Notes
Internal email from Tom Luster (Washington State Department of Ecology) to Raymond Hellwig, Kevin Fitzpatrick, Erik Stockdale, and Paula Ehlers dated September 16, 1999, outlining unresolved stormwater issues in the 401/CZM review of Port Of Seattle’s Sea-Tac Airport Master Plan Expansion. Topics include: definitions of ‘modified Level 1’ and ‘Level 2-type flow control’; role of the Des Moines Creek Retention/Detention Facility (RDF) as primary stormwater detention versus wet vaults; pre-existing conditions baseline year (100% till-pasture, 1994 vs. earlier); 10% impervious watershed starting assumption; de-icing/dissolved oxygen report and 303(d) impaired waterbodies in Des Moines Creek and Miller Creek; infiltration rates; construction schedule for detention facilities; water quality BMPs adequacy; and net effect of master plan development on stormwater quality. References 1972 legal settlement between Port Of Seattle and downstream Miller Creek property owners with 1974 baseline. AR 027877–027879.