Volume 2: Draft Gorst Planned Action Environmental Impact Statement

GORST PLANNED ACTION EIS | AFFECTED ENVIRONMENT, SIGNIFICANT IMPACTS, AND MITIGATION MEASURESscrutiny of permits in floodplains and due to the listing of fish species, the developability of the Gorst Creek floodplain area for intensive mixed uses is expected to be challenging.The Low Intensity Waterfront and Open Space/Recreation areas along Sinclair Inlet would accommodate newwater quality treatment, reduce impervious surface areas, and provide an adequate buffer to the shoreline. TheNeighborhood Mixed Use area on the bluffs currently undeveloped but used as mining resources/borrow materialwould impact surface water runoff and alter natural hydrology. However, similar to Alternative 2, new designs anddevelopment would address potential for flooding, potential need for flow control, and treatment, minimizingimpact on hydrology and water quality.Also similar to Alternative 2, Alternative 3 would establish a zero stormwater discharge policy to both streams inthe UGA and the estuary; if implemented this would require 100 percent infiltration or detention. The SUSTAINmodel would be used to optimize and prioritize protection zones.Overall, Alternative 3 would have a minor effect on water resources from both short-term construction relatedimpacts that may involve in-water work and long-term redevelopment of high density commercial areas withmixed use developments. The long-term effects of replacing the existing high density commercial developmentswith a low intensity waterfront along the shoreline and implementation of the adopted WatershedCharacterization & Framework Plan would have a beneficial effect on water resources.Mitigation MeasuresSpecific mitigation measures for potential impacts on water resources would be determined during subsequentproject-specific environmental review and permitting in the watershed and application of the Planned Actionordinance and permitting in the Gorst UGA. Mitigation includes incorporated plan features, applicable regulationsand commitments, and other potential measures.Incorporated Plan FeaturesFeatures of the Watershed Characterization & Framework Plan and Gorst Subarea Plan that serve as mitigation forpotential impacts on water resources include the following concepts found in Guiding Principles and Goals andPolicies:• Identify and protect critical areas such as floodplains along Gorst Creek.• Prioritize areas for restoration that would improve water quality.• Protect and enhance water quality/quantity.• Promote shoreline reclamation.Additionally, capital facility improvements have been recommended to address runoff from impervious surfacesand flood-prone areas.Applicable Regulations and CommitmentsSurface water quality standards are implemented through the CWA Section 401 certifications, water qualitymodifications, and compliance with the standards in Chapter 90.48 RCW and WAC 173-201A. Applications forwater quality related permits include the Joint Aquatic Resources Permit Application (JARPA) process, and theNPDES permits. Applicable regulations and commitments may include the following:• FederalooClean Water ActCoastal Zone Management ActDraft | June 2013 3-23