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At least 559 records · Page 31Linked to original sources
USGS2010

Attributes for MRB_E2RF1 Catchments in Selected Major River Basins of the Conterminous United States: Contact Time, 2002

This tabular data set represents the average contact time, in units of days, compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others, 2006). Contact time, as described in Vitvar and others (2002), is defined as the baseflow residence time in the subsurface. The source data set was the U.S. Geological Survey's (USGS) 1-kilometer grid for the conterminous United States (D.M. Wolock, U.S. Geological Survey, written commun., 2008). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) RF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Data Series↗
USGS2015

Hydrogeology, hydrologic effects of development, and simulation of groundwater flow in the Borrego Valley, San Diego County, California

Executive Summary The Borrego Valley is a small valley (110 square miles) in the northeastern part of San Diego County, California. Although the valley is about 60 miles northeast of city of San Diego, it is separated from the Pacific Ocean coast by the mountains to the west and is mostly within the boundaries of Anza-Borrego Desert State Park. From the time the basin was first settled, groundwater has been the only source of water to the valley. Groundwater is used for agricultural, recreational, and municipal purposes. Over time, groundwater withdrawal through pumping has exceeded the amount of water that has been replenished, causing groundwater-level declines of more than 100 feet in some parts of the basin. Continued pumping has resulted in an increase in pumping lifts, reduced well efficiency, dry wells, changes in water quality, and loss of natural groundwater discharge. As a result, the U.S. Geological Survey began a cooperative study of the Borrego Valley with the Borrego Water District (BWD) in 2009. The purpose of the study was to develop a greater understanding of the hydrogeology of the Borrego Valley Groundwater Basin (BVGB) and to provide tools to help evaluate the potential hydrologic effects of future development. The objectives of the study were to (1) improve the understanding of groundwater conditions and land subsidence, (2) incorporate this improved understanding into a model that would assist in the management of the groundwater resources in the Borrego Valley, and (3) use this model to test several management scenarios. This model provides the capability for the BWD and regional stakeholders to quantify the relative benefits of various options for increasing groundwater storage. The study focuses on the period 1945–2010, with scenarios 50 years into the future. This report documents and presents (1) an analysis of the conceptual model, (2) a description of the hydrologic features, (3) a compilation and analysis of water-quality data, (4) the measurement and analysis of land subsidence by using geophysical and remote sensing techniques, (5) the development and calibration of a two-dimensional borehole-groundwater-flow model to estimate aquifer hydraulic conductivities, (6) the development and calibration of a three-dimensional (3-D) integrated hydrologic flow model, (7) a water-availability analysis with respect to current climate variability and land use, and (8) potential future management scenarios. The integrated hydrologic model, referred to here as the “Borrego Valley Hydrologic Model” (BVHM), is a tool that can provide results with the accuracy needed for making water-management decisions, although potential future refinements and enhancements could further improve the level of spatial and temporal resolution and model accuracy. Because the model incorporates time-varying inflows and outflows, this tool can be used to evaluate the effects of temporal changes in recharge and pumping and to compare the relative effects of different water-management scenarios on the aquifer system. Overall, the development of the hydrogeologic and hydrologic models, data networks, and hydrologic analysis provides a basis for assessing surface and groundwater availability and potential water-resource management guidelines.

California↗
USGS1983

Water resources data for Hawaii and other Pacific areas, water year 1982: Volume 1. Hawaii

Water resources data for the 1982 water year for Hawaii and other Pacific Areas consist of records of stage, discharge, and water quality of streams and springs; and water levels and water quality in wells. This report, volume 1, contains discharge records for 106 gaging stations; water quality for 11 gaging stations, 95 partial-record flaw stations, and 152 wells; and water levels for 21 observation wells. Also included are 108 crest-stage partial-record stations and 15 low-flow partial-record stations. Additional water data were collected at various sites, not part of the systematic data collection program, are published as miscellaneous measurements. These data represent that part of- the National Water Data System operated by the U.S. Geological Survey and cooperating State, Federal, and other agencies in Hawaii.

Hawaii↗
USGS1986

Water resources data for Hawaii and other Pacific areas, water year 1985: Volume 1. Hawaii

Water resources data for the 1985 water year for Hawaii and other Pacific Areas consist of records of stage, discharge, and water quality of streams and springs; and water levels and water quality in wells. This report, volume 1, contains discharge records for 98 gaging stations; water quality for 13 gaging stations, 100 partial-record flow stations, and 154 wells; and water levels for 39 observation wells. Also included are 108 crest-stage partial-record stations and 20 low-flow partial-record stations. Additional water data were collected at various sites, not part of the systematic data collection program, are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, Federal, and other agencies in Hawaii.

