Volume 2: Draft Gorst Planned Action Environmental Impact Statement

GORST PLANNED ACTION EIS | AFFECTED ENVIRONMENT, SIGNIFICANT IMPACTS, AND MITIGATION MEASURES• TribaloTribal consultation or approval is required under federal statutes including the CWA Section 401 WaterQuality Certification.• StateooooWater Pollution Control Act (Chapter 90.48 RCW)Shoreline Management Act (Chapter 90.58 RCW)Coastal Zone Management Act CertificationWatershed Planning Law (Chapter 90.82 RCW)o Hydraulic Project Approval (WAC 220-110)oooAquatic Lands Use AuthorizationOn-Site Sewage Facility PermitNPDES Construction Stormwater Permit• LocaloooooCAO PermitShoreline Management PermitFloodplain Development PermitBMCKCCOther Potential Mitigation MeasuresOther potential mitigation measures could include the following:• During construction, future projects will need to comply with all construction-related stormwaterrequirements, including temporary erosion and sediment control, and development and implementation of astormwater pollution and spill prevention plan.• The project-specific design will determine the necessary permanent, long-term water quality treatmentrequirements, necessary for all vehicle-accessible areas and redevelopments. Large areas of landscaping orlawn, unless strict policies on pesticide and fertilizer use are adopted, will also be subject to water qualitytreatment requirements.• No specific water quality treatment method is proposed at this point, but it is likely that treatment wouldconsist of various LID systems to the extent feasible. Additional erosion protection improvements may beneeded at project outfalls because of increased peak runoff rates caused by an increase in impervious surface.• If Gorst Subarea Plan policies and BMPs are implemented with corresponding development regulations therewould be incentives for the removal of existing impervious areas and smaller new impervious footprints.Implementation of these types of incentives and standards could result in beneficial effects on waterresources.• The concept of allowing commercial or mixed uses on smaller impervious footprints could be extended to theGorst Creek corridor and floodplain similar to Low Intensity Waterfront designation, recognizing theconvergence of critical areas and difficulties of development in the floodplain. This would replace portions ofCommercial Corridor in Alternative 2 and Gorst Mixed Use in Alternative 3.Draft | June 2013 3-24