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From the Pacific Institute’s California Drought Response Team
The 2016 water year has come and gone. Starting on October 1, 2015 and ending on September 30, 2016, the past water year brought some respite to parched areas in Northern California, which received average to slightly above average precipitation, although precipitation in Southern California remained well below average. In Northern California, spring runoff was significantly below average due to several factors, including the replenishment of depleted soil moisture, increased uptake by vegetation, and less precipitation falling as snow. The Department of Water Resources (DWR) is beginning to describe this low snowpack condition as a “snow drought,” and it is likely to occur more frequently as a result of climate change.
In a new report summarizing drought conditions for the 2016 water year, DWR shows that the 2012-2015 period encompasses the driest four consecutive water years in California since 1895, with statewide precipitation at only 62.2 inches. The second driest four consecutive years was 1917-1920, with 63.1 inches of precipitation, when California had a much smaller population and far fewer acres of farmland.
The forecast for the 2017 water year is still uncertain. The weakened La Niña conditions offer the possibility of a wetter year ahead, but forecasters remain wary. It will take a long time before the end of drought finally arrives as the state needs multiple, consecutive wet winters, and ideally cooler years, to increase soil moisture and allow the mountain snowpack to accumulate.
Despite some grim facts about the drought, California is taking important steps to glean opportunities from this crisis. At the end of September, Governor Jerry Brown signed several water bills that will help prepare the state for future droughts and address ongoing water scarcity concerns. Here is a selection of noteworthy legislation:
There continues to be no change in 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 September forecast indicates that La Niña may not emerge this winter, as its chance of occurring has fallen below the 50% threshold.
The new water year began on October 1. A 1.5-month precipitation outlook (Nov-Dec-Jan) shows a normal precipitation pattern, but it is too early to know how conditions will evolve.
Water levels in California’s major reservoirs (representing 27.3 million acre-feet of storage) have fallen by three percentage points to 43% of the statewide capacity over the past two weeks. Compared to historical data, current storage levels represent 77% of the reported average for this time of year, three percentage points lower than two weeks ago. Conditions in individual reservoirs vary across the state, with those in the north of the state doing better than those further south. For example:
Since the beginning of 2016, a total of 6,645 wildfires have burned over 600,000 acres across the state. The fires have spread by 87,000 acres, or 17%, over the last two weeks. The Soberanes Fire in Los Padres National Forest is still the largest active wildfire in the state, covering more than 130,000 acres and larger than the Gap Fire, Cedar Fire, and Rey Fire combined.
Hydroelectric power generation in July 2016 was about 3,400,000 MWh, representing an 82% increase over last year’s July production of 1,900,000 MWh. However, hydropower generation is still 12% below 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 between Fall 2011 and Fall 2015.
Addendum: A new study, using aerial imagery and geospatial techniques, found that land conversion to almond orchards between 2007 and 2014 increased annual statewide water use for irrigation by 27%. While some orchards were simply converted to almonds from other crops (such as corn, cotton, winter wheat, and tomatoes), others were planted on formerly natural landscapes, including wetlands. The Almond Board has released a statement disputing these findings.