In order to more closely mimic existing conditions and ensure that the requirement for spread . <br />flows is. satisfactorily addressed, the following condition is warranted: <br />• The applicant shall include level spreaders, consistent with the requirements of the <br />Stormwater Management Manual at all discharge. points from the storm drainage <br />system. <br />Staff also notes that the placement of storm drainage facilities, i.e. outfalls and level spreaders <br />is inconsistent with the purpose of the existing sewer easement located along the easterly <br />property line (Reel 32, Instrument 22964). In order to avoid future damage to private storm <br />drainage facilities resulting from maintenance of the trunk line, the applicant is encourage to <br />locate the proposed stormwater facilities outside of the easement. <br />In regards to EC 9.6792 Stormwater Pollution Reduction, the applicant proposes to utilize <br />pervious pavement surfaces for the parking stalls, site entryway and fire turnaround. For <br />treatment of'runoff from impervious surfaces, the runoff from the site sidewalks and roofs will <br />be treated in 15 rain planters. In order to ensure that the treated runoff will be discharged at <br />pre-development levels, the rain gardens were sized using the City of Eugene Stormwater . <br />Surface Filtration/Infiltration Facility Sizing Spreadsheet. , Runoff from the automobile garage, <br />drive strip and. Common House buildings will.be treated in a 10 foot wide by 58-foot long <br />vegetated Swale located adjacent to the Common House to the east, with a berm at the end of • <br />the.swale acting as a weir to reduce flows to pre-development levels. As noted in the written <br />statement, the swale was sized using the presumptive method. <br />Public Works staff confirms that the proposed facilities are adequately sized to provide both <br />pollution reduction and destination from the development site. The actual facility sizes and <br />design will be more precisely determined during the building permit process and may be <br />smaller or larger, based on actual impervious surface area and any impervious surface <br />reduction techniques or in-kind facilities that may be provided at the time of development, <br />provided they are consistent with the City's 2008 Stormwater Management Manual, and are <br />not materially inconsistent with the approved site review plan. <br />EC 9.6793 Stormwater Flow Control <br />This standard is not applicable as the subject property is below 500 feet in elevation and does <br />not discharge to a headwaters stream, however as discussed above, post-development-flows <br />will be limited to pre-development levels in order to mimic existing conditions because a public <br />storm-water system is not available and on-site infiltration is not recommended strategy. <br />EC 9.6794 Stormwater Oil Control <br />This standard is not applicable because the proposed development will not generate high <br />concentrations of oil and grease. <br />• <br />PDT13-01 Oakleigh Cohousing <br />Page 18 of 22 <br />1272 <br />