Notes
Exhibit 240 (AR 018981–018983), letter dated September 25, 2000 from Bill Rozeboom to Gordon White, Program Director, Shorelands and Environmental Assistance Program, Washington State Department of Ecology. Second installment of preliminary review comments on the August 2000 Stormwater Management Plan (SMP) for the Seattle-Tacoma International Airport Master Plan Update third runway improvements. Focuses on inadequate assessment of project impacts to stream base flows and seepage flows to wetlands, specifically Miller Creek subbasins SDW1A and SDW1B. Critiques Port of Seattle’s failure to commit to base flow mitigation from the third runway embankment, inconsistencies between SMP Appendix F and HSPF model calibrated parameters (Table A-4), and misrepresentation of the SeaTac Runway Fill Hydrologic Studies Report (Ecology, 2000). Documents that HSPF re-analysis shows groundwater plus interflow at 44% of average annual rainfall versus the 63.6% presented in Appendix F, and that groundwater inputs to Miller Creek are predicted to reduce by 0.10 cfs in July and 0.09 cfs in August from two subbasins alone — approximately twice the SMP’s reported total reductions. References Port March 10, 2000 response to 401/404 comments, Elizabeth Leavitt September 5, 2000 Technical Memorandum, and September 2000 King County review of the SMP. Filed in PCHB third-runway-eis administrative record.