SCH Number 2005111101

Project Info

Title

Lake Murray Trunk Sewer Replacement / Relocation and Permanent Access Path

Description

DFG is intending to execute a Lake and Streambed Alteration Agreement pursuant to Section 1602 of the Fish and Game Code (SAA # 1600-2010-0164-R5) to the Permittee, City of San Diego, Engineering and Capital Projects. The Permittee proposes to alter the stream to replace 14,543 linear feet of the Lake Murray Trunk Sewer with larger diameter pipe and construct permanent access to manholes located along the side mains that connect to the trunk sewer. The existing trunk sewer includes 12-, 15-, and 18-inch diameter pipe, which will be replaced with 18-, 21-, and 24-inch diameter pipe. The project will require a 30-foot wide temporary construction easement along the trunk sewer through Chaparral Canyon and a 40-foot wide temporary construction easement through the rest of the trunk sewer alignment. Construction methods for sewer pipe replacement include cut and cover and tunneling. A permanent eight-foot wide access route to manholes on the trunk sewer line below Lake Murray dam in Chaparral Canyon will be created during construction, mostly along an old overgrown access route. Access paths to most of the manholes west of Lake Murray were constructed during an emergency maintenance and repair project that occurred December 2002 through January 2003. Improvements to these existing access paths will include creating circular or hammerhead turnarounds at several of the manhole locations. Access paths will also be created to manhole Nos. 100, 101, and 102 south of Jackson Drive, to Manhole No. 55 south of Navajo Road, and to Manhole Nos. 27, 279, and 285 on an ornamental slope between the Mission Trails Golf Course and residential development west of Cowles Mountain Boulevard and south of Navajo Road. Additionally, an aluminum staircase will be constructed to provide foot access to Manhole No. 272 at the southern end of the Project off of Del Cerro Boulevard. A concrete-lined drainage channel occurs along much of the trunk sewer alignment, with a portion, approximately 970 linear feet, that appears to be unlined and supports wetland habitat. Intermittent sections of the concrete-lined channel, and one-half (the half of the channel closest to the pipeline) of the unlined channel section, will be impacted during the proposed construction activities. Water flowing within the concrete-lined drainage channel will be diverted using a by-pass pump, and will be allowed to flow back into the channel past the area of construction. Following completion of the trunk sewer replacement, sections of the concrete-lined drainage channel that were impacted will be replaced.

3 documents in project