Publications

Analysis of nearly 60,000 reported values of static water level (SWL, as depth below land surface) in bedrock wells in New Hampshire, aggregated on a yearly basis, showed an apparent deepening of SWL of about 13 ft (4 m) over the period 1984–2007. Water-level data were one-time measurements at each well and were analyzed, in part, to determine if they were suitable for analysis of trends...

Base flow in the upper San Pedro River at the gaging station (USGS station 09471550) near Tombstone, Arizona, is an important factor in the long-term sustainability of the river's riparian ecosystem. Most base flow occurs during the non-summer months (typically, from November to May), because evapotranspiration (ET) is greater than groundwater discharge to the riparian zone during the...

Rivers are conduits for water and sediment supplied from upstream sources. The sizes of the sediments that a river bed consists of typically decrease in a downstream direction because of natural sorting. However, other factors can affect the caliber of bed sediment including changes in upstream water-resource development, land use, and climate that alter the watershed yield of water or...

The freshwater zone of the San Antonio segment of the Edwards aquifer in south-central Texas (hereinafter, the Edwards aquifer) is bounded to the south and southeast by a zone of transition from freshwater to saline water (hereinafter, the transition zone). The boundary between the two zones is the freshwater/saline-water interface (hereinafter, the interface), defined as the 1,000...

No abstract available.

Invertebrates have long been used as resident sentinels for assessing ecosystem health and productivity. The shore crabs, Hemigrapsus oregonensis and Pachygrapsus crassipes, are abundant in estuaries and beaches throughout northern California, USA and have been used as indicators of habitat conditions in several salt marshes. The overall objectives of the present study were to conduct a...

Changes in the water quality of stream ecosystems in an urban area may manifest in conspicuous ways, such as in murky or smelly streamwater, or in less conspicuous ways, such as fewer native or pollution-sensitive organisms. In 2004, and again in 2007, the U.S. Geological Survey sampled stream organisms—algae, invertebrates, and fish—in 14 Milwaukee area streams to assess water quality...

Beaver Lake is a large, deep-storage reservoir used as a drinking-water supply and considered a primary watershed of concern in the State of Arkansas. As such, information is needed to assess water quality, especially nutrient enrichment, nutrient-algal relations, turbidity, and sediment issues within the reservoir system. Water-quality samples were collected at three main inflows to...

Upper Klamath Lake is a large (230 square kilometers), shallow (mean depth 2.8 meters at full pool) lake in southern Oregon. Lake circulation patterns are driven largely by wind, and the resulting currents affect the water quality and ecology of the lake. To support hydrodynamic modeling of the lake and statistical investigations of the relation between wind and lake water-quality...

Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research...

The groundwater resources of about 400 square miles of the East Mountain area of Bernalillo, Sandoval, Santa Fe, and Torrance Counties in central New Mexico were evaluated by using groundwater levels and water-quality analyses, and updated geologic mapping. Substantial development in the study area (population increased by 11,000, or 50 percent, from 1990 through 2000) has raised...

The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers-Fort Worth District, City of Corpus Christi, Guadalupe-Blanco River Authority, San Antonio River Authority, and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program ? FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations...