SR 06:242 - Laserfiche WebLink

Urban Stormwater Runoff The applicant will install a bio-retention pond - approximately 20,000 square feet in area - on the east side of Lot 1 with the first construction phase to pretreat the development's storm water runoff before entering the City's storm system. The bio-retention pond is required to be main- tained by the development's homeowners association. Stormwater runoff from the public street and all lots will be conveyed to the bio-retention pond by "V"-ditch and by underground piping. The applicant's proposal is reflected on the develop- ment plan and in the draft conditions of approval. The development's storm water runoff meas- ures will be shown in detail with the tentative subdivision map for review and approval by the Planning Commission. The project will be required through the grading and building permit and construction processes to incorporate best management practices to control erosion and to prevent discharges into the City's storm drain system resulting from this development. Regional Water Ouality Control Board Regional Water Quality Control Board (RWQCB) staff met with City staff and the applicant on the site to discuss the project's grading, existing swales/seeps, urban stormwater runoff mitiga- tion measures, etc. R WQCB staff considered the overall proposal - grading, treatment of swales/seeps, bio-retention areas, etc. - to be sensitive to the site with its impacts reduced to a less-than-significant -level. The only issue identified by the RWQCB staff requiring further analysis and potential mitigation is the 20 linear feet offill proposed at the end of the southernmost swale/seep before it enters the culvert on the west side of Foothill Road. However, RWQCB staff believes that this fill may be mitigated by the proposed planting of native trees and habitat planting along the three swales/ seeps - totaling approximately 700 linear feet, a 35 to 1 mitigation ratio - shown in the land- scape design guidelines. Another potential mitigation measure would be to bypass this area with underground piping, thereby avoiding the proposed fill this area. Since this issue is isolated to a relatively small, 20-foot section of the existing swale/seep, staff believes that this issue can be resolved by the applicant, City staff, and the RWQCB staff at the tentative subdivision map for review by the Planning Commission. Staffs recommendation is reflected as a draft condition of approval. Based upon the on-site meeting and discussion, the RWQCB staff indicated their comfort with the project going forward to the Planning Commis- sion. View Analyses View analyses on discs are attached showing the before/after views of the project from various vantage points. The view analyses include: Item 6.c., PUD-58 and PGPA-ll Page 26 of 34 August 23. 2006