Union & West - Walpole, MA

Allen & Major Associates, Inc. provided civil engineering for this 192- unit multi-family development. The building features a retail component with structured parking on the ground floor.  The original site was a parking lot. The runoff from the paved parking surface flowed unmitigated (untreated) to a series of catch basins and manholes, which connect with the municipal system from West Street and outlets into a culverted portion of the Neponset River, under an abutting property’s building.  Significant improvements were made to the stormwater management system (SMS) by incorporating structural and nonstructural Best Management Practices (BMPs) to provide stormwater quality treatment and conveyance.  The SMS includes catch basins, roof drains, drain manholes, underground piping, water quality units (proprietary separators), an underground detention system, and an Operation and Maintenance Plan. All of the stormwater runoff from the paved areas of the site is now treated for water quality prior to discharge to the receiving water.