7000 HARDESON RD 2018-01-02 MF Import

JUL 24'96 16:59 FR W & H PACIFIC 20S 822 5341 TO IZ0625988ZS P.03i09 VdafUJV� ~LIC If'f W rS MEMORANDUM TO: Al Lockc/Cordon Witcher FROM: Jane Zimmerman DATE: June 3, 1996 SUBJECT: Drainage Calculation/Compost Filter Review, Community Transit IIowtiout A latter s6o I+q be sent to the City from the applicant indicating how much of the available 4.43 aces feet of regional atormwater detention will be used to satisfy stormwater detention requirements for this site. Owners of currently undeveloped parcels of the Merrill Crock site (that were originally a part of the Seaway Center Binding Site Plan, SEPA ,f30-90) should receive copies of the letter. ]� A copy of the operations and maintenance manual, referred to on sheet 6.4 of the civil plan set, must be provided to the City for review, approval, and future reference. The testing results the City currently his appear to be for the original compost bed treatment configuration. I have some concerns about the effectiveness of the radial filters, particularly with respect to the linear distance stormwater will flow through the compost media. If test zesults exist for the radial cartridge configuration, they should be submitted with the drainage calculations. At the very least, the applicant should indicate the distance of the flow path thrrnigh the radial filter as opposed to other treatment configurations for which monitoring of pollutant removals has occurred. To satisfy the conditions of the DNS for this project and City standards, the removal efficiencies of the treatment system should be at least as good as expected for a T wetpond designed in accordance with City standards. J-. pit not h8vc cope of -'}' labcra -cry ru.5 ea r cb, w•+ti ,es, -)Pc der. 07/24/96 16:52 TX/RX N0.0327 P.003