Publications

This study assesses how rivers, wetlands, island drains and open water habitats within the Sacramento-San Joaquin River Delta affect dissolved organic matter (DOM) content and composition, and disinfection byproduct (DBP) formation. Eleven sites representative of these habitats were sampled on six dates to encompass seasonal variability. Using a suite of qualitative analyses, including...

A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and...

Despite their trophic importance and potential importance as bioindicators of stream condition, benthic algae have not been well studied in California. In particular there are few studies from small streams in the Sierra Nevada. The objective of this study was to determine the standing crop of chlorophyll-a and benthic algal species assemblages present in the small 1st- and 2nd-order...

We have developed a physically based, distributed surface energy balance model to simulate glacier mass balance under meteorological and climatological forcing. Here we apply the model to estimate summer ablation on South Cascade Glacier, Washington, for the 2004 and 2005 mass balance seasons. To arrive at optimal mass balance simulations, we investigate and quantify model uncertainty...

To a casual observer, tropical Pacific islands seem idyllic. Closer scrutiny reveals that their generally small size makes them particularly vulnerable to economic and environmental stresses imposed by rapidly growing populations, increasing economic development, and global climate change. On these islands, freshwater is one of the most precious resources. Ground water is the main source...

This report documents HUFPrint, a computer program that extracts and displays information about model structure and hydraulic properties from the input data for a model built using the Hydrogeologic-Unit Flow (HUF) Package of the U.S. Geological Survey's MODFLOW program for modeling ground-water flow. HUFPrint reads the HUF Package and other MODFLOW input files, processes the data by...

The U.S. Geological Survey (USGS), in cooperation with the Miami Conservancy District, collected and analyzed samples of the aquifer materials and ground water from multiple depths at two sites in northern Preble County, Ohio. The aquifer materials included glacial deposits and Silurian carbonate bedrock. In the study area, elevated arsenic concentrations have been detected in ground...

This report by the U.S. Geological Survey, in cooperation with the San Antonio Water System, describes the results of a statistical analysis of major ion and trace element geochemistry of water at seven wells transecting the freshwater/saline-water interface of the Edwards aquifer in San Antonio, Texas, either over time or in response to variations in hydrologic conditions. The data used...

The quality of water in the Rio Grande is becoming increasingly important as more surface water is proposed for diversion from the river for potable and nonpotable uses. In cooperation with the Albuquerque Bernalillo County Water Utility Authority, the U.S. Geological Survey examined traveltime of the Rio Grande in the Middle Rio Grande Basin to evaluate the potential travel of a...

The U.S. Geological Survey, in cooperation with the Houston-Galveston Area Council and the Texas Commission on Environmental Quality, collected water-quality, stream-habitat, and biological data from five sites on Highland and Marchand Bayous in Galveston County, Texas, during 2006–07. Water-quality data-collection surveys consisted of synoptic 24-hour continuous measurements of water...

The U.S. Geological Survey (USGS), in cooperation with the Maine Department of Marine Resources Bureau of Sea Run Fisheries and Habitat, began a study in 2004 to characterize the quantity, variability, and timing of streamflow in the Dennys River. The study included a synoptic summary of historical streamflow data at a long-term streamflow gage, collecting data from an additional four...

Water Year 2006 (October 1, 2005, to September 30, 2006) was a year of extreme hydrologic drought and the driest year in the recent 2002-2006 drought in Oklahoma. The severity of this recent drought can be evaluated by comparing it with four previous major hydrologic droughts, water years 1929-41, 1952-56, 1961-72, and 1976-81. The U.S. Geological Survey, in cooperation with the Oklahoma...