EXH0236A018958

PCHBPollution Control Hearings Board of the State of Washington

"- 16300 christensenroad, suite350 vancouver |EXHIBIT NO_| seattle, washington98188-3418 edmonton I "_- 5- o-_.._ | (206)(206)439-2420241"6000--laxPh°ne seattle • M. Green W July 31, 2000 U.S. Army Corps of Engineers Regulatory Branch Post Office Box 3755 Seattle, Washington 98124-2255 ATTN: Jonathan Freedman, Project Manager Washington State Department of Ecology Permit and Coordination Unit Post Office Box 47600 Olympia, Washington 98504-7001 ATTN: Tom R. Luster, Environmental Specialist Subject: Approval process for stormwater management plan for proposed 3rd runway ..... development actions at Seattle-Tacoma International Airport. Northwest Hydraulic Consultants (nhc) has been retained on behalf of the Airport Communities Coalitionto provide a technical review of stormwater facilities and related streamflow impacts from the proposed 3rd runwaydevelopment at SeaTac airport. By a letter dated November 24, 1999, we provided our initial comments from our technical review of documents describing the Stormwater Management Plan (SMP) for Master Plan Update Improvements at Seattle-Tacoma International Airport. By a letter dated May 3, 2000, we provided follow-up comments resulting from our technical review of additionalmaterials which were not availableat the date of the initial review. The purpose of this letter is to remind you that the numerous substantial comments raised by us and by ." others have, to our knowledge, not yet been satisfactorily addressed, and to express concern over what has become a closed-door design review process. Independenttechnicalreviewsby otherexpertsundercontractto the Departmentof Ecologyhave consistentlycorroboratedour concerns. A limited-scopereview by Pacific GroundwaterCroup1 foundserious"fundamentalquestions"in thehydrologicmodelingwhich, if leftuncorrected,would haveledto theconstructionof facilitieswhich would be generallyundersizedandwould not achieve the requiredlevelsof flow control. A broader-scopereview…
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