EXH1128042698

Northwest Regional Office, 3190. 160th Ave S.E. * Bellevue, Washington 98008-5452 • (425) 649-7000 October 21, 1999 Mr. Tom Hubbard Surface Water Program Port of Seattle P.O. Box 68727 Seattle, WA 98168-0727 Dear Mr._bard:r; Re: Port of Seattle, Sea-Tac International Airport Dissolved Oxygen De-Icing Study (Final Draft) Lisa Austin, Tom Luster and I have reviewed the draft final Dissolved Oxygen De-Icing Study submitted by the Port of Seattle on August 16, 1999 in responding to an anticipated 401 Certification monitoring requirement on the impacts of de-icing agents from airport storm water run-off to Miller and Des Moines Creeks. The comments provided below reflect a summary of concerns and criticisms of the study by the three reviewers listed above. The data dearly show large BOD5 discharges to both the NW Ponds and Lake Reba. Considering the relatively rapid transit time through and brief residence time in Des Moines and Miller Creeks, one would expect to see any impacts of BOD5 discharges in Puget Sound and not in the stream systems. To support this conclusion, Streeter-Phelps analyses and modeling on both stream systems should have been conducted. On page 4-9 of the study, there is a discussion of tributary sampling in the Des Moines Creek East Basin which revealed the highest concentration of BOD5 (1,176 mg/1) detected in the study and led the Port to conclude that this was an indication that high BOD5 producing chemicals were being used and discharged into stormwater from elsewhere in the basin. Ecology does not reach…

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Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]