Erosion and Sediment Control Stormwater Calculation and Process Review – Eastern U.S.

A large linear highway construction project was experiencing overflow events from temporary construction stormwater basins. Sediment from these basins was entering adjacent waterways causing concern by the Contractor. Since the project was in the initial stages of construction and additional basins were to be constructed, the client was concerned that the basins were undersized and desired review of the calculations and processes used to size the basins.

STONE reviewed the calculations and methodology completed by others for the construction sediment basin sizing, independently performed the same calculations, reviewed processes and applicability of equations and referenced used, evaluated the validity of the argument that the basins were undersized, and provided a detailed report.

The project had an expedited timeframe of three weeks, which included review of the state’s design manuals, project Erosion & Sediment Control Plans, project construction plan sets, rainfall data, time of concentration parameters, soil types, drainage areas, and calculation sheets. STONE reviewed hundreds of pages of plans, numerous sources of regulatory guidance, and assessed the validity of equations and parameters used within the fast-track time-frame.