Hawaii↗
USGS1984

NONFUEL MINERAL RESOURCES OF THE PACIFIC EXCLUSIVE ECONOMIC ZONE.

The Pacific Exclusive Economic Zone contains a variety of hard mineral resources. Sand and gravel and their associated placer deposits of heavy minerals are the most likely to be developed in the near future, but offshore and deep water deposits of phosphorite, abyssal manganese nodules, ferromanganese crusts enriched in cobalt, and massive sulfide deposits all represent future resources. The distribution, extent, and formation of these deposits are poorly understood and will be clarified only with additional exploration, framework geologic mapping, and study of the processes by which these resources form. It is pointed out that the initial discovery of most hard-mineral resources in the EEZ was made during routine scientific marine-geologic surveys aimed at understanding the framework geology and geologic processes of an offshore region.

Conference Paper↗
USGS2018

Survival, travel time, and utilization of Yolo Bypass, California, by outmigrating acoustic-tagged late-fall Chinook salmon

Juvenile Chinook salmon ( Oncorhynchus tshawytscha ) migrating through California's Sacramento-San Joaquin River Delta toward the Pacific Ocean face numerous challenges to their survival. The Yolo Bypass is a broad floodplain of the Sacramento River that floods in about 70 percent of years in response to large, uncontrolled runoff events. As one of the routes juvenile salmon may utilize, the Yolo Bypass has recently received attention for having potential benefit to rearing and migrating salmon. Consideration is being given to a plan to build a cut or “notch” in the Fremont Weir to increase juvenile salmon access to the Yolo Bypass. To help provide information about the potential benefit of such a plan, we analyzed data from a telemetry study conducted in February and March 2016 by the U.S. Geological Survey and California Department of Water Resources to estimate entrainment into and distribution of juvenile Chinook salmon within the Yolo Bypass, and to compare survival and travel time through the Yolo Bypass to other routes in the Delta. We also estimated juvenile Chinook salmon survival through three short reaches of the Sacramento River where the proposed California WaterFix North Delta Diversion intakes would divert water to export facilities to provide baseline information against which any effects of those intakes could be measured in the future. We found that entrainment into the Yolo Bypass varied widely and was quite high only at the peak of the March 2016 flood. Spatial distribution of juvenile Chinook salmon within the Yolo Bypass was fairly even for fish entering the Yolo Bypass over the Fremont Weir, but increasingly skewed toward the east bank for fish released within the Yolo Bypass. Survival within Yolo Bypass was not significantly different for fish based on spatial distribution. Survival through the Delta for fish migrating through the Yolo Bypass was generally on par with the weighted survival through the Delta of fish migrating through all other routes. Survival was highest for fish remaining in the Sacramento River and lowest for those entrained into the Interior Delta via Georgiana Slough. Survival through the short section of the Sacramento River near the proposed North Delta Diversion intakes was high.

California↗
USGS2007

Dissolved solids in basin-fill aquifers and streams in the southwestern United States

The U.S. Geological Survey National Water-Quality Assessment Program performed a regional study in the Southwestern United States (Southwest) to describe the status and trends of dissolved solids in basin-fill aquifers and streams and to determine the natural and human factors that affect dissolved solids. Basin-fill aquifers, which include the Rio Grande aquifer system, Basin and Range basin-fill aquifers, and California Coastal Basin aquifers, are the most extensively used ground-water supplies in the Southwest. Rivers, such as the Colorado, the Rio Grande, and their tributaries, are also important water supplies, as are several smaller river systems that drain internally within the Southwest, or drain externally to the Pacific Ocean in southern California. The study included four components that characterize (1) the spatial distribution of dissolved-solids concentrations in basin-fill aquifers, and dissolved-solids concentrations, loads, and yields in streams; (2) natural and human factors that affect dissolved-solids concentrations; (3) major sources and areas of accumulation of dissolved solids; and (4) trends in dissolved-solids concentrations over time in basin-fill aquifers and streams, and the relation of trends to natural or human factors.

