3_Exhibit C_ADDENDUM ONLY - Laserfiche WebLink

City of Pleasanton—Stoneridge Mall Residential Project Section 15183 Checklist/15164 Addendum CEQA Checklist FirstCarbon Solutions 129 Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480017/Consistency Checklist/21480017 Stoneridge Mall Residential Project Checklist Addendum_Updated.docx the proposed project would not result in a new or more severe adverse impact that was not previously identified in the Prior EIR. ii) Surface Runoff Resulting in Flooding On-site or Off-site? Prior EIR Conclusions The Prior EIR determined that buildout of the Housing Element would involve construction activities, which may disturb soils and result in alteration of site topography. However, buildout under the Housing Element would be subject to RWQCB Construction General Permit requirements, including preparation of a SWPPP. Compliance with these measures would ensure that development under the Housing Element would not result in an increase in surface runoff at the development sites. In addition, provision C.3 of the ACCWP NPDES Permit requires that projects with more than one acre of impervious surface submit a Hydromodification Management Plan to demonstrate that development would not increase long-term runoff rates on a property beyond existing conditions. Therefore, with conformance to existing regulatory requirements, the Prior EIR concluded that buildout of the Housing Element would have less than significant impacts with respect to surface runoff. Analysis of Proposed Project The proposed project would follow the standards established by provision C.3 of the ACCWP NPDES Permit during project implementation and operation. These measures would ensure that the proposed project does not result in an increase in surface runoff resulting in flooding on or off-site. Additionally, the project site currently contains 239,773 square feet of impervious surfaces consisting entirely of paved areas and parking. The proposed project would reduce the amount of impervious surfaces to 220,438 square feet. In addition, the proposed project would construct a new storm drainage system with multiple bioretention areas, inlets, underground piping, and landscaping that would capture and slow down runoff and route it to existing storm drain lines on Stoneridge Mall Road to the south and east of the project site, thus reducing peak runoff rates on the project site (Exhibit 9). The storm drainage system would be required to be designed in accordance with the requirements and specifications of the Pleasanton Municipal Code Chapter 9.14, Stormwater Management and Discharge Control. Impacts would continue to be less than significant, and no mitigation is necessary, consistent with the Prior EIR. There are no proposed changes, new circumstances, or new information that would cause new or more severe impacts. Therefore, there are no environmental effects that are peculiar to the proposed project or the parcels on which the proposed project would be located. Impacts would be less than significant and the proposed project would not result in a new or more severe adverse impact that was not previously identified in the Prior EIR. iii) Capacity of Existing or Planned Stormwater Drainage Systems or Additional Sources of Polluted Runoff