Post-Construction Best Management Practices
Post-construction best management practices (PCBMPs) encompass the design, construction and maintenance practices for stormwater facilities that minimize the impact of stormwater runoff, prevent erosion and capture pollutants. Much of the flooding, stream erosion and poor water quality in urban areas is a direct result of impervious surfaces. The more houses, driveways, parking lots and roads there are in a concentrated area, the worse these problems can be. Aside from reducing neighborhood flooding and drainage problems, these practices also improve water quality in ponds, wetlands and streams.
PCBMPs are required to treat the stormwater runoff for pollutants of concern and reduce runoff volume for developments with a net new impervious area of 2,500 square feet or more. Details and exceptions to this requirement are in Article VIII of the Ordinance.
PCBMPs shall provide volume control and pollutant control using infiltration of 1.25 inches for all new impervious surfaces. If providing a PCBMP is found to be impractical, then a fee-in-lieu option may be considered.
If it is not practical to install a PCBMP, the applicant should submit documentation and/or a narrative describing the hardship. If the Stormwater Director finds that installing a PCBMP is impractical, the applicant may participate in a fee-in-lieu program. The fee–in-lieu of constructing a PCBMP is currently $500 per 1,000 square feet of new impervious area. Fees collected are used to design, construct and maintain water quality or runoff volume reduction improvements in the same watershed as collected.
Maintenance of PCBMPs is critical. Some PCBMPs don’t require as much short term maintenance as others, but all PCBMPs will need maintenance at some point. It is important to learn what is needed to maintain your PCBMP before you decide which one to use. Applicants should submit a long term maintenance plan and be aware of what will be needed.