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National Water-Quality Assessment Program (NAWQA)
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State assessments of beneficial uses and impaired waters (TMDLs)

Consistent and comparable monitoring information is needed to effectively assess beneficial uses (as required in USEPA 305(b) reporting) and impaired waters (as required in USEPA 303(d) reporting), and to develop Total Maximum Daily Loads (TMDLs). NAWQA information on the occurrence, sources, and transport of contaminants is used by states and tribes to meet these requirements.

Wind River Environmental Quality Commission of the Shoshone and Arapahoe Tribes, Wyoming—USGS assists the tribal Wind River Environmental Quality Commission of the Shoshone and Arapahoe Tribes in sampling large river sites. NAWQA protocols are used for selected water-column and aquatic ecological sampling. The Commission will use this information to compile their 305(b) report and to make management decisions on the surface-water resources.

State of Missouri—The Missouri Department of Natural Resources has incorporated NAWQA stream-quality data into their database for monitoring compliance with 305 (b) water-quality standards. The Department uses the data to describe attainment of beneficial uses, to identify and prioritize problems, to help develop Total Maximum Daily Loads (TMDLs), and to assist in overall natural resource management.

State of New Jersey—The New Jersey Department of Environmental Protection used NAWQA findings in the preparation of their 2000 305(b) report. Specifically, NAWQA information was used to report (1) the long-term nature of nitrate contamination; (2) improvements in stream conditions and fish communities in northern New Jersey due to improvements in waste water treatment; (3) relations between impaired biological communities in urban streams and impervious surfaces; and, (4) use of synthetic chemicals on biological health. NAWQA findings on pesticides and -s will be used by the New Jersey Department of Environmental Protection to prepare their 2002 305(b) report.


An understanding of critical factors controlling sources and transport has proved critical in the accurate establishment of TMDLs in selected stream segments across the nation.

Minneapolis, Minnesota—NAWQA findings for Shingle Creek and other urban streams near the greater Minneapolis metropolitan area brought to light what now appears to be a widespread chloride problem with significant implications regarding TMDL “course-of-actions.” Chemical and biology samples collected by USGS in Shingle and Nine Mile creeks and 13 other major streams in the metropolitan area indicated clear relations between chloride concentrations and impervious surfaces and snowmelt (which is highly suggestive of salt applications for road-deicing). The data, placed in context with other NAWQA samples in urban streams throughout the Nation, showed that both locally and nationwide, chloride concentrations significantly increase with increasing development. Prior to these USGS findings, the Shingle Creek Watershed Management Commission believed that chloride in Shingle Creek was a local, and solely a stockpile, issue. On the basis of USGS chloride results, the Commission now recommends a metropolitanwide approach to assess current practices of road salt use and to explore alternatives to sodium chloride (such as calcium magnesium acetate, which is higher in cost, but has a slower activation rate). The improved assessment of chloride sources led to improved strategies needed to meet Minnesota standards.

Fort Worth, Texas—USGS works with the Texas Natural Resource Conservation Commission and City of Fort Worth to better understand the occurrence, transport, and effects of legacy pollutants, such as DDT and PCBs, in urban streams and lakes in Fort Worth, Texas. The information is used by the State in their TMDL assessments of impaired urban waters. USGS is leading a comprehensive sediment coring and suspended-sediment sampling program, which is designed to determine if, and at what rates, these pollutants enter urban streams and lakes and how long it could take for these pollutants to naturally attenuate to safe levels.

State of North Carolina—An improved understanding of sources and transport has also proved critical for accurate setting of TMDLs in North Carolina. NAWQA findings in the Albemarle-Pamlico Sound, North Carolina highlighted natural sources of elevated phosphorus concentrations, which are needed to fully account for all contributing sources. In addition, USGS works with the North Carolina Water Resources Research Institute to assess and model watersheds within the Neuse River Basin in order to support TMDL decisions.

State of Idaho—The Idaho Department of Environmental Quality used NAWQA results on phosphorus sources and transport to formulate a TMDL for phosphorus in the middle Snake River. NAWQA findings on nitrogen and sediment were also used.

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