Notes
Exhibit AR022151 from the PCHB Third Runway EIS proceedings. Appendix A sections 2.6–2.7 of the Comprehensive Stormwater Management Plan for Seattle-Tacoma International Airport (STIA) Master Plan Update Improvements, dated December 2000, project number 556-2912-001. Covers the 49-year hydrologic record (October 1948–September 1996) used for flood frequency and flow duration analyses, including NOAA hourly precipitation records for STIA and daily pan evaporation data from the Puyallup Experiment Station obtained from King County DNR. Section 2.7 details calibration of HSPF PWATER parameters for 1998 embankment fill material using the Hydrocomp Forecast and Analysis Model (HFAM), with Table A-4 listing calibrated values for LZSN, INFILT, INFEXP, DEEPFR, BASETP, UZSN, AGWRC, INTFW, LZETP, IRC, AGWETP, CEPSC, NSUR, LSUR, and SLSUR. Simulated versus observed runoff volumes for February 1999 differ by approximately 0.5 percent (6.83 vs. 6.87 acre-feet). Also references Miller Creek, Walker Creek, and Des Moines Creek HSPF model calibration, SDW subbasin changes, North Employee Parking Lot (NEPL), Cargo subbasins, North Cargo and North Snow Melt Pump Stations, and SDN2 IWS system.