Notes
Exhibit 235 (AR 018954). Letter dated July 23, 2001 from William A. Rozeboom, P.E., Northwest Hydraulic Consultants Inc., to Gordon White, Program Director, Shorelands and Environmental Assistance Program, Washington State Department of Ecology, on behalf of the Airport Communities Coalition (ACC). Raises concerns about low streamflow analyses conducted by Parametrix (Port of Seattle consultant) for Des Moines Creek, Walker Creek, and Miller Creek in connection with Sea-Tac Airport 401 Certification. Identifies three specific deficiencies: (1) model calibration focused on lower basin gages rather than upper basin gages more relevant to airport impacts; (2) failure to account for post-1994 expansion of the Industrial Wastewater System including lagoon linings and leak reduction; (3) failure to address low-flow impacts of future airport business park development at proposed borrow pit sites in the upper Des Moines Creek Basin. Requests that a final report documenting low streamflow analysis and mitigation proposals be issued and subject to public comment before Ecology relies upon it for its 401 decision. References email documents transmitted July 6, 12, and 13, 2001 by Parametrix to Ecology.