San Antonio Backup Pipeline Project (Town of Sunol Pipeline Project)

San Antonio Backup Pipeline Project (Town of Sunol Pipeline Project)

Background On September 20, 2012, the San Francisco Planning Commission certified the San Antonio Backup Pipeline Project Final Environmental Impact Report (final EIR) and the San Francisco Public Utilities Commission (SFPUC) subsequently approved the project (San Francisco Planning Department file number 2007.0039E). The approved project analyzed in the EIR involves the construction of several new facilities and improvements to: 1) provide reliable conveyance capacity for planned and emergency discharges of Hetch Hetchy water out of the SFPUC regional water system under future flow conditions, and 2) provide increased operational flexibility and delivery reliability during emergencies and planned maintenance activities. The approved project includes, but is not limited to, the following: • Installation of approximately 1.3 miles of pipeline from Alameda Siphon Number 3 near the San Antonio Pump Station, along the west side of Calaveras Road and beneath the San Antonio Creek channel, to a new discharge facility. • Construction of a discharge facility just south of San Antonio Creek. • Construction of the Alameda Creek Pump Station, including an electrical control building, and transfer pipeline. • Replacement of a 5,700-foot-long section of 12-inch-diameter potable water pipeline to the Town of Sunol. • Relocation of a 1,325-foot-long section of potable water pipeline and 1,400-foot-long section of raw water pipeline on the north side of San Antonio Creek. The SFPUC proposes to modify the approved project. The modified project (referred to as Town of Sunol Pipeline Project, case number 2007.0039ENV-03) proposes to replace an approximately 495-foot-long segment of the existing 12-inch-diameter water distribution pipeline, which serves as the primary source of potable and firefighting water for the unincorporated Town of Sunol. The original pipeline was installed in 1941 and replaced in 1963 with a concrete encased pipe situated below the Arroyo de la Laguna creek bed. Over time, erosion and incision of the creek has exposed the pipeline leaving it unsupported and vulnerable to collapse due to its own weight or damage from debris during high-flow events. The purpose of the modified project is to improve the safety and reliability of the existing water distribution pipeline to meet SFPUC's objective of providing potable and firefighting water to the Town of Sunol. The Town of Sunol water distribution pipeline is a part of the potable water system addressed in the San Antonio Backup Pipeline Project (the approved project) described above. However, the proposed location of the modified project is outside the project boundaries of the components previously evaluated in the EIR for the approved project. Specifically, the ElR addressed replacement of a 5,700-foot-long section of the potable water pipeline along the western side of Calaveras Road, whereas the modified project focuses on replacing a different portion of this pipeline system at and near its crossing of the Arroyo de la Laguna. In the modified project area, the pipeline alignment extends east from the paved parking lot of Sunol Glen Elementary School, through the school's track and field facilities, across Arroyo de la Laguna, underneath Pleasanton Sunol Road, and then continues to the eastern side of Pleasanton Sunol Road. A portion of the modified project would be on land at Sunol Glen Elementary School.

Town of Sunol

Alameda

San Francisco Bay Area

Alameda, San Francisco