGS2014

Streamflow of 2013: Water year summary

The maps and graphs in this summary describe streamflow conditions for water year 2013 (October 1, 2012, to September 30, 2013) in the context of the 84-year period from 1930 through 2013, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Water Information System ( http://waterdata.usgs.gov/nwis/ ). The period 1930–2013 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term “runoff,” which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a specified time period was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation’s rivers and streams in measurement units that can be compared from one area to another.

Fact Sheet↗
USGS2016

Streamflow of 2015—Water year national summary

Introduction The maps and graphs in this summary describe national streamflow conditions for water year 2015 (October 1, 2014, to September 30, 2015) in the context of the 86-year period 1930–2015, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program http://water.usgs.gov/nsip ). The period 1930–2015 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term “runoff,” which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a specified time period was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs can be expanded to a larger view by clicking on the image. In all of the graphics, a rank of 1 indicates the highest flow of all years analyzed. Rankings of streamflow are grouped into much-below normal, below normal, normal, above normal, and much-above normal, based on percentiles of flow (greater than 90 percent, 76–90 percent, 25–75 percent, 10–24 percent, and less than 10 percent, respectively) ( http://waterwatch.usgs.gov/?id=ww_current ). Some data used to produce maps and graphs are provisional and subject to change.

Fact Sheet↗
USGS2009

Land-Cover Change in the East Central Texas Plains, 1973-2000

Project Background: The Geographic Analysis and Monitoring (GAM) Program of the U.S. Geological Survey (USGS) Land Cover Trends project is focused on understanding the rates, trends, causes, and consequences of contemporary U.S. land-use and land-cover change. The objectives of the study are to: (1) develop a comprehensive methodology for using sampling and change analysis techniques and Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) data for measuring regional land-cover change across the United States, (2) characterize the types, rates and temporal variability of change for a 30-year period, (3) document regional driving forces and consequences of change, and (4) prepare a national synthesis of land-cover change (Loveland and others, 1999). Using the 1999 Environmental Protection Agency (EPA) Level III ecoregions derived from Omernik (1987) as the geographic framework, geospatial data collected between 1973 and 2000 were processed and analyzed to characterize ecosystem responses to land-use changes. The 27-year study period was divided into five temporal periods: 1973-1980, 1980-1986, 1986-1992, 1992-2000, and 1973-2000. General land-cover classes such as water, developed, grassland/shrubland, and agriculture for these periods were interpreted from Landsat MSS, TM, and Enhanced Thematic Mapper Plus imagery to categorize land-cover change and evaluate using a modified Anderson Land-Use Land-Cover Classification System for image interpretation. The interpretation of these land-cover classes complement the program objective of looking at land-use change with cover serving as a surrogate for land use. The land-cover change rates are estimated using a stratified, random sampling of 10-kilometer (km) by 10-km blocks allocated within each ecoregion. For each sample block, satellite images are used to interpret land-cover change for the five time periods previously mentioned. Additionally, historical aerial photographs from similar timeframes and other ancillary data such as census statistics and published literature are used. The sample block data are then incorporated into statistical analyses to generate an overall change matrix for the ecoregion. For example, the scalar statistics can show the spatial extent of change per cover type with time, as well as the land-cover transformations from one land-cover type to another type occurring with time. Field data of the sample blocks include direct measurements of land cover, particularly ground-survey data collected for training and validation of image classifications (Loveland and others, 2002). The field experience allows for additional observations of the character and condition of the landscape, assistance in sample block interpretation, ground truthing of Landsat imagery, and helps determine the driving forces of change identified in an ecoregion. Management and maintenance of field data, beyond initial use for training and validation of image classifications, is important as improved methods for image classification are developed, and as present-day data become part of the historical legacy for which studies of land-cover change in the future will depend (Loveland and others, 2002). The results illustrate that there is no single profile of land-cover change; instead, there is significant geographic variability that results from land uses within ecoregions continuously adapting to the resource potential created by various environmental, technological, and socioeconomic factors.

Open-File Report↗
USGS2015

Agencies collaborate, develop a cyanobacteria assessment network

Cyanobacteria are a genetically diverse group of photosynthetic microorganisms that occupy a broad range of habitats on land and water all over the world. They release toxins that can cause lung and skin irritation, alter the taste and odor of potable water, and cause human and animal illness. Cyanobacteria blooms occur worldwide, and climate change may increase the frequency, duration, and extent of these bloom events. Rapid detection of potentially harmful blooms is essential to protect humans and animals from exposure. Information about potential for exposure, such as bloom duration, frequency, and extent, is especially critical for developing environmental management decisions during periods of limited resources and funding. The National Research Council (NRC) report Exposure Science in the 21st Century suggested that effectively assessing and mitigating exposures requires techniques for rapid measurement of a stressor, such as an algal bloom, across diverse geographic, temporal, and biologic scales (e.g., various bloom concentrations) and an enhanced infrastructure to address threats [ NRC , 2012]. The report specifically calls for approaches that use diverse information, such as satellite remote sensing, to identify and understand exposures that may pose a threat to ecosystems or human health. A collaborative effort integrates the work of the U.S. Environmental Protection Agency (EPA), NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey (USGS) to provide an approach for using satellite ocean color capabilities in U.S. fresh and brackish water quality management decisions. The overarching goal of this collaborative project is to detect and quantify cyanobacteria blooms using satellite data records in order to support the environmental management and public use of U.S. lakes and reservoirs. Satellite remote sensing tools may enable policy makers and environmental managers to assess the sustainability of watershed ecosystems and the services they provide, now and in the future. Satellite technology allows us to develop early-warning indicators of cyanobacteria blooms at the local scale while maintaining continuous national coverage.

Eos, Earth and Space Science News↗
USGS2023

Skinks of Oceania, New Guinea, and Eastern Wallacea: An underexplored biodiversity hotspot

Context: Skinks comprise the dominant component of the terrestrial vertebrate fauna in Oceania, New Guinea, and Eastern Wallacea (ONGEW). However, knowledge of their diversity is incomplete, and their conservation needs are poorly understood. Aims: To explore the diversity and threat status of the skinks of ONGEW and identify knowledge gaps and conservation needs. Methods: We compiled a list of all skink species occurring in the region and their threat categories designated by the International Union for Conservation of Nature. We used available genetic sequences deposited in the National Center for Biotechnology Information’s GenBank to generate a phylogeny of the region’s skinks. We then assessed their diversity within geographical sub-divisions and compared to other reptile taxa in the region. Key results: Approximately 300 species of skinks occur in ONGEW, making it the second largest global hotspot of skink diversity following Australia. Many phylogenetic relationships remain unresolved, and many species and genera are in need of taxonomic revision. One in five species are threatened with extinction, a higher proportion than almost all reptile families in the region. Conclusions: ONGEW contain a large proportion of global skink diversity on <1% of the Earth’s landmass. Many are endemic and face risks such as habitat loss and invasive predators. Yet, little is known about them, and many species require taxonomic revision and threat level re-assessment. Implications: The skinks of ONGEW are a diverse yet underexplored group of terrestrial vertebrates, with many species likely facing extreme risks in the near future. Further research is needed to understand the threats they face and how to protect them.

Pacific Conservation Biology↗