Assessment and Recommendations for the Operation of Standard Sumps as Best Management Practice for Stormwater Treatment (Volume 1)

Standard sumps are installed in many urban and suburban storm sewer systems. They may qualify as a best management practice (BMP) to pre-treat stormwater runoff by removing suspended sediment from the water. However, no data exist on the effectiveness of sediment removal and maintenance requirements of the sumps. Such data could justify giving pollution prevention credits to transportation departments, municipalities, counties and other local governments for the use of standard sumps. The goals of this study were to (1) evaluate four configurations of a flow-though standard sump for sediment capture and washout; (2) design a simple retrofit for standard sumps to improve sediment capture and decrease washout; (3) develop a performance function estimating the efficiency of standard sumps in removing suspended sediments; (4) develop another function estimating the sediment washout in standard sumps. This volume of the final report (Volume 1) only focuses on the performance of standard sumps. The second volume of the final report will be on the design and performance of the retrofit for improving the sediment capture and lowering the washout rate.