Laserfiche WebLink
B. General Requirements <br /> I. The SWPPP must include a narrative and drawings. All BMPs must be clearly referenced in <br /> the narrative and marked on the drawings.The SWPPP narrative must include <br /> documentation to explain and justify the pollution prevention decisions made for the <br /> project. Documentation must include: <br /> a. Information about existing site conditions(topography, drainage, soils, vegetation, etc.). <br /> b. Potential erosion problem areas. <br /> c. The 13 elements of a SWPPP in Special Condition S9.D.1-13, including BMPs <br /> used to address each element. <br /> d. Construction phasing/sequence and general BMP implementation schedule. <br /> e. The actions to be taken if BMP performance goals are not achieved—for example, <br /> a contingency plan for additional treatment and/or storage of stormwater that <br /> would violate the water quality standards if discharged. <br /> f. Engineering calculations for ponds, treatment systems, and any other designed <br /> structures.When a treatment system requires engineering calculations, these <br /> calculations must be included in the SWPPP. Engineering calculations do not need to <br /> be included in the SWPPP for treatment systems that do not require such calculations. <br /> 2. The Permittee must modify the SWPPP if, during inspections or investigations conducted <br /> by the owner/operator,or the applicable local or state regulatory authority, it is <br /> determined that the SWPPP is, or would be, ineffective in eliminating or significantly <br /> minimizing pollutants in stormwater discharges from the site.The Permittee must then: <br /> a. Review the SWPPP for compliance with Special Condition S9 and make appropriate <br /> revisions within 7 days of the inspection or investigation. <br /> b. Immediately begin the process to fully implement and maintain appropriate source <br /> control and/or treatment BMPs as soon as possible, addressing the problems no later <br /> than 10 days from the inspection or investigation. If installation of necessary treatment <br /> BMPs is not feasible within 10 days, Ecology may approve additional time when an <br /> extension is requested by a Permittee within the initial 10-day response period. <br /> c. Document BMP implementation and maintenance in the site log book. <br /> The Permittee must modify the SWPPP whenever there is a change in design, <br /> construction,operation,or maintenance at the construction site that has, or could have, <br /> a significant effect on the discharge of pollutants to waters of the State. <br /> C. Stormwater Best Management Practices (BMPs) <br /> BMPs must be consistent with: <br /> 1. Stormwater Management Manual for Western Washington (most current approved <br /> edition at the time this permit was issued), for sites west of the crest of the Cascade <br /> Mountains; or <br /> Construction Stormwater General Permit Page 24 <br />