• The final PUD plans shall note the requirement that, at the time of development, all <br />stormwater discharge points directed toward the City's property shall be designed as level <br />spreaders, consistent with the City's 2008 Stormwater Management Manual. All <br />stormwater facilities shall be located outside the public wastewater easement along the <br />east property line. <br />In regards to EC 9.6792 Stormwater Pollution Reduction runoff from the proposed impervious <br />surface areas will primarily be treated in planters (about 15 scattered throughout the <br />development site). To ensure that the treated runoff will be discharged at pre-development levels, <br />the rain gardens (planters). were sized using the City's Stormwater Surface Filtration/Infiltration <br />Facility Sizing Spreadsheet. Runoff from the garage, driveway, and common house will be treated <br />in a vegetated swale (approximately 10 feet wide and 58 feet long) located east of the common <br />house. A proposed berm at the end of the Swale will act as a weir to reduce flows to pre- <br />development levels. As noted in the applicant's written statement, the swale was sized using the <br />City's 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 facilitysizes and design <br />will be more precisely determined during the building permit process and may be smaller or <br />larger, based on actual impervious surface area and any impervious surface reduction techniques <br />or in-kind facilities that may be provided at the time.of development, provided they are consistent <br />with the City's 2008 Stormwater Management Manual, and are not materially inconsistent with <br />the approved final site plan. <br />EC 9,6793 Stormwater Flow Control is not applicable because the subject property is below 500 <br />feet in elevation and does not discharge to a headwaters stream. However, as discussed above, <br />post-development flows will be limited to pre-development levels, in order to mimic existing <br />drainage conditions. EC 9.6794 Stormwater Oil Control is not applicable because the proposed <br />development will not generate high concentrations of oil and grease. EC 9.6796 Dedication of <br />Stormwater Easements does not apply becau.se the proposed stormwater facilities are to be <br />privately operated and maintained. <br />EC 9.6797 Stormwater Operation and Maintenance applies to all facilities designed,and <br />constructed in accordance with the stormwater development standards. This section also specifies <br />when, and under what conditions, the public will accept function maintenance. Consistent with <br />these standards, the applicant proposes private operation and maintenance of the on-site <br />stormwater management facilities. To ensure compliance with EC 9.6797(3)(c), as proposed, the <br />following condition of approval is necessary: <br />The final site plan shall note: "On-site stormwater management facilities will be privately <br />owned and operated. An operation and maintenance plan will be developed consistent <br />with the City's Stormwater Management Manual, and notice of this plan will be recorded, <br />during the building permit'process." <br />With the findings, conditions, and future permit requirements noted above, staff finds that this <br />criterion will be met. <br />Staff Report: Oakleigh Meadows Cohousing September 2013 Page 26 <br />HO Agenda - Page 33 1013 <br />