San Diego County water officials said Monday the region should have plenty of water in the coming year, even though there is lingering concern about water coming from the Colorado River basin.
The San Diego County Water Authority (SDCWA) said local customers are reaping the benefits from decades of effort to diversify and secure water supplies.
“Because we’ve invested. We’ve done the work — in our infrastructure, in our reliability and in conservation,” said Efren Lopez, a water resource manager with the SDCWA.
It has also helped that local water use is down more than 40% since 1990.
Per capita water use was at 235 gallons in 1990, but that has fallen to 126 gallons in 2022. Low-flush toilets, low-flow showerheads and less water use for landscaping all get credit.
“As a county we’ve been conserving water for over 35 years, and we’ve reduced water use by (nearly) 50%. Those are incredible numbers and that is what keeps us really reliable,” said Lopez.
The SDCWA has built dams to increase local water storage, relined pipes, encouraged use of recycled water for landscaping, and built a large desalination plant in Carlsbad. That plant can create 50 million gallons of drinking water a day.
The city of San Diego is also investing billions in a plan to recycle the city’s sewage and turn it into drinking water, creating another local supply.
Even so, more than 60% of the region’s potable water still comes from the Colorado River, according to the water authority.
Most of that river water comes from a long-term transfer deal with the Imperial Irrigation District that was made possible when the landmark Quantification Settlement Agreement was signed in 2003. That deal cleared the way for rural to urban water transfer purchases.
But the water supply in the Colorado River has been challenged by a long-running drought.
Federal officials became so concerned about water levels in Lake Mead and Lake Powell, two of the west’s largest reservoirs, that in 2022 they asked California, Arizona, and Nevada to voluntarily cut back the amount of water they pulled from the river.
California is conserving about 400,000 acre feet of water, less than 10% of its allocation. San Diego is not affected because the local water authority buys most of its Colorado River water from the Imperial Irrigation District (IID). The IID has some of the most senior water rights on the river and they would be cut only after cuts come to other water users.
But the federal government fears users are taking too much water from the river, and the U.S. Bureau of Reclamation has suggested mandating cuts in water users’ allocations if levels of Lake Mead and Lake Powell continue to drop.
Mandatory cuts could affect San Diego.
“If there was an actual cutback — not a voluntary reduction — but if there was an actual cutback to Imperial Irrigation District supplies, we would share in approximately 6.5% of that. So, a very small percent,” said Alexi Schnell, the Colorado River Program Manager at the SDCWA.
Some of the pressure to cut water use from the Colorado River eased this year because of rain and snow in the river basin, but long-term trends point to drier conditions that stress water supplies.