Arizona, California, Colorado, Idaho, Nevada, New ↗
USGS2000

Ground-water resources of Tinian, Commonwealth of the Northern Mariana Islands

Tinian, which lies in the western Pacific Ocean at latitude 15°N and longitude 145°W (fig. 1), is the second largest island (39.2 mi 2 ) in the Commonwealth of the Northern Mariana Islands (CNMI). Fresh ground water is obtained from shallow wells that tap the surface of a freshwater lends found in an aquifer composed mainly of coralline limestone. The main water-supply well withdraws water with a chloride concentration ranging from 160 to 220 mg/L. Current (1999) pumping rates adequately supply the island residents but future demand are expected to be higher.. To better understand the ground-water resources of the island and to learn more about the hydrology of oceanic islands, the U.S. Geological Survey (USGS) entered into a cooperative study with the Municipality of Tinian. The objective of the study, conducted between 1990 and 1997, was to assess the ground-water resources of the is;land. This report presents some of the results of the study including a description of the island's geology and geography, the current land use, the water-production system, the thickness and arcal extent of the freshwater lens, the water-table configuration and directions of ground-water flow. The report also discusses the relation of the changes in water-table elevation to daily and seasonal changes in ocean level.

Tinian Island↗
USGS2009

Optical satellite data volcano monitoring: a multi-sensor rapid response system

In this chapter, the use of satellite remote sensing to monitor active geological processes is described. Specifically, threats posed by volcanic eruptions are briefly outlined, and essential monitoring requirements are discussed. As an application example, a collaborative, multi-agency operational volcano monitoring system in the north Pacific is highlighted with a focus on the 2007 eruption of Kliuchevskoi volcano, Russia. The data from this system have been used since 2004 to detect the onset of volcanic activity, support the emergency response to large eruptions, and assess the volcanic products produced following the eruption. The overall utility of such integrative assessments is also summarized. The work described in this chapter was originally funded through two National Aeronautics and Space Administration (NASA) Earth System Science research grants that focused on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. A skilled team of volcanologists, geologists, satellite tasking experts, satellite ground system experts, system engineers and software developers collaborated to accomplish the objectives. The first project, Automation of the ASTER Emergency Data Acquisition Protocol for Scientific Analysis, Disaster Monitoring, and Preparedness , established the original collaborative research and monitoring program between the University of Pittsburgh (UP), the Alaska Volcano Observatory (AVO), the NASA Land Processes Distributed Active Archive Center (LP DAAC) at the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center, and affiliates on the ASTER Science Team at the Jet Propulsion Laboratory (JPL) as well as associates at the Earth Remote Sensing Data Analysis Center (ERSDAC) in Japan. This grant, completed in 2008, also allowed for detailed volcanic analyses and data validation during three separate summer field campaigns to Kamchatka Russia. The second project, Expansion and synergistic use of the ASTER Urgent Request Protocol (URP) for natural disaster monitoring and scientific analysis , has expanded the project to other volcanoes around the world and is in progress through 2011. The focus on ASTER data is due to the suitability of the sensor for natural disaster monitoring and the availability of data. The instrument has several unique facets that make it especially attractive for volcanic observations (Ramsey and Dehn, 2004). Specifically, ASTER routinely collects data at night, it has the ability to