SEDspread: Sediment-Basin Design Tool for Construction Sites

AbstractSediment runoff rates from construction sites can be substantially higher than those of other land uses. Construction stormwater regulations require detailed stormwater pollution prevention plans to minimize environmental impacts associated with construction activities. Sediment basins are temporary sediment control measures used to detain and treat stormwater runoff on-site prior to discharge. This study developed SEDspread, a user-friendly spreadsheet-based design tool for designers to appropriately size temporary sediment basin parameters. The workbook allows users to input site-specific parameters and constraints to determine basin capacity and configuration, surface skimmer size and dewatering rate, auxiliary spillway design, and baffle configuration. The workbook includes a summary sheet that provides users with schematics of the designed basin, available as a supplement to facilitate effective communication between designers and contractors for constructing and installing the basin. SEDspread includes geospatially derived and referenced data that allow for automated selection of design hydrologic and soil conditions through the input of a project location’s U.S. ZIP code. A hydrologic analysis was performed to relate input hydrologic and soil parameters to 2-year, 24-h design volume sizing factors to contain all design storm runoff. To showcase the capabilities of the developed workbook, a case study was performed to compare the actual designs of two construction site sediment basins to the designs generated through SEDspread. The case study resulted in a volumetric difference factors of 3.0, indicating the basins were severely underdesigned for the local 2-year, 24-h design rainfall.