NTM Engineering, Inc. (NTM) was contracted by the Woodmere Art Museum to design Green Stormwater Infrastructure (GSI) for a new parking lot at this museum located in Philadelphia County, Pennsylvania. The project was funded through a Pennsylvania state redevelopment grant and a Pennsylvania Water Department Stormwater Management Incentives Program grant, necessitating extensive design and permitting coordination.
The purpose of the project was to alleviate pervasive flooding and replace the existing parking lot. The new parking lot consists of a combination of porous asphalt and standard asphalt pavement and includes subsurface stormwater infiltration pits. The project also involved the installation of a vegetated bioswale and native meadow plantings for stormwater management. Off-site storm drains and regenerative step-pool water quality system were required to safely pass large flood events. In addition, the project includes a statue designed to reuse stormwater in a fountain.
The design and permitting had to address the requirements of the new (2016) Philadelphia Stormwater guidance and the Wissahickon Act 167 plan, and the project was large enough that PADEP required approval of the NPDES permit. A known impairment of the receiving water necessitated the application of antidegradation techniques for erosion and sediment control BMPs. In addition to stormwater and E&S permit applications, NTM’s permitting efforts included assisting with a zoning variance, building permits, and sewer planning exemption, and obtaining storm drain connection approval.