PC-2025-16 - Laserfiche WebLink

Hana Japan Restaurant Project Initial Study/Mitigated Negative Declaration 53 May 2025 Management Practices (BMPs) to control or minimize pollutants from entering stormwater and must address both grading and erosion impacts, as well as non-point source pollution impacts of the project. Because the proposed project would disturb greater than one acre of land, the proposed project would be subject to the requirements of the State’s General Construction Permit. In addition, the project would be required to comply with Chapter 9.14, Stormwater Management and Discharge Control, of the City’s Municipal Code, which includes standards for managing stormwater runoff. Pursuant to Section 9.14.130, construction sites shall implement effective erosion control, run-on and runoff control, sediment control, any appropriate active treatment systems, good site management, and non-stormwater management through all phases of construction until the site is fully stabilized by landscaping or the installation of permanent erosion control measures. Therefore, the proposed project would not discharge sediment or urban pollutants through soil erosion, violate any water quality standards or waste discharge requirements, or otherwise substantially degrade surface or ground water quality during construction. Operation The proposed project would not involve operations typically associated with the generation or discharge of polluted water. Following completion of project buildout, disturbed areas of the site would be largely covered with impervious surfaces and topsoil would no longer be exposed. However, the addition of impervious surfaces on the site would result in the generation of urban runoff during project operations, which could contain pollutants if the runoff comes into contact with vehicle fluids on parking surfaces and/or landscape fertilizers and herbicides. All municipalities within Alameda County (and the County itself) are required to develop more restrictive surface water control standards for new development projects as part of the renewal of the Countywide NPDES permit. As discussed throughout this IS/MND, on-site drainage is currently captured by a drainage ditch bisecting the project site. Project construction would remove the on-site drainage ditch, thereby changing the existing drainage pattern of the site. However, pursuant to Section 9.14.140 of the City’s Municipal Code, the City of Pleasanton has adopted the County C.3 Stormwater Standards, which require new development and redevelopment projects that create or alter 10,000 or more sf of impervious area to contain and treat all stormwater runoff from the project site. A total of approximately 40,601 sf of impervious surfaces would exist on site following development of the proposed project, including 6,438 sf of rooftop surfaces. Thus, the project would be subject to the requirements of the C.3 Stormwater Standards related to stormwater treatment, which are included in the City’s Municipal Regional Stormwater NPDES Permit. In addition, the proposed project would be subject to Sections 9.14.080 and 9.14.120 of the City’s Municipal Code, which establish standards for stormwater discharge. Compliance with such requirements would ensure that impacts to water quality standards or waste discharge requirements would not occur during operation of the proposed project. In order to manage and treat stormwater, the project site would be divided into 21 drainage management areas (DMAs) (see Figure 6). Stormwater runoff within the project site would flow primarily to IMP-1 and IMP-2 at the eastern and western ends of the site, as well as the proposed landscaped areas and bio-retention areas located throughout the project site, which would vary between six and 15 feet wide. Infiltration through the permeable materials within the bio-retention areas would occur through the pervious landscaping areas. The project site would also include installation of silva cells beneath the parking