Hydrophiles Winter 2000 Field Trip Urban Watershed Issues: Johnson Creek and the Columbia Slough March 18, 2000

The Johnson Creek trailhead, with ongoing construction of a bioswale to treat stormwater runoff.

Riparian improvements circa 1930.  The WPA wall on Johnson Creek constructed by the CCC.  A large portion of Johnson Creek is rock lined, forming a perfect trapezoidal channel.  "De-hardening" of the channel to restore natural ecological and hydrological functioning of the system has been discussed, however cultural concerns regarding the historical value of the wall have also been raised.
 

Results of streambank hardening.  The hydraulic jump is caused by a sewer pipe which was buried beneath the Johnson Creek channel, and and now stands above the water surface during low flows as a result of channel incision.  More recent channel stabilization efforts are visible in the foreground.

Two views of the Clearwater Ponds restoration area.  Several homes within the Johnson Creek floodplain at this location were recently purchased by the BES, completely removed and replanted with native vegetation.  Channel overflow and backwater habitat areas were also constructed to provide floodplain storage during high flows and refuge for fish (right photo).  

A regional perspective of the Johnson Creek basin from Hawthorne Ridge.  Continuing land-use alterations in the upland portions of the basin exemplify the need for effective environmental planning in order to protect the riparin zones and assure te efficacy of restoration activities.

The USGS Sycamore gauging station on Johnson Creek, with Karl Lee, USGS Hydrologist.  Equipment pictured in the right photo includes a bubbling pressure transducer, datalogger, and voice synthesized modem to provide discharge information by telephone.

Following the tour of Johnson Creek, we headed to the USGS offices for a discussion on regional groundwater flow in the basin and USGS monitoring activities.