St. Louis County, Missouri
Client:
Arbor Valley, LLC
Terra Technologies designed bank stabilization measures necessary to protect a planned residential development from severe stream erosion along the west tributary to Fishpot Creek in St. Louis County, Missouri. A stream geomorphic report and design summary determined that this tributary was experiencing mass wasting and significant lateral instability similar to the main Fishpot Creek channel. This is due to the flashy surface water flows caused by the increased amount of impervious surfaces in the watershed.
The bank stabilization design included shrub plantings in areas of minimal instability and biotechnical gravity retaining walls in locations of severe erosion. These retaining walls extended into the stream channel in order to re-establish the original channel geometry and to allow for a backslope that could tie in to the existing top of bank. The base of the walls consisted of gabion baskets to stabilize the stream toe and the backslopes were geogrid reinforced steepened slopes with high-tensile turf reinforcement mats on the surface to maintain surficial stability. All project areas were then planted with a diverse mixture of native riparian plant species.
Terra Technologies acquired the necessary permits for the project, including approval by the Metropolitan St. Louis Sewer District and St. Louis County as well as Clean Water Act Section 404 & Section 401 authorization for the bank stabilization activities and for the residential development by the U.S. Army Corps of Engineers and the Missouri Department of Natural Resources.
Construction was initiated in late 2008.
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