Integrated Methodology of Design for Construction Site Sedimentation Basins

The performance of four sedimentation basins (SBs) at a Pennsylvania Department of Transportation I-99 highway construction site was evaluated based on their particle removal ability. Suspended solids data from the basins indicated poor particle removal, peaks in suspended solid concentration that correlated with rainfall peaks and possibility of sediment resuspension. The current Pennsylvania Department of Environmental Protection basis for basin design is the allocation of 28 m3 (1,000 ft3 ) of sediment storage zone and 140 m3 (5,000 ft3 ) of drainage zone per disturbed acre of the drainage basin. Overflow rate, which is a scientific basis for particle removal, is currently not considered in the design of basins. This paper presents a methodology for developing an integrated design for SBs, applying rainfall probability plots to determine an appropriate basin settling volume. The revised universal soil loss equation is used to identify sediment zone volume, and an overflow rate is determined to design basin surface area. The method presented is a comprehensive procedure for designing SBs with flexibility to choose the extent of particle removal and runoff capture, and to vary construction costs.