Beginning this fall, the San Elijo Joint Powers Authority will begin a project to replace the land outfall pipeline that originates at the San Elijo Water Reclamation Facility and connects to the ocean outfall at Cardiff State Beach. The 30-inch inside diameter pipeline conveys on average 10 million gallons per day (up to 25.5 million gallons per day) of treated wastewater from the cities of Encinitas, Solana Beach, and Escondido for ocean discharge approximately 1.5 miles from shore. The land outfall was constructed in 1965, and due to its age and the surrounding soil type, is estimated to be at the end of its useful life. Pipeline failure would likely have both environmental and financial impacts. To date, the SEJPA has not experienced wastewater spills associated with the outfall, and keeping the pipeline in good operating condition is of utmost importance to the agency. The replacement pipe material is high density polyethylene (HDPE) with an anticipated useful life of 100 years. The project is being constructed with the review and approval of seven local, state, and federal agencies.
The process includes trenchless technology or horizontal directional drilling (HDD) to avoid impacting the lagoon. The HDD launch site will be located on the beach and the new pipe will connect to the existing ocean outfall pipe located approximately 15 feet below ground level at the beach.The HDD process involves drilling a pilot hole along the designated directional path from an entry point.The second stage involves enlarging the pilot hole to a diameter suitable for installation of the pipeline.The third stage consists of pulling pre-fabricated pipeline back into the enlarged hole from the directional drilling exit point to the entry point and ultimately to the point of connection. The dewatering activity on the beach will include baker tanks, separation plant and temporary storage trailers.
Two construction staging areas are required, one at the beach and one at the San Elijo Water Reclamation Facility.The staging site on the beach is approximately 250 ft. by 100 ft. rectangular area to accommodate the HDD launch site.The southbound lane on Coast Highway 101 will be reduced to one lane with a temporary bike lane and a reduction in parking.Construction will occur over a period of approximately 4 - 6 months.
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