Evaluating Channelized Flow Sediment Control Practices Using Large-Scale Testing Techniques

Abstract

Ditch checks are used throughout highway construction and are a critical element in the erosion and sediment control plan. The purpose of a ditch check is to reduce flow rates, thereby minimizing channel erosion. Proper installation is required for these devices to perform as intended. Auburn University’s Erosion and Sediment Control Testing Facility (AU-ESCTF) was developed to evaluate ditch check devices used in the Alabama Department of Transportation’s (ALDOT) erosion and sediment control design practices. A channelized flow testing facility was developed with the ASTM D7208-06 standard in mind, along with ALDOT’s design practices and needs taking precedence. Testing procedures have been developed based on ASTM D720806 as well as ALDOT’s needs regarding ditch check performance testing. This paper presents the ditch check testing setup and results of testing runs using 20” wattles. Water depths and flow velocities at eight cross sections were measured and agree well with predicted results from standard hydraulics equations. Changes in flow velocities and energy gradient lines were used to evaluate and assess channel erosion within the ponding and discharge zones of the ditch check. Various installation practices of ditch checks and their performances (e.g., local erosions in the channel and after ditch check) are discussed. Introduction With more stringent effluent guidelines under review by the U.S. EPA and with the vast amount of erosion and sediment control products available, the ALDOT required a means for scientifically evaluating channelized erosion and sediment control practices and devices. ALDOT’s previous evaluation procedure relied upon on-site installations with visual evaluations of practice or product performance. The AU-ESCTF was designed and constructed to fulfill ALDOT’s testing and evaluation requirements. The design of the experimental channels used to test these products and practices was set to mimic the design practices of the ALDOT. The two channelized practices in most need for proper scientific evaluation are the use of ditch checks as an erosion control device to slow and pond runoff, therefore reducing erosive forces; and the use of inlet protection devices and practices as sediment control practices. 372 World Environmental and Water Resources Congress 2012: Crossing Boundaries © ASCE 2012