Notes
Exhibit 229 (AR 018909–018911), dated November 24, 1999, is a technical comment letter from Northwest Hydraulic Consultants (NHC) — signed by Mr. Rozeboom and Dr. Leytham — submitted to U.S. Army Corps of Engineers Project Manager Jonathan Freedman and Washington State Department of Ecology Environmental Specialist Tom R. Luster, on behalf of the Airport Communities Coalition (ACC). The letter identifies major deficiencies in the Preliminary Comprehensive Stormwater Management Plan (SMP) by Parametrix for the Third Runway Master Plan Update at Sea-Tac Airport. Key findings include: failure to comply with the 1998 King County Surface Water Design Manual (KCSWDM) and Washington State Department of Ecology Stormwater Management Manual; failure to prepare a Master Drainage Plan (MDP) as required for large site drainage review (more than 50 acres of new impervious surface, approximately 200 acres proposed); failure to address KCSWDM Core Requirements 1–3 (discharge at natural location, offsite analysis, flow control); failure to address Ecology Minimum Requirement #5 streambank erosion control; and establishment of target flows potentially too high for Miller Creek, Des Moines Creek, and Walker Creek. The letter also critiques the diversion of 45.7 acres to the Industrial Wastewater System (IWS) and the use of the Miller Creek basin HSPF simulation model.