generate digital elevation models using stereo imaging, it can collect data in various gain states to minimize data saturation, it has a cross-track pointing capability for faster targeting, and it collects data up to ±85° latitude for better global coverage. As with any optical imaging-based remote sensing, the viewing conditions can negatively impact the data quality. This impact varies across the optical and thermal infrared wavelengths as well as being a function of the specific atmospheric window within a given wavelength region. Water vapor and cloud formation can obscure surface data in the visible and near infrared (VNIR)/shortwave infrared (SWIR) region due mainly to non-selective scattering of the incident photons. In the longer wavelengths of the thermal infrared (TIR), scattering is less of an issue, but heavy cloud cover can still obscure the ground due to atmospheric absorption. Thin clouds can be optically-transparent in the VNIR and TIR regions, but can cause errors in the extracted surface reflectance or derived surface temperatures. In regions prone to heavy cloud cover, optical remote sensing can be improved through increased temporal resolution. As more images are acquired in a given time period the chances of a clear image improve dramatically. The Advanced Very High Resolution Radiometer (AVHRR) routine monitoring, which commonly collects 4-6 images per day of any north Pacific volcano, takes advantage of this fact. The rapid response program described in this chapter also improves the temporal resolution of the ASTER instrument. ASTER has been acquiring images of volcanic eruptions since soon after its launch in December 1999. An early example included the observations of the large pyroclastic flow deposit emplaced at Bezymianny volcano in Kamchatka, Russia. The first images in March 2000, just weeks after the eruption, revealed the extent, composition, and cooling history of this large deposit and of the active lava dome (Ramsey and Dehn, 2004). The initial results from these early datasets spurred interest in using ASTER data for expanded volcano monitoring in the north Pacific. It also gave rise to the multi-year NASA-funded programs of rapid response scheduling and imaging throughout the Aleutian, Kamchatka and Kurile arcs. Since the formal establishment of the programs, the data have provided detailed descriptions of the eruptions of Augustine, Bezymianny, Kliuchevskoi and Sheveluch volcanoes over the past nine years (Wessels et al., in press; Carter et al., 2007, 2008; Ramsey et al., 2008; Rose and Ramsey, 2009). The initial research focus of this rapid response program was specifically on automating the ASTER sensor’s ability for targeted observational scheduling using the expedited data system. This urgent request protocol is one of the unique characteristics of ASTER. It provides a limited number of emergency observations, typically at a much-improved temporal resolution and quicker turnaround with data processing in the United States rather than in Japan. This can speed the reception of the processed data by several days to a week. The ongoing multi-agency research and operational collaboration has been highly successful. AVO serves as the primary source for status information on volcanic activity, working closely with the National Weather Service (NWS), Federal Aviation Administration (FAA), military and other state and federal emergency services. Collaboration with the Russian Institute of Volcanology and Seismology (IVS)/Kamchatka Volcanic Eruption Response Team (KVERT) is also maintained. Once a volcano is identified as having increased thermal output, ASTER is automatically tasked and the volcano is targeted at the next available opportunity. After the data are acquired, scientists at all the agencies have access to the images, with the primary science analysis carried out at the University of Pittsburgh and AVO. Results are disseminated to the responsible monitoring agencies and the global community through e-mail mailing lists.

