(A) Presumed compliance with SCDHEC water quality standards. All structural stormwater management facilities shall be selected and designed using the appropriate criteria from the most recent version of the City of Easley’s Land Development Regulations and or the SCDHEC BMP Manual. For other structural stormwater controls not included in these manuals, or for which pollutant removal rates have not been provided, the effectiveness and pollutant removal of the structural control must be documented through prior studies, literature reviews, or other means and receive approval from the SWMD before being included in the design of a stormwater management system. Structural best management practices (BMPs) must be designed to remove 80% of the average annual post development total suspended solids (TSS). It is presumed that a BMP complies with this performance goal if it is:
(1) Sized to capture the prescribed water quality volume;
(2) Designed according to the specific performance criteria outlined in the City of Easley’s Land Development Regulations and or the SCDHEC BMP Manual;
(3) Constructed properly; and
(4) Maintained regularly.
(B) Pollutant loading calculation assessment.
(1) For subdivisions of 30 lots or more, any commercial project with a building 10,000 square feet or more, or any project in an area designated by the SWMD as a sensitive/critical area, a pollutant loading calculation shall be conducted to document compliance with water quality standards by calculating pre-development loads, calculating uncontrolled post-development loads and then applying a prescribed pollutant removal efficiency to selected practices to arrive at a net pollutant load delivery. The post-developed load must be equal to or less than the pre-developed load.
(2) The methodology for this calculation shall be in accordance with method provided in Appendix A of Ord. 2008-06, a copy of which is available for public inspection during normal business hours in the office of the City Clerk. (See Appendix A for an example methodology for calculating pollutant load and assessing compliance.)
(Ord. 2008-06, passed 4-14-08) Penalty, see § 52.999