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20150407134324653.pdfMemorandum Date: April 1, 2015 To: City of Edmonds Stormwater Engineering Department Attn: Jerry Shuster From: Nicole Hernandez, PE Project: Former Woodway High School Field Improvements Subject: Response to Comments — BLD20141182 Jerry, 91 1 Western Avenue, Suite 420 Seattle, WA 98104 p. 206.725.121 1 f. 206.973.5344 Ipdengineering. corn Enclosed please find three (3) copies of the updated Stormwater Site Plan and design drawings for the Former Woodway High School Field Improvements. Below is a list of your review comments for the permit re -submittal dated November 11/12/2014 along with our responses which are reflected in the updated plans and report. ® Minimum Requirement # 6/Water quality System Page 12 — The text states that the sizing of the StormFilter® system by Contech is located in Appendix B. This information was not found the review copy of the Stormwater Site Plan, please provide. The 2 -year release rate flowing to these filters is stated to be 0.089 cfs. The modeling in Appendix B has 0.094 cfs, please reconcile. Response: The StonnIter sizing has been refined based on fisrther coordination with Contech. The current sizing also reflects the 2 -year release and the flow rate is consistent between the model output, the storrnwater site plan, and the Contech sizing sheet. The City approves using the ZPG media cartridges at this point. Contech currently has a different cartridge using MetalRxTM media that has "Conditional Use" designation from Ecology. The City only accepts technologies with the "General Use" designation. When the ZPG media cartridges need to be replaced, the City will require the School District to replace them with the cartridges with MetalRxTM media, if they have earned the "General Use" designation by Ecology. Response: Noted. The Stormwater Site Plan has been updated to reflect that the City will require the change in media type to MetalRx once it has been approved far "General Use ". ® Sheet F-2.3, Detail I — The "Site Specific Data Requirements" for the StormFilter® system are blank and should be in the detail, especially the invert elevations and the other elevations. Response: The site specific informationhas now been included in. the StormFilter detail. As mentioned previously in our email correspondence, we have further refined the modeling, flow control structure and gravel storage layer of the field section to maximize the efficiency of the system while still meeting the flow control requirements. Please let me know if you have any questions or need additional information. Thank you. cc: File