Private Roadway <br />The applicant has proposed three (3) discharge locations for the runoff of the proposed private <br />roadway. The first discharge point is for the southern portion of the private roadway, which will be <br />collected by catch basins or a trench drain and will enter an underground detention tank. From <br />here, the runoff will then be discharged into the eastern gutter line south of the intersection via a <br />bubbler. The second discharge point for the private roadway is located at the bottom of the <br />conservation area between Lots 13 and 14. Runoff for this drainage basin will be collected into <br />various underground storage tanks that will reduce the peak discharge rate and releasing in into <br />the eastern conservation area west of the Ribbon Trail, via level spreaders. The third discharge <br />point is for runoff along the northern portion of the private roadway. This runoff will be collected <br />into a series of underground storage tanks and discharged into an existing drainage ditch north of <br />the proposed development site. <br />Individual Lots <br />For the lots bound by the new roadway improvements, upon treatment and flow control, drainage <br />disposal will discharge onto the new roadways. For the lots draining away from the roadway to the <br />east, disposal will be into level spreaders directed toward the existing park land to the east or <br />north. These locations are consistent with existing drainage patterns. <br />The proposed system has been designed so that discharge will occur at locations that mimic <br />existing conditions and at rates that are less than or equal to existing rates. The results from <br />infiltration testing confirms that the soils (Hydrologic Groups C and D) mapped at this site are not <br />appropriate for on-site infiltration, which is why the applicant has proposed a series of <br />underground mechanical forms of collection, detention, treatment, and discharge. Staff confirms <br />that the proposed detention system demonstrates conceptual compliance with this standard and <br />EC 9.6791(3)(b)(2), subject to a more detailed review for compliance with applicable standards <br />during subsequent permit reviews. <br />EC 9.6792 Stormwater Quality <br />In order to reduce runoff pollution and mitigate the volume, duration, time of concentration and <br />rate of Stormwater runoff from the development, the applicant must select, size, and locate <br />stormwater quality facilities from the Stormwater Management Manual to treat the stormwater <br />runoff from the proposed development. As noted previously, the application includes the widening <br />of an existing public street as well as the construction of a private street. <br />Capital Drive <br />The applicant has stated that the additional road widening of Capital Drive is too small to justify the <br />cost of water quality treatment, and therefore has proposed no treatment facilities for this portion <br />of the project. This is inconsistent with Eugene Code, as stated in EC 9.6792(3)(b), which requires <br />infiltration, filtration, or mechanical facilities to treat the runoff of a proposed public street. For <br />compliance with this standard, the following condition is warranted: <br />Capital Hill PUD (PDT 17-1) Page 18 of 22 <br />