Public Comment (8) - Laserfiche WebLink

APP-28 The key finding above is that the development will provide onsite detention, so that the development is not adding stormwater runoff to open waterways. With regard to the onsite waterways, the HO's conclusion that the development does not impact on-site waterways is based on the assumption that the previous criterion at EC 9.8325(5), regarding slope, has removed the eastern portion of the site from development. The HO did not evaluate the applicant's.initial 75-lot site plan against the stormwater approval criteria at EC 9.8325(7)0) or EC 9.8325(13); however, the June 21, 2012 staff report provided an analysis and found that the eastern portion of the site did not meet either approval criterion. The topography of the site creates two distinct drainage basins, which coincides with the analysis of the western portion of the site, separate from the eastern portion. The staff analysis of the stormwater development standards at EC 9.6791 through EC 9.6797, invoked by criterion EC 9.8325(7)(j) is as follows: Western Drainage Basin The western portion of the site shows a piped stormwater system extended from Martin Street within the proposed streets, with an interconnecting piped system between the streets at the northwest portion of the site, corresponding to gravity drainage and site topography, and involving a piped crossing of the westerly waterway. The proposed stormwater pipes located outside the streets are proposed within public utility easements (PUE). If the Hearings Official ultimately approves the application, the staff recommendations regarding acceptance and determination of the final PUE locations at EC 9.8325(7)(b), as well as waterway crossings and grading restrictions are applicable here, as are staff's proposed conditions regarding compliance with other public improvement standards. The available information indicates that the receiving system has the capacity to accommodate addition runoff from the proposed development.. Staff concurs that the proposed development complies with the stormwater destination standards of EC 9.6791. As noted in the Hydrology Report, a downstream deficiency for the future 10-year storm previously existed at segment 65344 - 66656 in Martin. Street. The completion of Capital Projects AM06A and AM06B under City Project Number 3951 (i.e., City Contract No. 2007-09) has corrected these deficiencies. No other downstream deficiencies in the Amazon Channel, which is the receiving system for the proposed development, have been identified for the 10-year design storm, per modeling in the 2002 City of Eugene Stormwater Basin Master Plan, Volume II of VI for the Amazon Basin. Eastern Drainage Basin The applicant has not provided sufficient information regarding the capacity of this drainage basin to accommodate the proposed stormwater runoff from the contributing development along Canyon Drive. The applicant's plans Final Order - Deerbrook PUD (PDT 12-1) December 17, 2012 Page 27 30