Publications

The Gunnison Basin Selenium Management Program implemented a water-quality monitoring network in 2011 to measure concentrations of selenium in the lower Gunnison River Basin in Colorado. Selenium is a trace element that bioaccumulates in aquatic food chains. Selenium is essential for life, but elevated amounts can cause reproductive failure, deformities, and other harmful effects. The primary goal

Streamflow estimates for floods with an annual exceedance probability of 0.001 or lower are needed to accurately portray risks to critical infrastructure, such as nuclear powerplants and large dams. However, extrapolating flood-frequency curves developed from at-site systematic streamflow records to very low annual exceedance probabilities (less than 0.001) results in large uncertainties in the st

Flood-frequency (hereinafter frequency) estimates provide information used to design, operate, and maintain hydraulic structures such as bridges and dams. Failures of these structures could cause catastrophic loss of property, life, or both. In addition to frequency estimates that use annual peak streamflow, frequency estimates of flood durations are required to safely and effectively operate the

Aquifer flow systems near seawater interfaces can be complicated by density-driven flows and the formation of stagnation zones, which inevitably introduces uncertainty into groundwater age-dating. While age-dating has proved effective to understand the seawater intrusion and aquifer salinization process in coastal aquifers, further efforts are needed to propagate model and data uncertainty to the

OverviewContinuous water-quality monitoring data and chemical analysis of surface-water and groundwater samples collected during 2017–19 in the recharge zone of the Edwards aquifer were used to develop a better understanding of the surface-water/groundwater connection in and around Bexar County in south-central Texas. This fact sheet is provided to inform water-resource managers, city planners, th

Ongoing urbanization on the Edwards aquifer recharge zone in the greater San Antonio area raises concern about the potential adverse effects on the public water supply from development. To address this concern, the U.S. Geological Survey, in cooperation with the City of San Antonio, studied patterns of temporal and spatial changes in water quality at selected surface-water and groundwater sites in

Long Island, New York, has a mix of urban/suburban to agricultural/horticultural land use and nearly 3 million residents that rely on a sole-source aquifer for drinking water. The analysis of shallow groundwater (<40 m below land surface) collected from 54 monitoring wells across Long Island detected 53 pesticides or pesticide degradates. Maximum concentrations for individual pesticides or pestici

A step increase in annual precipitation over the eastern U.S. in the early 1970’s commenced five decades of invigorated hydroclimate, with ongoing impacts on streamflow and water resources. Despite its far-reaching impacts, the dynamical origin of this change is unknown. Here, analyses of a century of atmospheric and oceanic data trace the dynamics to changes in the Indian Ocean. Spring and fall p

Preferential flow, a major influence in unsaturated soil and rock almost everywhere, occurs by multiple phenomenologically distinct hydraulic processes. For the mode known as funneled flow, concentrated in particularly conductive portions of the medium, the surface-tension/viscous-flow processes of traditional unsaturated flow theory predominate. Fingered flow, through conductive paths of higher w

A step increase in annual precipitation over the eastern United States in the early 1970s commenced five decades of invigorated hydroclimate, with ongoing impacts on streamflow and water resources. Despite its far-reaching impacts, the dynamical origin of this change is unknown. Here analyses of a century of atmospheric and oceanic data trace the dynamics to changes in the Indian Ocean. Increases

Municipal and domestic water users in Douglas County, Colorado, rely on groundwater from the bedrock aquifers in the Denver Basin aquifer system as part of their water supply. The four principal Denver Basin bedrock aquifers are, from shallowest to deepest, the Dawson aquifer (divided administratively into “upper” and “lower” Dawson aquifers in Douglas County), the Denver aquifer, the Arapahoe aqu

The greater Port Susan area of Central Puget Sound, Washington, is home to some of the Stillaguamish Tribe’s fishing, hunting, and gathering areas since time immemorial. It is also a popular sport and commercial fishing area for the public. Large shellfish beds lie in the Port Susan and Stillaguamish estuary and several Pacific salmon species return to the Stillaguamish River and Tulalip fishery e