RES 2026039 - Laserfiche WebLink

City of Pleasanton—Hidden Canyon Residences and Preserve Project Final EIR Responses to Written Comments FirstCarbon Solutions 3-125 https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/EIR/4 - Final EIR/21480016 Sec03-00 Responses to Written Comments.docx flow would be directed into 10 drainage management areas (DMAs) with 10 associated bioretention areas. The proposed bioretention areas are Low Impact Development techniques, consistent with the County’s NPDES permit and the Clean Water Program Stormwater C.3 Guidebook, that allow for stormwater infiltration into the soil and detain stormwater on-site in order to reduce peak flows and prevent erosion and siltation. These bioretention areas would be designed in accordance with all applicable standards with adequate capacity to accommodate stormwater flows at the project site. All excess runoff from these bioretention areas would be directed into the on-site storm drain system which would direct flow into the existing 12-inch storm drain line beneath Dublin Canyon Road via new proposed 18-inch and 12-inch storm drains. All new proposed storm drainage facilities would be sized and designed with sufficient capacity to serve the proposed project. Furthermore, as noted in Draft EIR Section 3.6, Geology and Soils, the proposed project would be required to comply with Municipal Code Section 9.14 which requires construction projects to conform to the C.6 Construction Site Control Requirements in the San Francisco Bay Regional Water Quality Control Board’s MRP (Order No. R2-2022-1108; NPDES Permit No. CAS612008). The C.6 Construction Site Control Requirements mandate construction projects that disturb more than one acre of land to file a Notice of Intent and prepare an erosion/pollution control plan or SWPPP to obtain a Construction Stormwater General Permit. The SWPPP or erosion control plan will identify site specific BMPs that will implement erosion, run-on and runoff, and sediment control measures to prevent the discharge of sediments. These BMPs may include scheduling and timing of grading (soil- disturbing) activities, timely revegetation of graded areas, use of hydroseed and hydraulic mulches, and installation of erosion control blankets. Sediment control may include properly sized detention basins, dams, or filters to reduce entry of suspended sediment into the storm drain system and watercourses and installation of construction entrances to prevent tracking of sediment onto adjacent streets. Pollution prevention practices may include designated washout areas or facilities, control of trash and recycled materials, covering of materials stored on-site, and proper location of and maintenance of temporary sanitary facilities. Compliance with the City’s Municipal Code Section 9.14 would ensure that impacts related to erosion and drainage would be less than significant. This comment is included in the administrative record and will be provided to the decision-makers for review and consideration. The comment did not provide new, substantial evidence with respect to the disposition of significant environmental impacts evaluated in the Draft EIR. Therefore, no further response is required. Response to T.VINSON 1-6 As noted in Draft EIR Section 3.3, Biological Resources, page 3.3-2, average annual rainfall is approximately 16 inches and stormwater runoff readily infiltrates the site’s soils; when field capacity has been reached, gravitational water drains into the seasonal drainages and the creek on-site as shallow groundwater or as surface sheet flow, which then flows into Devaney Creek. As stated in Draft EIR Section 3.9, Hydrology and Water Quality page 3.9-20, the majority of the 130.98-acre site would be left as undeveloped open space and existing drainage would not be modified outside of the approximately 7.4 acres of proposed impervious surfaces. Additionally, as stated on Draft EIR page 3.3-41, the proposed project would include the construction of an 18-inch outfall that will drain into the west side of Devaney Creek and a 24-inch outfall that drains into the east side of Devaney Creek near the vicinity of Dublin Canyon Road. The applicant will need to comply with all State and federal regulations related to construction work that will impact aquatic habitats occurring on the