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by Sarah Stevens

Surf, sun, beach, and water—ocean as far as the eye can see. San Diego is synonymous with great beaches and the Pacific Ocean. While 31 million tourists enjoy visiting with the temperate year-round climate and beautiful ocean views and 3.1 million residents call San Diego home, most of us pay little attention to the actual lack of water in San Diego. The region imports 80% of their water from the Colorado River and Sacramento Bay Delta.

The city’s almost complete reliance on outside water sources is risky and can lead to significant shortages and price increases in the face of droughts, natural disasters, or regulatory restrictions. The San Diego Water Authority has made it their priority to reduce the county’s reliance on outside water sources. On November 29, the Authority Board voted 85% in favor of the 30-Year Water Purchase Agreement from the Carlsbad Desalination Plant, under which the Authority will purchase 56,000 acre-feet of water per year starting in 2016.

In 1991, the San Diego Water Authority relied on imports for 95% of its total water supply.

In 2012, the water supply has been significantly diversified with only 45% imported from the Metropolitan Water District.

After a severe drought in the 1990s San Diego’s water supply was cut by 31%. For a county importing more than 80% of its water supply, a 30% reduction was a serious threat. And as we see everyday, shortages mean higher prices. If a drought 20 years ago resulted in such a significant of a cut back, imagine the consequences of a drought today. The gradual climate warming will have a very dramatic effect on our water supply and the price we pay for it.

By 2020, the Water Authority’s goal is for the Carlsbad Desalination Plant to produce about one-third of all water produced in San Diego. This would result in a reliance on outside water sources of less than 30%. (FYI: through diversification over the last 20 years, the San Diego region’s per capita water use is 37% less than in 1990.)

Desalination: A Background

As detailed in a previous post on clean drinking water in the U.S., desalination is the process of reverse osmosis to remove salt from seawater (or dissolved minerals from groundwater) to create freshwater. Although the technology has advanced, early civilizations used similar methods to produce drinking water while on long sea voyages. According to the San Diego Water Authority and desalination supporters, the Agreement provides the region with a secure, plentiful water supply.

The Carlsbad Desalination Plant will be the nation’s largest desalination plant, producing up to 50 million gallons a day by 2016 and 8% of the area’s total water supply by 2020. Located on the Pacific coast next to the Encina Power Station in Carlsbad, the plant will connect to the San Marcos Aqueduct using a 10-mile pipeline.

Desalination: Impacts

While the Agreement promises to provide San Diego with a more secure water supply, not everyone supports it. There are environmental, energy, and economic challenges to be considered.

Removing salt from seawater seems like a reliable, cost-effective water supply process, but as we have learned, the environmental impacts must be considered from the outset. Desalination creates a salty brine. Although the brine can be returned to the ocean where it can be diluted, careful monitoring is crucial to ensure there are no adverse effects to the fish and wildlife.

Other opponents argue that desalination only provides a short-term solution to the looming water shortage. In the next 15 years 1.8 billion people are expected to live in areas of extreme water shortages. Some opponents stress the importance of water conservation and management.

Opponents of this technology and the plant also argue that the desalination process requires high energy usage and continued reliance on fossil fuels. Reverse osmosis is an energy intensive process. (renewable energy, solar and wind powered, desalination plants have been built, but on a much smaller scale.)

In terms of cost to local residents, rates for water are expected to increase $5 to $7when the Authority begins to purchase the water. Water produced by the Carlsbad plant will be sold to the Authority at $2,042 to $2,290 per acre-foot of water, which is approximately double the price of imported water. However, the Authority and desalination supporters believe that the increased cost is small compared to the projected future rates of imported water.

Finally, opponents also question if demand for desalinated water will remain steady. While the demand for clean, freshwater will not diminish, similar plants built in Australia and Florida are currently operating below capacity due to cheaper alternatives. The Charles Meyer Desalination Plant in Santa Barbara was built in the early 90s as a temporary emergency water supply after a severe drought; however, since completion in 1992, heavy rains have left the facility on standby.

On the upside, the Agreement has a number of clauses protecting the Water Authority. Poseidon Resources, the private investor-owed development firm is responsible for all construction costs and risks, totaling $700 million (excluding financing and Authority improvements). In fact, the Authority does not pay until Poseidon’s desalinated water meets rigorous quality and quantity standards. The testing of the desalinated water is expected to begin in 2015 and the water will be ready for sale in 2016.

In addition, the total price of desalinated water is fixed—increases in water costs are only valid due to inflation and other predetermined and limited circumstances.

Plant backers also argue that construction will benefit the local economy; Poseidon expects to create 2,300 jobs.

While there’s no clear yes or no winning argument, desalination provides San Diego and other areas across the world with freshwater using available natural supplies.