Book chapter↗
USGS2016

Who Knew? Inconnu

In 1999, I moved to Alaska to serve as unit leader of the U.S. Geological Survey Alaska Cooperative Fish and Wildlife Research Unit and professor of fisheries in the School of Fisheries and Ocean Sciences at the University of Alaska Fairbanks. What was unusual about this move was that before this I was an easterner and southerner, having done my graduate work in fisheries at Texas A&M University and been stationed in the Coop Unit Program in Ohio, West Virginia, and Maryland. I had never worked with salmonids of any sort. To me fish with adipose fins also had whiskers! I suddenly found myself working in the land of salmon experts, and I didn't even reliably know the names—scientific, common, or colloquial—of the five (or is it six?) common Pacific salmon species in Alaska. I had to quickly find a research niche that probably didn't involve salmon.

Fisheries↗
USGS2006

National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast

Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive analysis of shoreline movement that is consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the conterminous United States and parts of Hawaii and Alaska. One purpose of this work is to develop standard repeatable methods for mapping and analyzing shoreline movement so that periodic updates regarding coastal erosion and land loss can be made nationally that are systematic and internally consistent. In the case of this study, the shoreline being measured is the boundary between the ocean water surface and the sandy beach. This report on the California Coast represents the first of two reports on long-term sandy shoreline change for the western U.S., the second of which will include the coast of the Pacific NW, including Oregon and Washington. A report for the Gulf of Mexico shoreline was completed in 2004 and is available at: http://pubs.usgs.gov/of/2004/1043/. This report summarizes the methods of analysis, interprets the results, provides explanations regarding long-term and short-term trends and rates of change, and describes how different coastal communities are responding to coastal erosion. Shoreline change evaluations are based on comparing three historical shorelines digitized from maps, with a recent shoreline derived from lidar (Light Detection and Ranging) topographic surveys. The historical shorelines generally represent the following periods: 1800s, 1920s-1930s, and 1950s-1970s, whereas the lidar shoreline is from 1998-2002. Long-term rates of change are calculated using all four shorelines (1800s to lidar shoreline), whereas short-term rates of change are calculated for only the most recent period (1950s-1970s to lidar shoreline). The rates of change presented in this report represent past conditions and therefore are not intended for predicting future shoreline positions or rates of change. Due to the geomorphology of the California Coast (rocky coastline instead of beach) as well as to data gaps in some areas, this report presents beach erosion rates for 45% of California's 1100 km of coast. The average rate of long-term shoreline change for the State of California was 0.2?0.1 m/yr, an accretional trend. This is based on shoreline change rates averaged from 14,562 individual transects, of which 40% were eroding. Of the transects on which the shoreline was eroding, the long-term erosion rates were generally lowest in Southern California where coastal engineering projects have greatly altered the natural shoreline movement. On a regional scale, long-term accretion rates were either equal to (Central California) or greater than (Northern and Southern California) the long-term erosion rates, yielding the net accretional trend for the entire state. This accretional trend is most likely due to changes in the large volumes of sediment that are added to the system from large rivers and to the impact from coastal engineering and beach nourishment projects. The average rate of short-term shoreline change for the state was erosional. The net short-term rate as averaged along 16,142 transects was -0.2?0.4 m/yr. Of the transects used to measure short-term change, 66% had erosional trends. In addition erosion rates were higher in the short-term period, possibly related to the localized artificial nourishment that occurred over much of the 20th century but that has recently slowed or stopped (Flick, 1993; Wiegel, 1994). Short-term accretion rates were highest in Northern California where the overall magnitudes of shoreline change are systematically higher than in Central and Southern California. The most stable (low erosion and accretion rates) California beaches were most commonly found in Central California. Seawalls and/or riprap revetments have been constructed in all three sections of California, although many of these structures were built to protect houses and infrastructures from the erosion of coastal cliffs and bluffs rather than to protect against long-term beach erosion. California permits shoreline stabilization structures where homes, buildings or other community infrastructure are imminently threatened by erosion. A second California report that is following this publication will include analyses and reports on long-term coastal cliff erosion, as this hazard is of equal or greater concern to coastal communities in many areas along the California Coast.

Open-File Report↗
USGS2006

Under the Golden Gate Bridge — Views of the sea floor near the entrance to San Francisco Bay, California

San Francisco Bay in Northern California is one of the largest and most altered estuaries within the United States. The sea floor within the bay as well as at its entrance is constantly changing due to strong tidal currents, aggregate mining, dredge disposal, and the creation of new land using artificial fill. Understanding this dynamic sea floor is critical for addressing local environmental issues, which include defining pollution transport pathways, deciphering tectonics, and identifying benthic habitats. Mapping commercial interests such as safe ship navigation and dredge disposal is also significantly aided by such understanding. Over the past decade, the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), and California State University, Monterey Bay (CSUMB) in cooperation with the U.S. Army Corps of Engineers (USACOE) and the Center for Integrative Coastal Observation, Research and Education (CICORE) have partnered to map central San Francisco Bay and its entrance under the Golden Gate Bridge using multibeam echosounders. These sonar systems can continuously map to produce 100 percent coverage of the sea floor at meter-scale resolution and thus produce an unprecedented view of the floor of the bay. This poster shows views of the sea floor in west-central San Francisco Bay around Alcatraz and Angel Islands, underneath the Golden Gate Bridge, and through its entrance from the Pacific Ocean. The sea floor is portrayed as a shaded relief surface generated from the multibeam data color-coded for depth from light blues for the shallowest values to purples for the deepest. The land regions are portrayed by USGS digital orthophotographs (DOQs) overlaid on USGS digital elevation models (DEMs). The water depths have a 4x vertical exaggeration while the land areas have a 2x vertical exaggeration.

California↗
USGS2012

A basin-scale approach for assessing water resources in a semiarid environment: San Diego region, California and Mexico

