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Update on the California Drought: : August 30 – September 12, 2016
From the Pacific Institute’s California Drought Response Team
Looking Forward to Water Supply Alternatives
The California State Water Resources Control Board released a draft report on the feasibility of regulating direct potable reuse of recycled water. The report concludes that it is feasible to begin the process of developing regulations, but that regulations can only be adopted once certain research and knowledge gaps have been addressed. The report contains a series of recommendations, such as the formation of technical workgroups to develop uniform water recycling criteria.
Direct potable reuse (DPR) uses advanced water purification technologies to recycle wastewater and return potable water — water that is safe for drinking and food preparation — to the distribution system. The use of DPR dates back to the 1950s when the City of Chanute, Kansas adopted the technology to provide emergency water supplies during its six-year drought. More recently, Wichita Falls, Texas used DPR as an emergency measure for about 12 months in 2014/2015 to combat an extended drought.
In Other News
- A climate prediction update indicates that La Niña may not emerge this winter. According to the National Oceanic and Atmospheric Administration’s Climate Prediction Center, the probability of climate-neutral conditions (i.e., conditions near the long-term average) are now predicted at 55% to 60%. This suggests that the chance of La Niña occurring is 40% to 45%.
- California Governor Jerry Brown signed another drought bill (SB184) into law, prohibiting excessive water use during a drought emergency. Violators may face a fine of up to $500 for every unit (748 gallons) of water excessively used. SB184 also requires urban water suppliers to identify and restrict excessive use through one of two methods: the adoption of an excessive water use ordinance or the establishment of a rate structure that includes tiers, water budgets, and penalties or surcharges for excessive water use.
- Statewide water conservation for July fell to 20%, representing an 11 percentage point drop from last July’s achievement. Cumulative savings from June 2015 through July 2016 were about 1.9 million acre-feet, or 24% compared to the same period in 2013. The July results varied across the state, with some agencies (e.g., Anaheim, Malibu, and Vallejo), showing a significant decrease in conservation, and others (e.g., Sacramento, Beverly Hills, and Fresno) maintaining strong conservation efforts.
- A Stanford-led study found that human-caused greenhouse gas emissions may be driving the trends of extremely warm winter days in the western United States and extremely cold winter days in the East. The occurrence and severity of these “warm West/cool East” winter events increased significantly between 1980 and 2015. The warming of winter days will have negative effects on California, which depends on a healthy snowpack to provide about 30% of the state’s water supply.
- For the first time since the beginning of the drought in 2012, California’s agricultural revenue fell by nine billion dollars (adjusted for inflation) between 2014 and 2015, a decrease of 22%. Losses were most pronounced in dairy, rice, corn, cotton, fruit, and nut sectors. It is unclear how much of this loss is related to the drought. Overall, U.S. agricultural revenue fell by $45 billion in 2015, a decrease of 12%.
- This year, California’s cotton acreage has expanded despite the ongoing drought and last year’s drop in revenue. The 35% growth over the 2015 level pushed the total cotton acreage up to almost 220,000 acres statewide. Cotton farming is on a downward trajectory since at least 2000, when statewide planted cotton acreage was about 920,000 acres. Since then, statewide planted acreage has continued to fall by 5% annually on average.
- A new study shows a limitation of atmospheric-centric, long-term drought predictions since they overlook the reduction in plants’ water use under the high carbon dioxide conditions associated with climate change. More accurate predictions can be obtained through the use of plant-centric metrics. For example, the atmosphere-centric Palmer Drought Severity Index predicts future increases in drought stress for more than 70% of global land area. With the use of the precipitation minus evapotranspiration (P-E) measure, this area drops to 37%.
California Drought Status
There has been no change to drought conditions over the past two weeks. Severe-to-exceptional drought extends across 43% of the state, while moderate-to-severe drought extends across an additional 41% of the state.
The NOAA’s new September forecast indicates that La Niña may not emerge this winter, as its chance of occurring has fallen below the 50% threshold.
Cumulative precipitation since the beginning of the water year (Oct. 1) has remained the same at near average (40 inches) in the San Joaquin River Basin, above average (57.8 inches) in the Northern Sierra region, and below average (25.8 inches) in the Tulare Lake Basin.
Water levels in California’s major reservoirs (representing 27.3 million acre-feet of storage) remain at 78% of the reported average for this time of year and 46% of the statewide capacity, a two percentage point decrease from two weeks ago. Conditions in particular reservoirs vary across the state, with reservoirs in the north of the state doing better than those further south. For example:
- The water level at Lake Shasta is at 106% of the historical average. Lake Oroville and Folsom Lake are at 76% and 57% of the historical average, respectively.
- The water level at the New Melones Reservoir, another major reservoir with a 2.4 million acre-feet capacity, remains at 39% of the historical average.
- The water level at the San Luis Reservoir hit its lowest level in 27 years in mid-August, and now stands at 47% of the historical average for this date.
- Lake Cachuma, which supplies water to the city of Santa Barbara and other urban areas in Southern California, is still at 7% of its capacity, or 9% of the historical average.
Since the beginning of 2016, 5,829 wildfires have burned about 529,970 acres across the state (as of 9/12/16). The fires have spread by 110,000 acres over the last two weeks. Currently, the Soberanes Fire in Los Padres National Forest is the largest active wildfire in the state, covering more than 100,000 acres. It is larger than the Gap Fire, Cedar Fire, and Rey Fire combined.
Hydroelectric power generation in June 2016 was about 3,300,000 MWh, more than doubling last year’s June production of 1,500,000 MWh. However, hydropower generation is still 15% less than the 2001-2011 average for the same month.
The most recent data on groundwater conditions are based on measurements taken in spring 2016. Maps of spring and fall groundwater level changes can be found here. Parts of the Tulare Lake, the South Coast, and the Colorado River hydrologic regions have experienced groundwater declines in excess of 100 feet.