USGS Washington Water Science Center
|U.S. Department of the Interior
U.S. Geological Survey
Release: August 17, 2010
[Editors: More about the USGS study is at http://wa.water.usgs.gov/projects/clovercreek/ .]
TACOMA, Wash.--Scientists have sorted out and mapped the shallow aquifers in the Chambers-Clover Creek watershed for the first time. These maps will yield a more accurate picture of how streams and groundwater interact, according to a report published by the U.S. Geological Survey. The report was produced in cooperation with the Pierce Conservation District, local public water suppliers, Pierce County Surface Water Management Division, and the Washington State Department of Ecology.
The USGS report is the second in a series of three reports that will culminate in a computer model of the Chambers-Clover Creek Watershed groundwater-flow system currently under development by the USGS. The model will be a tool to help guide the management of water resources in the watershed.
The USGS study area covers about 706 square miles in western Pierce County and extends northeast to the Puyallup River, southwest to the Nisqually River, and is bounded on the east by foothills of the Cascade Range and on the west by Puget Sound. Scientists used water level measurements and geologic information from 450 water wells to define the watershed's groundwater-flow system. Streamflow measurements from 44 locations were used to analyze the exchange of water between streams and the groundwater-flow system.
"The groundwater-flow system in this watershed is very complex," said Mark Savoca, USGS hydrologist and lead author of the report. "The different water-bearing units--aquifers--vary in thickness considerably from location to location, so figuring out how groundwater flows throughout the system was a good challenge for our scientists."
USGS scientists found that most of the late summer streamflow in the watershed comes from the local aquifers.
The report, "Hydrogeologic Framework, Groundwater Movement, and Water Budget in the Chambers-Clover Creek Watershed and Vicinity, Pierce County, Washington," by Mark E. Savoca, Wendy B. Welch, Kenneth H. Johnson, R.C. Lane, U.S. Geological Survey; Burt G. Clothier, Robinson & Noble Inc.; and Elisabeth T. Fasser, U.S. Geological Survey, is published as U.S. Geological Survey Scientific Investigations Report 2010-5055 and is available on the Web at http://pubs.usgs.gov/sir/2010/5055 .