Many basins throughout the world have sparse hydrologic and geologic data, but have increasing demands for water and a commensurate need for integrated understanding of surface and groundwater resources. This paper demonstrates a methodology for using a distributed parameter water-balance model, gaged surface-water flow, and a reconnaissance-level groundwater flow model to develop a first-order water balance. Flow amounts are rounded to the nearest 5 million cubic meters per year. The San Diego River basin is 1 of 5 major drainage basins that drain to the San Diego coastal plain, the source of public water supply for the San Diego area. The distributed parameter water-balance model (Basin Characterization Model) was run at a monthly timestep for 1940–2009 to determine a median annual total water inflow of 120 million cubic meters per year for the San Diego region. The model was also run specifically for the San Diego River basin for 1982–2009 to provide constraints to model calibration and to evaluate the proportion of inflow that becomes groundwater discharge, resulting in a median annual total water inflow of 50 million cubic meters per year. On the basis of flow records for the San Diego River at Fashion Valley (US Geological Survey gaging station 11023000), when corrected for upper basin reservoir storage and imported water, the total is 30 million cubic meters per year. The difference between these two flow quantities defines the annual groundwater outflow from the San Diego River basin at 20 million cubic meters per year. These three flow components constitute a first-order water budget estimate for the San Diego River basin. The ratio of surface-water outflow and groundwater outflow to total water inflow are 0.6 and 0.4, respectively. Using total water inflow determined using the Basin Characterization Model for the entire San Diego region and the 0.4 partitioning factor, groundwater outflow from the San Diego region, through the coastal plain aquifer to the Pacific Ocean, is calculated to be approximately 50 million cubic meters per year. The area-scale assessment of water resources highlights several hydrologic features of the San Diego region. Groundwater recharge is episodic; the Basin Characterization Model output shows that 90 percent of simulated recharge occurred during 3 percent of the 1982–2009 period. The groundwater aquifer may also be quite permeable. A reconnaissance-level groundwater flow model for the San Diego River basin was used to check the water budget estimates, and the basic interaction of the surface-water and groundwater system, and the flow values, were found to be reasonable. Horizontal hydraulic conductivity values of the volcanic and metavolcanic bedrock in San Diego region range from 1 to 10 m per day. Overall, results establish an initial hydrologic assessment formulated on the basis of sparse hydrologic data. The described flow variability, extrapolation, and unique characteristics represent a realistic view of current (2012) hydrologic understanding for the San Diego region.

California↗
USGS2022

Attribution of monotonic trends and change points in peak streamflow across the conterminous United States using a multiple working hypotheses framework, 1941–2015 and 1966–2015

The U.S. Geological Survey has a long history of leading flood-frequency analysis studies. These studies play a critical role in the assessment of risk, protection of lives, and planning and design of flood protection infrastructure. Standard flood-frequency analysis is based on the assumption of stationarity—that is, that the distribution of floods at a given site varies around a particular mean within a particular envelope of variance (and skew) and that these parameters of the underlying statistical distribution representative of the floods do not vary over time. Gradual or abrupt changes in one or more of the distributional parameters are called nonstationarities and violate the underlying assumptions of current U.S. Federal Government guidelines for flood-frequency analysis. Uncertainty exists as to what degree of violations calls for the use of a modified method for flood-frequency analysis and what the modified method(s) should be. When deciding whether to perform nonstationary flood-frequency analysis and choosing a method for such analysis, it is important to understand the causes of the nonstationarity. Gradual or abrupt changes in distributional properties of floods may be the result of numerous factors, such as regulation, diversion, land-use change, or climate change. In the interest of developing a cohesive national approach for better understanding the causes of nonstationarities and incorporating potential or observed changes into flood-frequency estimates, subject-matter experts from the U.S. Geological Survey and cooperators worked together to develop a multiple working hypotheses framework for making attributions and a common vocabulary for making provisions of confidence. Seven regional teams of these experts used ancillary datasets and institutional knowledge to evaluate plausible causes for monotonic trends and change points in annual peak-streamflow data for the conterminous United States that had been identified in an earlier phase of the project. The first chapter of this professional paper describes the development of a list of the potential attributions, presents a literature review of the potential attributions, describes the regional approach, summarizes insights obtained from the attribution process, and suggests future research. The other chapters provide the methods used for attribution in the seven regions—Pacific Northwest, Upper Plains, Midwest, Northeast, Southwest, South-Central, and Southeast—and summarize the regional patterns of nonstationarities.

Conterminous United States↗
USGS2012

U.S. Geological Survey, National Wildlife Health Center, 2011 report of selected wildlife diseases

