Private Roadway <br />Similar to the system proposed for Capital Drive, the applicant has proposed to collect Stormwater <br />runoff from the private street into a series of underground storage facilities with orifices in order to <br />meet the flow control requirements of EC 9.6793. As shown in Tables 1 and 2 of the applicant's <br />Stormwater Management Plan and Drainage Study, runoff contributed by the construction of the <br />private street will be discharged at Discharge Sites 1, 2, and 3. For the northern and southern <br />portions of the proposed private street, runoff will be collected into underground detention vaults <br />with orifices that will reduce the peak discharge rate that are less than or equal to pre- <br />development conditions. Water will then connect into the proposed public system where it will <br />discharge at the locations identified in the Stormwater Management Plan and Drainage Study. <br />Tables 1 and 2 show that the peak discharge rate at Discharge Site 1 will be less than that under <br />existing conditions, and the peak discharge rate at Discharge Site 3 will be equal to that under <br />existing conditions, consistent with EC 9.6793(3)(a). <br />For the remaining portion of the private street, runoff will be directed into a series of underground <br />storage tanks with orifices that will reduce the peak discharge rate. Runoff will then be released <br />through level spreaders into a designated preservation area on the east side of the development <br />site. Based on existing topography, the proposed system closely mimics existing runoff locations. <br />The discharge location is identified as Discharge Site 2 in Tables 1 and 2 of the applicant's <br />Stormwater Management Plan and Drainage Study. As shown in Table 2, the peak discharge rate <br />being released out of each level spreader mimics that of the existing conditions. It is noted in the <br />report that a 38-foot wide section was used to establish the existing basin and its peak discharge <br />rate of 0.16 cfs. The proposed system includes two (2) 38-foot wide level spreaders, each being 38 <br />feet long and each having a peak discharge rate of 0.16 cfs, which matches the existing condition. <br />Staff concurs that this is consistent with the flow control standards outlined in EC 9.6793(3). <br />Individual Lots <br />The applicant has stated that individual lots will address flow control and water quality standards <br />when applying for building permits on a case by case basis. Staff concurs that the flow control <br />standards for the individual lots will be addressed on a case by case basis at the time that each lot <br />applies for a building permit. <br />EC 9.6794 Stormwater Oil Control does not apply because the proposed development will not <br />result in any of the conditions listed under EC 9.6794(2) (a)-(d). <br />EC 9.6795 Stormwater Source Controls does not apply because this application will not result in any <br />of the site uses or characteristics listed under EC 9.6795(2) (a)-(h). <br />EC 9.6796 Dedication of Stormwater Easements. The applicant has proposed to place a portion of <br />the public storm line on the north end of Capital Drive within a 10 foot wide Public Utility Easement <br />on the east side of the right-of-way. The proposed storm pipe is 24" in diameter and is designed to <br />increase the storage capacity of the storm water system. Due to existing grades within the right of <br />way, there will not be adequate cover over this proposed pipe. In order to achieve proper cover <br />over the pipe, the applicant has proposed to direct the pipe alignment outside of the right-of-way <br />to the east, where there will be adequate cover over the detention pipe. <br />Capital Hill PUD (PDT 17-1) Page 20 of 22 <br />