Regional Water Conservation Still Critical Despite Potential for Increased Rainfall
October 01, 2015
Despite strong El Niño conditions that could generate above-average rainfall in Southern California, the San Diego County Water Authority today…
Despite strong El Niño conditions that could generate above-average rainfall in Southern California, the San Diego County Water Authority today urged residents and businesses to maintain extraordinary water conservation efforts in light of on-going state mandates and continued uncertainty about whether El Niño will deliver significant precipitation to critical watersheds in the Sierra Nevada and Rocky Mountains.
Oct. 1 begins the “water year” for resource managers, the start of the season when snow and rain collects for use the following calendar year. After four years of drought in California, precipitation over the next several months is pivotal for determining water storage levels for key reservoirs around the state and along the Colorado River.
Water year 2015 was the warmest ever for California, according to the state Department of Water Resources. Current projections are for temperatures to remain above average statewide during the fall and winter – conditions that would make it harder to conserve water and could reduce snow levels.
“There’s no guarantee that El Niño will deliver water when and where we need it most,” said Dana Friehauf, a water resources manager for the Water Authority. “Even if we get substantial precipitation statewide, it almost certainly will take more than one wet winter for California to emerge from the current drought, which is among the most severe in recorded history.”
Because of its diversified water supply portfolio, the Water Authority currently has enough water to meet 99 percent of normal year demands. Regardless, due to statewide drought conditions the State Water Resources Control Board’s aggregate water-use reduction target for the region is 20 percent compared to 2013 levels starting June 1. Over the first three months of state-mandated savings, the San Diego region reduced urban potable water use by 27 percent compared to the state’s baseline period of June, July and August 2013.
Regional water conservation is mainly being achieved by reducing discretionary irrigation as residents and business comply with local water-use rules. State-mandated water-use reductions are scheduled to remain in effect through February 2016.
Conserved water in San Diego County is being stored locally for future use, a valuable asset should drought conditions continue into 2016 or beyond. Since May, the Water Authority has stored 42,000 acre-feet of water in San Vicente Reservoir. An acre-foot is approximately 325,900 gallons, enough to serve two typical families of four for a year.
Climatologists say there is a strong likelihood – 95 percent – that El Niños conditions will continue through the winter, and El Niños often – but not always – deliver above-average rainfall to Southern California.
Local rainfall can significantly diminish water demand when residents turn off their irrigation systems. State rules prohibit landscape irrigation during, and for 48 hours after, measurable rain. However, runoff only accounts for a small fraction of the region’s water supplies. During the last strong El Niño event in 1998, local rainfall was 180 percent of average, but even then local surface water only met about 20 percent of region’s water demands.
As a wholesale water agency, the Water Authority coordinates drought response actions for the region. The regional strategy centers on decreasing ornamental landscape irrigation first to minimize the economic disruption caused by cuts to water used by industrial, commercial and farming operations. In May, the Water Authority’s Board adopted a set of measures to help local water agencies meet the state’s water-use reduction targets. It included immediately boosting regional conservation and outreach efforts and restricting irrigation of ornamental landscapes with potable water to no more than two days a week across the region. Member agencies have the flexibility to set their own watering days and times.
For more information about drought conditions, along links to with water conservation resources such as San Diego County Garden Friendly Plant Fairs and WaterSmart landscaping classes, go to whenindrought.org.