Publications

The Amargosa River is an approximately 300-kilometer long regional drainage connecting the northern highlands on the Nevada Test Site in Nye County, Nev., to the floor of Death Valley in Inyo County, Calif. Streamflow analysis indicates that the Amargosa Desert portion of the river is dry more than 98 percent of the time. Infiltration losses during ephemeral flows of the Amargosa River...

Estimation of representative hydrographs from design storms, which are known as design hydrographs, provides for cost-effective, riskmitigated design of drainage structures such as bridges, culverts, roadways, and other infrastructure. During 2001?07, the U.S. Geological Survey (USGS), in cooperation with the Texas Department of Transportation, investigated runoff hydrographs, design...

INTRODUCTION Declines in the distribution, abundance, and diversity of freshwater-mussel species (family Unionidae1) have been reported worldwide (Bogan, 1993; Strayer and Jirka, 1997). The principal causes of the observed declines are difficult to confirm, however, because only a few of the many factors that affect mussel-species populations have been identified (Strayer and Ralley...

A study was conducted by the U.S. Geological Survey in cooperation with the Missouri Department of Conservation to estimate the effects of existing and proposed impoundments, land-cover changes, and reported water uses on streamflows in the 5,410-square mile upper Osage River Basin. The hydrologic model Hydrologic Simulation Program-FORTRAN (HSPF) was calibrated and validated to current...

This report documents the development and application of a box model to simulate water level, salinity, and temperature of the Alviso Salt Pond Complex in South San Francisco Bay. These ponds were purchased for restoration in 2003 and currently are managed by the U.S. Fish and Wildlife Service to maintain existing wildlife habitat and prevent a build up of salt during the development of...

Mercury contamination in the environment is a global concern, especially in areas with abundant wetlands, such as south Florida. As the causal factors of this concern improve, scientists find that many factors that do not necessarily affect mercury concentrations, such as flooding and drying cycles, or changes to carbon and sulfate loading, can profoundly affect net mercury toxicity...

The high demand for water, the recent multiyear drought (1999-2007), and projections of global warming have raised questions about the long-term sustainability of water supply in the southwestern United States. In this study, the potential effects of specific levels of atmospheric warming on water-year streamflow in the Colorado River basin are evaluated using a water-balance model, and...

Current-use pesticides (CUPs) and banned organochlorine compounds (OCCs) were measured in precipitation (snowpack and rain) and lake sediments from two national parks in the Western United States to determine their occurrence and distribution in high-elevation environments. CUPs frequently detected in snow were endosulfan, dacthal, and chlorothalonil in concentrations ranging from 0.07...

We use selected monitoring data to illustrate how localized water diversions from seasonal barriers, gate operations, and export pumps alter water quality across the Sacramento-San Joaquin Delta (California). Dynamics of water-quality variability are complex because the Delta is a mixing zone of water from the Sacramento and San Joaquin Rivers, agricultural return water, and the San...

Climate over the watershed of the San Francisco Bay Delta estuary system varies on a wide range of space and time scales, and affects downstream estuarine ecosystems. The historical climate has included mild to severe droughts and torrential rains accompanied by flooding, providing important lessons for present-day resource managers. Paleoclimate records spanning the last 10,000 years...

Advanced borehole-geophysical methods were used to assess the geohydrology of fractured crystalline bedrock in 31 of 64 boreholes on the southern part of Manhattan Island, NY in preparation of the construction of a new water tunnel. The study area is located in a highly urbanized part of New York City. The boreholes penetrated gneiss, schist, and other crystalline bedrock that has an...

Regulatory agencies are often charged with the task of setting site-specific numeric water quality standards for impaired streams. This task is particularly difficult for streams draining highly mineralized watersheds with past mining activity. Baseline water quality data obtained prior to mining are often non-existent and application of generic water quality standards developed for...