The National Wildlife Health Center (NWHC) was founded in 1975 to provide technical assistance in identifying, controlling, and preventing wildlife losses from diseases, conduct research to understand the impact of diseases on wildlife populations, and devise methods to more effectively manage these disease threats. The impetus behind the creation of the NWHC was, in part, the catastrophic loss of tens of thousands of waterfowl as a result of an outbreak of duck plague at the Lake Andes National Wildlife Refuge in South Dakota during January 1973. In 1996, the NWHC, along with other Department of Interior research functions, was transferred from the U.S. Fish and Wildlife Service to the U.S. Geological Survey (USGS), where we remain one of many entities that provide the independent science that forms the bases of the sound management of the Nation’s natural resources. Our mission is to provide national leadership to safeguard wildlife and ecosystem health through dynamic partnerships and exceptional science. The main campus of the NWHC is located in Madison, Wis., where we maintain biological safety level 3 (BSL–3) diagnostic and research facilities purposefully designed for work with wildlife species. The NWHC provides research and technical assistance on wildlife health issues to State, Federal, and international agencies. In addition, since 1992 we have maintained a field station in Hawaii, the Honolulu Field Station, which focuses on marine and terrestrial natural resources throughout the Pacific region. The NWHC conducts diagnostic investigations of unusual wildlife morbidity and mortality events nationwide to detect the presence of wildlife pathogens and determine the cause of death. This is also an important activity for detecting new, emerging and resurging diseases. The NWHC provides this crucial information on the presence of wildlife diseases to wildlife managers to support sound management decisions. The data and information generated also allows for further indepth analyses for determining the biological and ecological significance of disease events, detecting disease trends over time and space, as well as detecting any significant changes to how diseases manifest in the field. Moreover, this information allows us to gain insight into the significance of future wildlife disease events. The purpose of this report is to provide a sample of NWHC data that are available from our Laboratory Information Management System (LIMS). These data are presented in summary format with minimal statistical analysis and interpretation. The goal is to share these data with wildlife managers and other stakeholders, promote the use of NHWC data, and encourage the sharing of wildlife disease data to improve temporal and geographic surveillance coverage. Continued national surveillance for wildlife diseases is essential for providing early detection and warning of events that have the potential to result in harm to human health, economic losses, declines in wildlife populations, and subsequent ecological disturbances. Increased collaboration, coordination, and sharing of surveillance data will enhance this Nation’s ability to detect and respond to wildlife disease threats.

Scientific Investigations Report↗
USGS1977

Petrology of basalt from the East Pacific Rise near 21 degrees North latitude

Four dredge hauls of fresh tholeiitic basalt lava were recovered from a 3.3-kilometer-wide zone at the axis of the East Pacific Rise. Petrologic and major-element chemical studies indicate that the basalt ranges from moderately fractionated varieties to one sample enriched in iron and titanium. The four samples show no symmetrical compositional zonation across the ridge axis, but the two least fractionated and youngest samples occur on the east side of the ridge axis.

Journal of Research of the U.S. Geological Survey↗
USGS2018

Geoelectric hazard maps for the Pacific Northwest

Maps of extreme value, horizontal component geoelectric field amplitude are constructed for the Pacific Northwest United States (and parts of neighboring Canada). Multidecade long geoelectric field time series are calculated by convolving Earth surface impedance tensors from 71 discrete magnetotelluric survey sites across the region with historical 1‐min (2‐min Nyquist) geomagnetic variation time series obtained from two nearby observatories. After fitting statistical models to 1‐min geoelectric amplitudes realized during magnetic storms, extrapolations are made to estimate threshold amplitudes that are only exceeded, on average, once per century. One hundred‐year geoelectric exceedance amplitudes range from 0.06 V/km at a survey site in western Washington State to 9.47 V/km at a site in southeast British Columbia; 100‐year geoelectric exceedance amplitudes equal 7.10 V/km at a site north of Seattle and 2.28 V/km at a site north of Portland. Systematic and random errors are estimated to be less than 20%, much less than site‐to‐site differences in geoelectric amplitude that arise from site‐to‐site differences in surface impedance. Maps of 100‐year exceedance amplitudes are compared with the peak geoelectric amplitudes realized during the March 1989 magnetic superstorm; it is noted that some storms of relatively modest intensity can generate localized geoelectric fields of relatively high amplitude. The geography of geoelectric hazard across the Pacific Northwest is closely related to known geologic and tectonic structures.

Pacific Northwest↗
USGS1988

Codes for the identification of aquifer names and geologic units in the United States and the Caribbean outlying areas

This standard provides codes to be used for the identification of aquifer names and geologic units in the United States, the Caribbean and other outlying areas. Outlying areas include Puerto Rico, the Virgin Islands, American Samoa, the Midway Islands, Trust Territories of the Pacific Islands, and miscellaneous Pacific Islands. Each code identifies an aquifer or rock-stratigraphic unit and its age designation. The codes provide a standardized base for use by organizations in the storage, retrieval, and exchange of ground-water data; the indexing and inventory of ground-water data and information; the cataloging of ground-water data acquisition activities; and a variety of other applications.

Circular↗