Innovative Streambank Protection in an Urban Setting, Accotink Creek, VA

Abstract : The goal of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to present the planning, design, construction and 10-year performance evaluation of a comprehensive streambank protection project constructed in an urban watershed (Figure 1). This project used a combination of bendway weirs and longitudinal peaked stone toe protection (LPSTP or stone toe) to protect bridge abutments, stabilize an eroding bank line, and initiate floodplain formation. The project features were adjusted to site conditions to minimize environmental impacts. The project is a good example of the use of bendway weirs and stone toe in combination to provide effective, economical, and environmentally sound streambank protection. The project site is located on Accotink Creek in south central Fairfax County, VA, and it provides protection for Panther Bridge, Fort Belvoir. The U.S Army Engineer Research and Development Center s Coastal and Hydraulic Laboratory (ERDC-CHL) was tasked with devising a conceptual design to stabilize erosion to bridge abutments, an eroding bend and a straight reach upstream of a two-lane highway bridge on Accotink Creek. The twolane road is called Farrar Road and is the major thoroughfare to the installation s airport. Planning for the project started in 1996, construction was performed in September 1997, and it has been reviewed periodically (most recently in December 2008). ERDC-CHL provided construction oversight, and taught a stream stabilization/restoration class during the project construction window.