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Stormwater Pollution Prevention Plan <br /> If encountered, BMPs to be used for treatment of potentially contaminated dewatering water <br /> include: <br /> • Construction Stormwater Filtration (BMP C251). Not anticipated at this time. <br /> • Construction Stormwater Chemical Treatment(BMP C250). Not anticipated at <br /> this time and implemented only with prior written approval from Ecology. <br /> Alternate dewatering control BMPs are included in Appendix C as a quick reference tool for the <br /> onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate <br /> during construction to satisfy the requirements set forth in the General NPDES Permit(Appendix <br /> D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the <br /> NPDES Construction Stormwater permit(as provided in Appendix D),the Certified Erosion and <br /> Sediment Control Lead will promptly initiate the implementation of one or more of the alternative <br /> BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. <br /> 3.1.11 Element#11 —Maintain BMPs <br /> All temporary and permanent erosion and sediment control BMPs shall be maintained and <br /> repaired as needed to assure continued performance of their intended function. Maintenance and <br /> repair shall be conducted in accordance with each particular BMP's specifications. Visual <br /> monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours <br /> of any stormwater or non-stormwater discharge from the site. If the site becomes inactive, and is <br /> temporarily stabilized, the inspection frequency will be reduced to once every month. <br /> All temporary erosion and sediment control BMPs shall be removed within 30 days after the <br /> final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped <br /> sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs <br /> or vegetation shall be permanently stabilized. <br /> 3.1.12 Element#12—Manage the Project <br /> Erosion and sediment control BMPs for this project have been designed based on the <br /> following principles: <br /> • Design the project to fit the existing topography, soils, and drainage patterns. <br /> • Emphasize erosion control rather than sediment control. <br /> • Minimize the extent and duration of the area exposed. <br /> • Keep runoff velocities low. <br /> • Retain sediment on site. <br /> 12 <br />