Derry Dell Sanitary Sewer
Derry Dell Sanitary Sewer, Tigard, Oregon. Like many urban streams, Derry Dell Creek suffered from increasing runoff that incised the channel and eroded the banks so severely that an important sanitary sewer main was at risk and adjacent landowners were rapidly losing property. The project restored and enhanced riparian and wetland area at the confluence of Derry Dell and Fanno Creeks, realigning and restoring 1,120 feet of degraded, channelized, and incised stream channel. Additionally, the project enhanced 0.62 acres of wetland and floodplain, creating an additional 56,000 cubic feet of extra floodplain storage. Some 5.1 acres of the site were revegetated with native plant species, and wildlife habitats were created with the installation of over 90 pieces of large wood in the creek channel and floodplain.