Volume 2: Draft Gorst Planned Action Environmental Impact Statement

GORST PLANNED ACTION EIS | AFFECTED ENVIRONMENT, SIGNIFICANT IMPACTS, AND MITIGATION MEASURESwould include low and medium density residential areas, which would retain some impervious surface for yardsassociated with dwellings. Additionally, small areas of open space and recreation would be maintained. Therefore,the total loss of soil would be less than the full 70 acres. Creation of new impervious surface could contribute toincreased erosion of soils.Under this alternative, the area that is currently used for mineral resource extraction would be developed intoMedium Density Residential with a mix of housing types. This area includes a large moderate geologic hazard area,as well as large coverage of soils with severe limitations for building and street development. Therefore,construction activities in this area could require substantial mitigation, including project design to minimizeimpacts to soils and geologic resources.Under this alternative, existing regulations and plans to minimize soil erosion, impacts to steep or unstable slopes,and soil contamination would continue to apply, but may be revised in the future based on the recommendationsin the Gorst Stormwater Management Plan, Gorst Subarea Plan, and Gorst Creek Watershed Characterization &Framework Plan, which would be implemented under this alternative. Within the UGA, efforts to minimizeimpervious surface in developed/redeveloped areas would likely result in an overall reduction in effectiveimpervious surface. On a watershed scale, planned improvements to stormwater facilities, stream restoration, andprotection of key recharge/discharge/storage areas, if implemented, would help to minimize the impacts of newdevelopment and associated erosion, and would likely result in a reduction in flooding and export of soils from thewatershed.Alternative 3The area of developable land identified for Alternative 3 is approximately 69 acres, roughly the same as underAlternative 2, but greater than under Alternative 1. In addition to these developable parcel acres, some land wouldbe modified in existing or future rights of way or on lands for public purposes. This alternative includes the sameamount of open space as Alternative 2, as well as low intensity waterfront, which reduces impervious surfaces andpromotes shoreline reclamation and open space. Therefore some soil functions would be retained within thedevelopable land, much like under Alternative 2.Under this alternative, the area that is currently used for mineral resource extraction would be developed intoNeighborhood Mixed Use. As under Alternative 2, the geologic hazard area and soils with limitations on buildingand street development would provide challenges to planned development in this area. Construction activitiescould require substantial mitigation, including project design to minimize impacts to soils and geologic resources.Under this alternative, the Gorst Stormwater Management Plan, Gorst Subarea Plan, and Gorst Creek WatershedCharacterization & Framework Plan would be implemented, as under Alternative 2. Existing regulations and plansto minimize soil erosion, impacts to steep or unstable slopes, and soil contamination would continue to apply, butmay be revised in the future based on the recommendations in listed plans, which would be implemented underthis alternative. Within the UGA, efforts to minimize impervious surface in developed/redeveloped areas wouldlikely result in an overall reduction in effective impervious surface, particularly along Sinclair Inlet with the LowIntensity Waterfront designation. On a watershed level, successful implementation of the recommendations withinthese plans would help minimize any potential erosion increases associated with new watershed development,and would likely result in a reduction in flooding and export of soils from the watershed.Mitigation MeasuresIncorporated Plan FeaturesNew plans that would be implemented under Alternatives 2 and 3 include features that would serve as mitigationfor potential impacts to soils and geologic resources. Implementing regulations associated with the Gorst SubareaPlan, and Gorst Creek Watershed Characterization & Framework Plan would incorporate the suggestedDraft | June 2013 3-9