RES 07100 - Laserfiche WebLink

Piur/icn Drive Turnout and Pipeline Project Eavironmeutrrl Ckecklist impervious surfaces in the area, and no substantial loss of groundwater recharge potential will occur. Groundwater levels in the project area were encountered during exploratory borings along the pipeline alignment at depths as shallow as 5 feet below ground surface to 15 feet below ground surface (DCM Engineering 2005). The geotechnical engineering investigation report for the project (DCM Engineering 2005) indicates that the groundwater levels along the project alignment should be expected to fluctuate based on factors such as seasonal rainfall, flow in nearby drainages, nearby construction operations, proximity to existing utility trenches containing porous granular backtill, and leaks in underground utilities. Based upon the results of the borings, the geotechnical investigation (DCM Engineering 2005) concluded that groundwater may be encountered during excavations for the project, including the pipeline. If groundwater is encountered during excavations, dewatering activities will follow the City of Pleasanton Stundard Specifications a~~d Details (2002) as discussed in the Project Description. All groundwater removed from excavations will be desilted prior to discharge into the storm drain system through filtering materials and methods meeting the Association of Bay Area Governments Standard for Erosion & Sedimentation Control Measures and/or through methods and procedures described in the California Storn~ Water Best Management Practice Handbook-Construction Activity. Therefore, impacts to groundwater would be less than significant. c, d) Less than Significant. "fhe project facilities will not substantially alter the existing drainage patterns within the construction area or adjacent areas. The pipeline will be buried under Pimlico and Brockton drives, and the trenches will be repaved to preconstruction conditions and no changes to the existing drainage patterns or increase in impervious surfaces will occur. Construction of the fluoridation building, Zone 7 turnout, City of Pleasanton vault and Santa Rita control valve vault will result in approximately 2,450 square feet or 0.06 acre of increased impervious surfaces in an already built out urban area and will not substantially alter existing drainage patterns in the area. This small increase in relation to the urbanized project area will not change storm water infiltration rates from that addressed in the City of Pleasanton 1996 General Plan Update (City of Pleasanton 1996) or the Environmental Impact Report for the 1996 General Plan Update (Mundie and Associates). Further, the small increase will not substantially change the amount of impervious surface coverage in this urban built out area, nor increase or contribute nmoff water that would exceed the capacity of the existing or planned storm water drainage system. No additional storm drain capacity is needed for the project. g, h) No Impact. The project is not within the 100-year flood hazard area of the City of Pleasanton (City of Pleasanton 1996 General Plan Update E1R 1996). 1'hc project does not involve placing housing within a 100-year flood hazard area. i) No Impact. The project does not involve construction of a levee or dam and would not place people or structures at significant risk of loss injury or death related to flooding. Therefore, this would be no impact. City of Pleasanton 37 Winzler & Kelly Draft Initial Study/Proposed Negative Declaration August 2006 04263$01