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20150727124918.pdfCraig Chaney Architect July 13, 2015 Jennifer Lambert, Engineering Division City of Edmonds Public Work Department 1215 th Avenue N. Edmonds, WA 98020 Re: BLD20150239 — Engineering Plan Review Comments 1 Kemper Residence 9303 Olympic View Drive Dear Ms. Lambert, The above referenced permit plans were submitted originally without knowledge of the platted setbacks unique to this parcel. Per the City's determination the parcel was approved with a 12.5' front yard setback and a 30' setback from the platted top of slope. The original house design did not fit on the site within the revised setbacks, so it has been redesigned to be consistent with these setbacks and the documents have been revised accordingly. The house is slightly smaller to accommodate the reduced buildable area, and the garage has been reduced in size as well to fit within the setbacks. The main portion of the house shifted up the hill toward the easement about 7' or so, increasing the area between the bluff and the house. In addition, the site drawings have been revised in their entirety to address the concerns outlined in your plan review. Your comments have been addressed specifically as follows: GENERAL: The site drawings have been revised and configured as requested. The utilities have been removed from the plot plan and relocated to the Stormwater plan as requested. (Please note that the City's Plot Plan handout asks for the utilities to be on the plot plan.) The Grading and TESC plans have been combined into a single plan. Also, the consolidated architectural site plan has been removed from the plan set, to reduce confusion. The City's requirement for the site plans to be at 1:20' scale does not provide enough detail for the final design, which is why the additional drawing was included in the original application. It has been removed, and I will provide it to the contractor for construction purposes only. 8314 NE 120th Street, Kirkland, WA 98034. 425.802.5331 TEMPORARY EROSION CONTROL PLAN: Items 1), 2) and 3): The referenced details have been added to the set and referenced on the Grading/TESC plan. See Sheet A1.2. 4) The request note has been added. Sheet A1.2. WATER: 1) A Fire sprinkler system is required. I've shown the water line from the meter location (where we believe the City will require it to be located -Item 2) to the house. The meter size, and water line size and type have been noted. The tracer wire note was added. The required 3' separation between the water line and dry utilities has been noted on the plans. See A1.1, Stormwater/Utility Plan. SEWER; 1) The sewer main is shown. See Stormwater/Utility Plan for all, Sheet A1.1. 2) The sewer service is shown to the house. 3) The pipe size and material is shown. 4) The required cleanout is shown on the edge of the easement as requested. The cover is specified on the drawings. 5) The cleanout is shown within 2' of the house. 6) The invert elevations are shown as requested. STORM: 1) The footing drains that can provide a minimum of 1% slope to the invert elevation will discharge to the stormwater detention system. Footing drains below the minimum slope will drain to the sump and lift station, to be discharged to the stormwater system. 2) The retaining wall footings below the stormwater invert and footing drains that cannot make the invert with a 1% slope will drain to a sump and lift station. See A1.1 and detail 3/A1.1. 3) The owner intends to utilize the existing detention system. a.) I've visually inspected the system and all entrance and exit points are open, flowing and clear of debris. There is no significant sediment evident in either catch basin and at the entry points of the storage pipe. There are no indications that the system isn't functioning correctly. The owner is sourcing a company to do an inspection and report. Since there is no visual indication of system malfunction we request that the system verification report be made a requirement of permit issuance, or of CO, so that the plan review can continue while the investigation is underway. b.) The owner proposes to use permeable paving to keep the impervious area below the 5000 sf threshold, but is looking at the option of using conventional detention techniques to detain the additional 725 sf of impervious area, should we switch to that strategy. 4) As noted above the owner intends to use permeable paving to keep the impermeable area below 5000 sf. Details for the permeable paving, including specifications have been included. See Sheet A1.1. The proposed paver is porous enough to be used as an alternate to a drain grate. The permeable paving design will allow storm water in the permeable area to infiltrate such that there will be no standing water on the surface, replicating the current unimproved site condition. Note that because the building moved up the hill the grades have been reduced and there is no permeable pavement proposed beyond a 10% slope. The Soils engineer is investigating the infiltration rate of the site, and the owner is considering the option of increasing the impervious area to above 5000 sf and changing the site classification to a Small Site, Category 2, and employing a civil engineer to design the additional detention system and evaluate the downstream impact. I would like to discuss the implications of these options with you. 5) Rim and invert elevations have been indicated as requested. DRY UTILITIES: 1) The 3 foot required separation is shown on the Stormwater/Utilities plan, as requested. These revisions and the additional information should address the issues raised in your review. If you have any questions please don't hesitate to contact me. R t a ards, Craig S. Chaney