Coastal Treatment Plant Export Sludge Force Main Replacement

Coastal Treatment Plant Export Sludge Force Main Replacement

The SOCWA proposes to replace approximately 16,600 ft of two existing parallel 4-in pipelines between the Coastal Treatment Plant (CTP) and Alicia Parkway in Orange County, CA. This project was analyzed within an EIR prepared for the Coastal Treatment Plant Export Sludge Force Main Replacement Project (Dudek 2013). Since that EIR was prepared the SOCWA has proposed improving a section of the creek bank along Lower Aliso Creek to provide erosion protection and improved stability for the existing infrastructure in the area as well as for the proposed force main replacement pipeline. The proposed improvements include constructing three rock groins or dikes at selected locations to redirect flows along the channel bank away from the bank and allow for capture of sediment upstream of the groins/dikes resulting in the build up of sediment at the lower bank. The groin/dikes would extend out from the channel bank approximately 20-ft across the berm to the edge of the low flow channel. The top width of the groins/dike would be approximately 5 ft. The median seize of the dike rock would be 24 inches with a max of 36 in. This improvement allows for natural revegetation along the berm between the groins/dikes and does not require any fill in the low flow channel or removal of existing channel banks. In addition to these stabilization features, the alignment of the pipeline would be slightly revised in two locations.

Laguna Niguel

Orange