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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 595 records · Page 33Linked to original sources
USGS1998

Monitoring the Water Quality of the Nation's Large Rivers: Columbia River Basin NASQAN Program

In 1995, the U.S. Geological Survey's (USGS) National Stream Quality Accounting Network (NASQAN) Program began monitoring the water quality of the Columbia River Basin, applying a basinwide approach in order to understand water quality on a regional scale. A primary objective of the Columbia NASQAN Program is to provide an ongoing characterization of the concentrations and mass flux (amount of material or load passing a location per unit time, generally expressed as tons per day) of sediment and chemicals at key locations in the basin. These data can then be used to determine regional source areas for these materials, and to assess the effect of human influences on observed concentrations and constituent loads. NASQAN complements the ongoing USGS National Water Quality Assessment (NAWQA) Program, which is performing a detailed assessment in three subbasins of the Columbia River Basin. NASQAN monitors the larger rivers in the basin, downstream of NAWQA study units.

Fact Sheet↗
USGS1999

Arizona

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Fact Sheet↗
USGS2000

Delta subsidence in California: The sinking heart of the state

The Sacramento-San Joaquin River Delta of California once was a great tidal freshwater marsh blanketed by peat and peaty alluvium. Beginning in the late 1800s, levees were built along the stream channels, and the land thus protected from flooding was drained, cleared, and planted. Although the Delta is now an exceptionally rich agricultural area (over a $500 million crop value in 1993), its unique value is as a source of freshwater for the rest of the State. It is the heart of a massive north-to-south waterdelivery system. Much of this water is pumped southward for use in the San Joaquin Valley and elsewhere in central and southern California. The leveed tracts and islands help to protect water-export facilities in the southern Delta from saltwater intrusion by displacing water and maintaining favorable freshwater gradients. However, ongoing subsidence behind the levees reduces levee stability and, thus, threatens to degrade water quality in the massive north-to-south water-transfer system.

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USGS2003

Municipal stormwater sampling program, metropolitan area, Albuquerque, New Mexico—summary of sampling, 1992–2002

Since 1992, the U.S. Geological Survey (USGS), in cooperation with the City of Albuquerque, the Albuquerque Metropolitan Arroyo and Flood Control Authority (AMAFCA), the New Mexico Highway Department (NMHD), and the University of New Mexico (UNM), has collected stormwater-quality data to meet regulatory requirements for the application phase of the National Pollutant Discharge Elimination System (NPDES) stormwater permit. The phase I permit requirements apply to cities with populations of 100,000 or greater (U.S. Environmental Protection Agency, 1990). This report describes the stormwater sampling program implemented in the City of Albuquerque from 1992 to the present (2002).

Fact Sheet↗
USGS1999

Arkansas

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Fact Sheet↗