IMA Fieldwork Collage
Environmental Projects  





Project: Teton River Bank Stabilization- Morey
Location: Teton Valley, ID
Date: 2002
To stabilize 250 feet of eroding bank close to a home on the Teton River using bio-engineering techniques rather than traditional rip-rap.

Wetland sod in combination with erosion control fabric was used to re-construct and stabilize an eroding stream bank on the Teton River. The Teton River is located in southeast Idaho and has an average baseflow of 200 cfs and average peak flow of 1200 cfs. Above and throughout the study area the Teton River is a predominantly ground water fed, free flowing system with a moderate spring run-off. Conditions at the study site pre-construction included an average bank height of 3.5 feet, bank slopes of 2:1 or steeper and dominant bank vegetation consisting of introduced pasture grasses. The existing bank was reconstructed by first excavating the bank down to the base-flow water line to a width of 12 feet. Two layers of erosion control fabric were staked onto the base of the excavated bank and soil was compacted onto the fabric to a depth of 1 foot and a width of 3 feet. The remaining erosion control fabric was then wrapped up onto the compacted soil to build the initial toe of the reconstructed bank. The remaining soil was sloped back to create a bank with a maximum slope of 3:1. Mature wetland sod pre-grown with native sedges and rushes was installed in two 3-foot rows onto the constructed toe and remaining bank to a width of 6 ft. The area behind the wetland sod was seeded with native riparian grasses and forbs. A total of 250 linear feet of eroding bank was reconstructed in 2 days. Two and a half weeks after construction the wetland sod material was fully rooted and could not be displaced by human or livestock disturbance. When last inspected in the summer of 2007, the restored bank is stable and supports deep pools that are holding large trout.