Post Construction includes regulating earth disturbance, stream bank, and streambed protection, inspecting and maintaining Best Management Practices (BMP), and installation of acceptable BMP for post-construction stormwater management such as permeable paving, grass swale, bioretention, riparian buffers, wet ponds, etc.
For a detailed description of post-construction responsibilities to mitigate stormwater run-off read the Township's ordinance regarding "Responsibilities for operations and maintenance of BMPs".
Several public education brochures from Chester County pertaining to post-construction responsibilities: Note, that the link opens a separate window.