Evaluation of Inlet Protection Practices (IPPs) Using Large-Scale Testing Techniques

Abstract

Most roadway construction efforts disturb existing vegetation thereby exposing bare soil to environmental variables that cause erosion. Soil eroded during storm events is conveyed by stormwater runoff and may become deposited in receiving waterways. Inlet protection practices (IPPs) are temporary erosion and sediment controls commonly used around inlet drainage structures to prevent erosion while retaining sediment on-site. Increased effluent limitation regulation stringency coupled with greater public awareness with regards to surface water pollution have created the need for understanding the performance of commonly used erosion and sediment control practices. This study developed a methodology and testing apparatus for large-scale replicable performance-based testing of standard IPPs at the Auburn University Erosion and Sediment Control Testing Facility. A two-phased testing regime comprised of clean water structural evaluations and sediment-laden performance evaluations was developed. Data collection procedures included pre- and post-test channel surveys, flow through rates, total suspended solids, and turbidity analysis. The performance of drop inlet protection standards developed by the Alabama Department of Transportation (ALDOT), were assessed through the developed methodology. The study evaluated the performance of; aggregate sandbag, silt fence, wattle, and manufactured devices. Structural improvement recommendations were provided to current practices, and testing protocols were established for future product evaluation.