Groundwater Elevation and Temperature in Johnson Creek Basin

Science Center Objects

Water elevation and temperature in groundwater and Johnson Creek at Sycamore, near Portland, OR

Elevation and temperature of groundwater and a stream at a site are useful to understand and quantify the exchange of groundwater and surface water. Elevation information can be used to determine the direction of water flow (flow is from locations of high water elevation to locations of low water elevation). Temperature information can be used to model the direction and quantity of exchange of groundwater and surface water. Collection of groundwater and stream information began on October 1, 2014 at Johnson Creek at Sycamore, a site in Portland, Oregon to understand the exchange of groundwater and surface water in an urban watershed.

Johnson Creek flows 26 miles from agricultural and forested uplands to urban and industrial lowlands of Portland, Oregon. The channel is cut into sediments consisting of silt, sand, and gravel. The drainage area at the Johnson Creek at Sycamore gage (station 14211500) is 26.8 square miles. Upstream of the gage, land use is predominantly residential, forested, and agricultural. The site of the gage and wells is a narrow valley (1,000 feet wide) bounded by low relief hills of basalt to the north and south. Streamflow is flashy with high flows (more than 100 cubic feet per second (cfs)) in the rainy winter and low flows (less than 3 cfs) in the dry, late summer. Groundwater levels are measured in a deep (53 ft) well (station 452840122302201) and a shallow (16 ft) well (station 452840122302202)

xsection for johnson creek
Cross section diagram of coupling of real-time groundwater and streamflow gage at Johnson Creek at Sycamore, near Portland, OR(Public domain.)