Environmental Assessment Emergency Streambank Protection, North Raccoon River, Iowa State Highway 7 Bridge in Buena Vista County, Iowa

摘要

The purpose of this study was to assess various measures to provide streambank protection along the left descending bank of the North Raccoon River to curtail erosion which is endangering the east approach roadway, abutment wingwall, and deck of the Iowa State Highway 7 bridge in Buena Vista County, Iowa. Riprap Protection, Concrete-Filled Mattress, and No action were considered as alternatives to control the erosion at the study site. Of these alternatives, Riprap Protection was chosen as the selected plan because it was considered to exhibit the best combination of cost effectiveness and reliability in conjunction with minimizing environmental disruption. Riprap Protection is the National Economic Development (NED) plan, i.e., the plan that maximizes net economic benefits. (SDW)