Edgefield Stormwater Channel
Stormwater Channel Repair Project
Portland, Oregon; Summer 2008
After vegetation was cleared to make way for a new golf course hole, it was discovered that a small stormwater channel was eroding badly. This channel had gotten worse after a large subdivision was built on the hillside above. The surface water from the impervious surfaces that was collected in the street drains were discharged directly into this channel causing massive erosion and sediment discharge into the wetlands below. Even the smallest rain events caused water levels to go from a trickle to a torrent.
This stormwater channel had been eroding since the housing development project was first built above it in 1997. It discharges to wetlands, which filter out much of the pollutants and heavy metals, and because the channel was heavily covered with non-native vegetation such as blackberry and reed canary grass, it was not evident how bad the erosion was. When the non-native plants were removed, it was possible to see how seriously the channel had eroded; in some places more than four feet deep, all the way down to bed rock.
The Envirolok Vegetated Bag Wall System was used for both the sides and bottom of the stormwater channel. It was installed and woven together with bag stabilizer geogrid to prevent rushing water from compromising the structure. The use of ¾” minus rock in the foundation bags provided the anchor to hold everything together. Flashy stormwater events have seen zero erosion since the installation, and native woody plants are developing where once had only been invasive weeds.
Site construction supervision was provided by Sunmark Environmental, of Portland OR. Permitting was not required for this installation.
Environmental Reviewnd follow-up
The ability of the Envirolok Vegetated Bag Wall System to withstand flashy storm events solved a persistent and costly erosion control issue. IT is also providing a natural progression of native species that are filtering the stormwater, providing erosion protection and keeping sediment from filling in and destroying a sensitve wetland complex below. Everyone associated with this project is
very pleased with the results.
Edgefield Troutdale OR
2126 NE Halsey St
Troutdale, OR 97060
Sunmark Environmental Services, LLC
18032 NE Airport Way
Portland OR 97230
Contact information provided on request