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Lake Forest Woods Sewer and Manhole 36
Owner: Irvine Ranch Water District
Project Location: Lake Forest, California
rvine Ranch Water District (IRWD) operates an existing 10-inch sewer pipeline that services residents in Lake Forest, Orange County, California. The sewer pipeline runs adjacent to San Diego Creek. During large storm events this stretch of the pipeline is at risk of exposure and damage from erosion and under-cutting by the creek. Storms in January 2023 eroded the creek banks at this location and exposed the sewer pipeline and manhole shaft. The sewer pipeline was not fully protected at this location and would likely be damaged from any additional storm events. which would result in spillage of raw sewage into San Diego Creek and impact sewer service to local residents.
This repair was accomplished using Class VII (1/2-ton) ungrouted rip rap over Class II (60 lb) ungrouted rip rap over Type III non-woven fabric. The rip rap was keyed into the creek invert several feet and was placed on a 1.5:1 slope from below the creek bed to the crest elevation.