USGS Washington Water Science Center
|U.S. Department of the Interior
U.S. Geological Survey
Release: December 22, 2005
[Note: The report can be viewed on the Web at http://pubs.water.usgs.gov/sir20055255/ .]
Ground water flowing into streams through streambeds is not the primary source of fecal bacteria and nitrates often found in the streams of the lower Nooksack River basin, according to a new report published by the U.S. Geological Survey (USGS), in cooperation with the Nooksack Indian Tribe.
A series of previous studies had consistently found elevated concentrations of fecal bacteria and nitrate in lowland streams of the basin. Because the basin is an area where large quantities of manure are applied to fields above the shallow, highly permeable Sumas aquifer, some scientists theorized that ground water might be the source of the bacteria.
"We sampled ground water at several sites where we thought we’d have the best chance of finding fecal bacteria in the ground water," said Steve Cox, USGS hydrologist and lead author of the report. "We rarely found measurable concentrations of bacteria or nitrates, so it’s reasonable to say that, at these sites, ground water is not the source."
Nitrate concentrations in ground water have been steadily increasing in many parts of the basin over the last 20 years.
The report, "Ground Water/Surface Water Interactions and Quality of Discharging Ground Water in Streams of the Lower Nooksack River Basin, Whatcom County, Washington," by Stephen E. Cox, F. William Simonds, Llyn Doremus, Raegan L. Huffman, and Rose M. Defawe, is published as U.S. Geological Survey Scientific Investigations Report 2005-5225. The report can be viewed on the Web at http://pubs.water.usgs.gov/sir20055255/. Copies can be purchased from the U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225-0286, telephone 303-202-4200.
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