As written here over the last few months, water availability for new development is at the heart of any proposed project. If the Governor, or any of the region’s water suppliers impose increased water restrictions, will serve letters may be in short supply. So, short of a miracle May monsoon season, what can be done to increase the water supply for Southern California and more specifically, San Diego?
The San Diego County Water Authority (CWA), over the last decade, has moved to broaden their (and our) water supply portfolio. Since 90% of the water used in the region is imported, the CWA has been aggressive in finding alternative water supplies as well as increasing water storage facilities.
Storage, or thought of here as reservoirs, allows the CWA to “bank” water from wetter years for times of shortage or drought. In a wet years, local reservoirs have “over topped” the dam that held the water, allowing the excess water to run towards the ocean. By building the Olivenhain dam, raising the dam at San Vincente and sharing in the cost of the Diamond Lake reservoir (and dam), the CWA has increased our “local” capacity to store water for dry years. This forward planning isn’t cheap, but it acts like an insurance policy, paying off in years of drought.
Local supplies are another example of CWA’s forward thinking. The trade with the Imperial Irrigation District to line their canals with concrete so San Diego could have the water lost to infiltration was another prudent investment. The lost water now belongs to the CWA and lessens our dependence on imported supplies from Northern California and the Colorado River. The newest supply source is currently under construction in Carlsbad. The Poseidon desalination plant, when complete, can produce up to 10% of the regional water supply.
Probably the largest untapped water resource is our regional wastewater supply. Ten years ago almost 70% of the regions’ inhabitants were against the “Toilet to Tap” idea for augmenting our regional water supply. Continued drought conditions and a public awareness/education campaign have convinced San Diego County residents that water re-use isn’t a bad idea. In fact water re-use’s time has come.
The San Diego City Council is reviewing increasing the capacity of the demonstration program at the North City Reclamation Plant, located at Miramar Road and I-805. Over the last few years scientists and city plant operators have run a demonstration project where they take treated waste water suitable for irrigation and re-purify that water to potable status. The plan before the City Council is to embark on increasing the capacity of the demonstration program from a million gallons per day to 10 million gallons per day, shipping the water to the San Vincente reservoir for storage and drawing that water to be treated and used in our homes.
Do the math yourself. The region collects and disposes of 300 million gallons of wastewater daily, dumping the treated wastewater in the ocean. The single largest water supply is right here—the water we use daily! San Diego gets almost 50% of its water from the Colorado River where a few hundred municipalities upstream discharge their treated wastewater into our drinking water supply. When you realize the fact that San Diego has been using treated wastewater for over 50 years, the yuck factor is diminished.
San Diego isn’t alone in seeking ways to turn wastewater into potable water. The City of Wichita Falls, Texas has been in a severe drought for years and has turned to using reclaimed wastewater to solve their water supply problem. Click here to read the story in Business Week.
San Diego can choose to be a national model and more water independent by doing what NASA does for the astronauts in the international space station—reusing wastewater as a valued commodity and not just something to use once and dispose of. When you see one of your elected officials, let them know that you support water re-use.