Desalination Plant


In Spanish, Agua Hedionda literally means "stinking water". This was an accurate description of the stagnant lagoon before the Encina Power Station was commissioned in 1952. For over 50 years, the operators of the power plant have regularly maintained the lagoon and dredged an opening to the ocean to sustain a source of seawater to cool the power plant's generators. As a result, today the 388-acre Agua Hedionda Lagoon is a man-made, shallow coastal embayment teeming with marine life and an array of recreational and educational activities, and environmental research. The lagoon supports a thriving marine ecosystem and is home to the Hubbs-SeaWorld fish hatchery, the Carlsbad Aquafarm, YMCA Camp and the Lagoon Foundation's Discovery Center. The seawater cooled power plant is expected to be decommissioned in the coming years, leaving the lagoon without an entity responsible for its long-term maintenance. Locating the new seawater desalination plant next to the Encina Power Station solves this problem. The operators of the desalination plant will assume responsibility as the Agua Hedionda Lagoon's steward, providing long term maintenance and dredging, once the power plant is decommissioned.

Once built, the desalination plant will ensure the continued stewardship of the Agua Hedionda Lagoon and the surrounding watershed, and will guarantee for many years to come that the citizens of Carlsbad will be able to enjoy the benefits of this clean lagoon and its surrounding beaches.

The Agua Hedionda Lagoon is a man-made, shallow, coastal embayment that is wholly owned by Cabrillo Power LLC. Since 1952 the Lagoon has been kept open to the Pacific Ocean by routine maintenance dredging. The EPS site was determined to be a desirable location due to its close proximity to the ocean, compatible land use and the availability of the existing intake and outfall.

The location of the desalination facility within the Encina Power Station was specifically selected so as not to conflict with the City of Carlsbad Redevelopment Plan goals related to facilitating the conversion and relocation of the existing power plant and enhancement of commercial and recreational opportunities.

The site of the desalination plant is a 6-acre parcel in a portion of the site that leaves the majority of the EPS property open for potential recreational or redevelopment activity at some future date.

The desalination facility will conform to the 35 feet height limit in the Local Coastal Plan and the building design has been enhanced to ensure compatibility with future land use in the area.

Onsite improvements would include an intake pump station, and pipeline, concentrate return pipeline, sewer connection, electrical transmission lines, road improvements, and product water pump station and pipeline.

The desalination facility is connected to the discharge channel of the Encina Power Station at two locations. The intake pump station is connected to the upstream portion of the discharge channel and delivers 100 million gallons per day (mgd) of seawater to the desalination facility. Half the seawater processed by the desalination facility would be converted to high quality drinking water. This water is delivered to Carlsbad and the surrounding communities.

The remaining water, 50 mgd of seawater with an elevated salt content, is returned to the discharge channel where it is diluted with additional seawater prior to being discharge to the ocean. This ensures that the increased salinity will not impact the marine organisms in the vicinity of the discharge channel. 

Site diagram

Flow Schematic 2012 (2)