Oregon Water Science Center
Johnson Creek Basin Hydrologic Monitoring PROJECT BACKGROUNDThis is a continuation of a cooperative study between the U.S. Geological Survey (USGS) and municipalities in the Johnson Creek basin. The project was started in 1998 in cooperation with the City of Portland Bureau of Environmental Services, and was expanded in subsequent years to include Clackamas and Multnomah Counties and the cities of Gresham and Milwaukie. This multi-year data collection project will continue to respond to the needs for hydrologic data and analyses, providing answers regarding surface-water, water quality, and ground-water in the basin.Flooding resulting from direct surface runoff and increased ground-water discharge is a potential problem in residential, commercial, and public areas. Commercial and residential development in the basin has likely affected both the high-flow and low- flow hydrologic conditions in the basin. Johnson Creek is one of the region's last free- flowing urban streams and has received Federal listing for native fish. Water-quality standards will be established by the Oregon Department of Environmental Quality over the next several years, and will result in Total Maximum Daily Load allocations for temperature, bacteria, and pesticides. The effects of ongoing changes in land use in the basin on magnitude and duration of high- and low-flow events, as well as water quality require further data collection and study in the future.
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