Publications

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Streamwater discharge and chemistry of two small catchments on Catoctin Mountain in north-central Maryland have been monitored since 1982. Repetitive seasonal cycles in stream-water chemistry have been observed each year, along with seasonal cycles in the volume of stream discharge and in groundwater levels. The hypothesis that the observed streamwater chemical cycles are related to seasonal chang

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic

A particle-tracking analysis was done to estimate capture zones for selected public-supply wells in Salt Lake Valley. Twenty-five- and 50-year capture zones were estimated using a regional, finite-difference, ground-water flow model in conjunction with a particle-tracking program. Three sets of wells currently discharging ground water of adequate quality for public use, but located near areas of g

A three-dimensional, finite-difference, numerical model was developed to simulate ground-water flow in the basin-fill material in Salt Lake Valley, Utah. The model was calibrated to steady-state and transient-state conditions. The steady-state simulation was developed and calibrated using hydrologic data defining average conditions for 1968. The transient-state simulation was developed and calibra

The chemical composition and movement of ground water and hydrologic properties of the basin‑fill material were studied to better under‑ stand the flow system in Salt Lake Valley, Utah. Recharge sources and water‑rock interactions influence the water chemistry in the principal and shallow unconfined aquifers. Chloride concentration in water from some wells has increased from the 1950’s and 1960’s

A seepage study was done during 1988 on selected reaches of the Sevier River in Utah above Sevier Bridge Reservoir, the East Fork Sevier River in Black Canyon and Kingston Canyon, Long-East Bench and McEwen Canals in the upper Sevier River basin, and the San Pitch River in Sanpete Valley to determine gain or loss of flow from seepage. A net gain occurred in all of the reaches except Kingston Canyo

The ground-water resources of southern Utah and Goshen Valleys were assessed from 1988 to 1993 to determine the effects that additional ground-water withdrawals would have on water levels, surface water, and water quality. Recharge, movement, and discharge of ground-water were emphasized. The main ground-water system in southern Utah and Goshen Valleys is in the unconsolidated basin-fill deposits.

Ground-water recharge to basin-fill aquifers from unconsumed irrigation water in the western United States is being reduced as irrigators convert to more efficient irrigation systems. In some areas, these changes in irrigation methods may be contributing to ground-water-level declines and reducing the quantity of water available to downgradient users. The components of the water budget were measur

A study was done during 1994 on selected reaches of the Virgin River from Ash Creek to Harrisburg Dome in the central Virgin River area, Washington County, Utah, to determine gain or loss of flow in the river from seepage. There was a net gain of 10.7 cubic feet per second in the selected 14-mile section of the Virgin River near Hurricane, Utah. The two upstream reaches of this section of the rive

The hydrologic system in the central Sevier Valley, and more specifically the Sevier-Sigurd basin, is a complex system in which surface- and ground-water systems are interrelated. Seepage from an extensive irrigation system is the primary source of recharge to the basin-fill aquifer in the Sevier-Sigurd basin.Water-quality data indicate that inflow from streams and subsurface inflow that intersect

Populations of native and introduced aquatic organisms in the San  Francisco Bay/Sacramento-San Joaquin Delta Estuary ("Bay/Delta") have undergone significant declines over the past two decades. Decreased river inflow due to drought and increased freshwater diversion have contributed to the decline of at least some populations. Effective management of the estuary's biological resources requires a