Notes
Exhibit 307 (AR 020465–020467). Draft meeting notes from October 30, 2001 low flow analysis meeting for the 401 Permit post-issuance clarification process, Sea-Tac International Airport Third Runway. Prepared by Kate Snider, Floyd Snider McCarthy, Inc. Attendees included Ann Kenny (Dept. of Ecology), Kelly Whiting and David Masters (King County), Lisa Scott (Corps of Engineers), Keith Smith and Robin Kordick (Port of Seattle), Paul Fendt (Parametrix), Joe Brascher (Aquaterra), Pony Ellingson (Pacific Groundwater Group), and Felix Kristanovich (Foster Wheeler). Documents five modeling errors and revisions: (1) 1/24th conversion factor error in embankment fill input to HSPF causing embankment flow contribution to be 24 times previous value; (2) incorrect daily AGWO vs. hourly AGWI input files for embankment modeling by Aquaterra; (3) revised approach to modeling impervious area at embankment filter strips using AGWI and SURO time series data; (4) switch from 2-d to 1-d version of Hydrus model; (5) addition of infiltration basin discharge modeling for Miller Creek basin. King County raised concern that approximately 8 acres of Walker Creek embankment (of ~16 acres total) appears in both the Hydrus embankment model and HSPF stream model. Email cover from Kelly Whiting (King County) to Kathryn Snider dated October 31, 2001 transmitting comments on Walker Creek embankment areas.