Evaluation of Wheat Straw Wattles for Velocity Reduction in Ditch Check Installations

Abstract

Linear construction typically uses drainage conveyances to convey storm-water runoff away from construction sites to neighboring water bodies. These conveyances may be unstabilized and highly susceptible to erosive shear stresses associated with high-velocity flow. In certain situations, wattle ditch checks are used to help reduce channel erosion caused by high-velocity flow by creating an impoundment. However, with new technology emerging and limited scientific data available on the in-field performance of wattles, the quantification of an installation's effectiveness for improving runoff control is difficult. The effectiveness of various configurations of wattle ditch check installations was investigated at the Auburn University Erosion and Sediment Control Testing Facility to help the Alabama Department of Transportation (DOT) improve the performance of wattle ditch checks. Results indicate that Alabama DOT's current installation practice of staking a wattle only to an unstabilized channel can be improved. The addition of a filter fabric underlay protects the channel bottom from scour at the installation area, and the use of sod staples coupled with a teepee staking pattern secures the wattle in place and increases ground contact, which reduces undercutting. This configuration ultimately minimizes highly erosive supercritical flows and maximizes the subcritical flow length by 99% compared with the base installation.