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Reports

Browse more than 82,000 reports authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.

Filter Total Items: 84799

Demography and population status of polar bears in western Hudson Bay Demography and population status of polar bears in western Hudson Bay

We evaluated the demography and population status of the Western Hudson Bay (WH) polar bear subpopulation for the period 1984-2011, using live-recapture data from research studies and management actions, and dead-recovery data from polar bears harvested for subsistence purposes or removed during human-bear conflicts. We used a Bayesian implementation of multistate capture-recapture...
Authors
Nicholas J. Lunn, Eric V Regher, Sabrina Servanty, Sarah J. Converse, Evan S. Richardson, Ian Stirling

Development of CE-QUAL-W2 models for the Middle Fork Willamette and South Santiam Rivers, Oregon Development of CE-QUAL-W2 models for the Middle Fork Willamette and South Santiam Rivers, Oregon

Hydrodynamic (CE-QUAL-W2) models of Hills Creek Lake (HCL), Lookout Point Lake (LOP), and Dexter Lake (DEX) on the Middle Fork Willamette River (MFWR), and models of Green Peter Lake and Foster Lake on the South Santiam River systems in western Oregon were updated and recalibrated for a wide range of flow and meteorological conditions. These CE-QUAL-W2 models originally were developed by...
Authors
Norman L. Buccola, Adam J. Stonewall, Annett B. Sullivan, Yoonhee Kim, Stewart A. Rounds

Effect of simulated tree canopy removal on a municipal wellfield in the Puget Sound aquifer system, Thurston County, Washington Effect of simulated tree canopy removal on a municipal wellfield in the Puget Sound aquifer system, Thurston County, Washington

Effects of tree canopy removal on a wellfield were simulated using a groundwater flow model characteristic of hydrogeologic settings in the Puget Sound aquifer system. Effects were estimated according to simulated changes in flow patterns that may result from tree canopy removal associated with varying degrees of residential development. The flow model used was a modified version of a...
Authors
Kenneth H. Johnson

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

This study documents the effects of acidic deposition and soil acid-base chemistry on the growth, regeneration, and canopy condition of sugar maple (SM) trees in the Adirondack Mountains of New York. Sugar maple is the dominant canopy species throughout much of the northern hardwood forest in the State. A field study was conducted in 2009 in which 50 study plots within 20 small...
Authors
Timothy J. Sullivan, Gregory B. Lawrence, Scott W. Bailey, Todd C. McDonnell, G.T. McPherson

Estimating abundance of the Southern Hudson Bay polar bear subpopulation using aerial surveys, 2011 and 2012 Estimating abundance of the Southern Hudson Bay polar bear subpopulation using aerial surveys, 2011 and 2012

The Southern Hudson Bay (SH) polar bear subpopulation occurs at the southern extent of the species’ range. Although capture-recapture studies indicate that abundance remained stable between 1986 and 2005, declines in body condition and survival were documented during the period, possibly foreshadowing a future decrease in abundance. To obtain a current estimate of abundance, we conducted...
Authors
Martyn E. Obbard, Kevin R. Middel, Seth P. Stapleton, Isabelle Thibault, Vincent Brodeur, Charles Jutras

Evaluation of National Atmospheric Deposition Program measurements for co-located Sites CO89 and CO98 at Rocky Mountain National Park, 2012 Evaluation of National Atmospheric Deposition Program measurements for co-located Sites CO89 and CO98 at Rocky Mountain National Park, 2012

Atmospheric wet-deposition monitoring in Rocky Mountain National Park included precipitation depth and aqueous chemical measurements at co-located National Atmospheric Deposition Program (NADP) sites CO89 and CO98 (Loch Vale) during 2012. The co-located sites are separated by approximately 6.5 meters horizontally and 0.5 meters in altitude, which meets NADP siting criteria. Median weekly...
Authors

Galveston Bay: Chapter D in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010 Galveston Bay: Chapter D in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

The Galveston Bay estuary is located on the upper Texas Gulf coast (Lester and Gonzalez, 2002). It is composed of four major sub-bays - Galveston, Trinity, East, and West Bays. It is Texas’ largest estuary on the Gulf Coast with a total area of 155,399 hectares (384,000 acres) and 1,885 km (1,171 miles) of shoreline (Burgan and Engle, 2006). The volume of the bay has increased over the...
Authors
Lawrence R. Handley, Kathryn A. Spear, Eleonor Taylor, Cindy A. Thatcher

Geohydrologic and water-quality characterization of a fractured-bedrock test hole in an area of Marcellus shale gas development, Bradford County, Pennsylvania Geohydrologic and water-quality characterization of a fractured-bedrock test hole in an area of Marcellus shale gas development, Bradford County, Pennsylvania

Open-File Miscellaneous Investigation 13–01.1 presents the results of geohydrologic investigations on a 1,664-foot-deep core hole drilled in the Bradford County part of the Gleason 7.5-minute quadrangle in north-central Pennsylvania. In the text, the authors discuss their methods of investigation, summarize physical and analytical results, and place those results in context. Four...
Authors
Dennis W. Risser, John H. Williams, Kristen L. Hand, Rose-Anna Behr, Antonette K. Markowski

Geologic assessment of undiscovered oil and gas resources: Oligocene Frio and Anahuac Formations, United States Gulf of Mexico coastal plain and State waters Geologic assessment of undiscovered oil and gas resources: Oligocene Frio and Anahuac Formations, United States Gulf of Mexico coastal plain and State waters

The Oligocene Frio and Anahuac Formations were assessed as part of the 2007 U.S. Geological Survey (USGS) assessment of Tertiary strata of the U.S. Gulf of Mexico Basin onshore and State waters. The Frio Formation, which consists of sand-rich fluvio-deltaic systems, has been one of the largest hydrocarbon producers from the Paleogene in the Gulf of Mexico. The Anahuac Formation, an...
Authors
Sharon M. Swanson, Alexander W. Karlsen, Brett J. Valentine

Geologic map of Oldonyo Lengai (Oldoinyo Lengai) Volcano and surroundings, Arusha Region, United Republic of Tanzania Geologic map of Oldonyo Lengai (Oldoinyo Lengai) Volcano and surroundings, Arusha Region, United Republic of Tanzania

The geology of Oldonyo Lengai volcano and the southernmost Lake Natron basin, Tanzania, is presented on this geologic map at scale 1:50,000. The map sheet can be downloaded in pdf format for online viewing or ready to print (48 inches by 36 inches). A 65-page explanatory pamphlet describes the geologic history of the area. Its goal is to place the new findings into the framework of...
Authors
David R. Sherrod, Masota M. Magigita, Shimba Kwelwa
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