El Portal Sewer Replacement
Phase 1 includes trunk main replacement in Old El Portal, replacing 1,770 linear feet (lf) of 15-inch sewer main and 9 manholes (MH), which carries all Yosemite Valley flows, and closed circuit video inspection of the trunk main from the Park boundary to the El Portal Waste Water Treatment Plant and the Yosemite View Lodge. Phase 1 will also rehab/repair "urgent" areas in Old El Portal area associated with the trunk main replacement including 545 lf of 6-inch gravity pipeline replacement, 773 lf of 4 to 6-inch pipelining of existing pipelines, 176 lf pipe abandonment, 3 spot repairs, replacement of 17 MHs, and repair of 22 MHs.
Phase 2 addresses the remaining deficient segments in Rancheria Flat, the trailer park, and Old El Portal service areas, and includes approximately 2,000 lf of 4 to 6-inch gravity pipeline replacement; approximately 9,000 lf of 4 to 6-inch existing pipelining; approximately 2,000 lf of pipe abandonment; approximately 70 spot repairs; replacement of approximately 20 MHs; repair of approximately 150 existing MHs; removal and replacement of the Bulk Plant and Store lift stations and the associated force mains; rehabilitation of the Motor Inn, Foresta Road and trailer park lift stations; and replacement of approximately 8,000 lf of 4-inch service laterals. Phase 2 work also includes root removal and aggressive cleaning of the gravity pipelines, final condition assessment/as-builts of the entire El Portal sewer system (approximately 53,000 lf) and wastewater treatment plant upstream re-alignment.
This phased project rehabilitates the existing El Portal sewer collection system (predominately constructed in the late 1950s to the early 1960s). The project is a response to the 'failure' rating received from a 2006 condition and capacity assessment. The work is necessary to fix failing sewer lines and prevent sewage spills that infiltrate into ground water and drain into the Merced River. Specifically, the sewer system has gravity mains within 75 feet of the wild and scenic river and a force main passing under the river. The project is essential to ensure compliance with an order issued in 2000 by the California Regional Water Quality Control Board directing Yosemite National Park to prevent sewage spills from the system.