(j) EC 9.6791 through 9.6797 regarding stormwater flood control, pollution reduction, flow <br />control for headwaters area, oil control, source control, easements, and operation and <br />maintenance. <br />The applicant has provided a Stormwater Management Plan and Drainage Study prepared by Branch <br />Engineering detailing how runoff from the development will be managed. Stormwater runoff from <br />roofs, driveways, and other impervious surfaces of the development site will be collected in a shared <br />private storm drainage system that will be located within private easements or shared common areas. <br />The runoff from the private development will be detained and released to mimic existing flows and <br />drainage patterns. A stormwater quality facility is proposed to treat the shared driveway. <br />Staff notes that a maintenance agreement for the shared system will be required at the time of the <br />subsequent subdivision review. Additionally, if the private storm system is not addressed in CC&R's, <br />they will need to be covered by private easements. <br />EC 9.6791 Stormwater Flood Control - Existing drainage patterns will be maintained by discharging <br />stormwater runoff created by the PUD through a shared, private spreader system to the unimproved <br />Vivian Drive right-of-way. <br />EC 9.6792 Stormwater Quality - The applicant's proposal to treat the runoff from the proposed <br />shared driveway with a water quality treatment swale is conceptually acceptable, subject to more <br />detailed review for compliance with applicable standards during the building permit process. <br />Treatment for individual lots will be evaluated at the time of building permit review for each lot. <br />EC 9.6793 Stormwater Flow Control (Headwaters) applies to the site given its proximity to a <br />Headwaters stream located on the east side of Vivian Drive. The applicant proposes a detention <br />facility and spreader system, as detailed in the Stormwater Management Plan and Drainage Study, to <br />restrict post-development flows to pre-development rates. <br />EC 9.6794 Stormwater Oil Control does not apply because the development will not trigger any of the <br />applicability standards of EC 9.6794(2). <br />EC 9.6795 Stormwater Source Control does not apply because the proposed development does not <br />include any of the pollution sources specified in EC 9.6793(2). <br />EC 9.6796 Dedication of Stormwater Easements, does not apply because the proposed storm drainage <br />system will be privately operated and maintained. <br />EC 9.6797 Stormwater Operations and Maintenance applies to all facilities designed and constructed <br />in accordance with the stormwater development standards. This section also specifies when, and <br />under what conditions, the public will accept functional maintenance. Consistent with these <br />standards, the applicant proposes private operation and maintenance of the on-site stormwater <br />management facilities. To ensure compliance with EC 9.6797(3)(c), as proposed, the following <br />condition of approval is recommended in the event the Hearings Official approves the proposal: <br />• Final PUD plans shall include the note: "On-site stormwater management facilities will be <br />privately owned and operated. An operation and maintenance plan will be developed <br />Hearings Official Decision (PDT 15-1/ ARA 15-13) 20 <br />