California’s multi-year drought is one of many extreme weather stories dominating national headlines this winter, and it doesn’t appear to be letting up any time soon. While we’ve been pummeled by snow and ice out here on the East Coast, 2013 was driest year on California record, and despite a recent winter storm of near biblical proportions, California’s reservoirs and snow pack remain far below average as we approach 2014’s dry season. According to UC Berkeley’s Lynn Ingram, tree ring analysis suggests that California may be experiencing its driest weather since A.D. 1580!
As of March 4, California’s snowpack (accounting for one-third of the state’s water supply) remained at 33 percent of average. Selected reservoirs reported on the California Department of Water Resources website are cumulatively at 60 percent of average storage for this time of year. These extreme conditions have led to the declaration of a statewide drought emergency. They have also brought California’s persistent water scarcity out from behind the policy curtain and into the forefront of public debate. In response, on March 1 California Governor Jerry Brown signed a $687 million drought relief plan that aims to accelerate funding of local and regional projects to increase water supplies in communities hit hard by the drought. The plan includes $472 million in accelerated grant funding for water conservation and recycling programs – investments in California’s “virtual river” of alternative water supplies that are desperately needed in the arid state whose surface and groundwater supplies are already over-subscribed.
While at first glance these storage numbers may not sound too severe, statewide statistics can obscure more extreme local fluctuations, even with California’s extensive north-to-south water distribution system. In fact, several California communities are at acute risk of running out of water within 60 days. Additionally, sparse water supplies have reduced freshwater dilution, leading to increased groundwater contamination risks. In California, this issue is particularly significant in rural areas where water can become contaminated with nitrates due to fertilizer runoff and mismanagement of waste from confined animal feeding operations.
Unfortunately, these extreme fluctuations in water availability and quality are likely indicative of future climate trends, which predict more variability and further uncertainty in future water supplies. The Southwestern United States is expected to experience more extreme drought and rainfall events, leading to increased runoff and reductions in long-term storage. Combined with increased evaporation due to rising temperatures and decreased snowpack storage, it is clear that as the state look towards the future, investments in alternative water supplies – including recycling, storm water capture, and conservation – are critical components to future infrastructure investments. In fact, at the local level, many water districts in California are already planning to aggressively diversify their water supply sources.
To help guide investments and public planning decisions, the most ubiquitous measure to assess water scarcity is the U.S. Drought Monitor. Established in 1999, the U.S. Drought Monitor is a composite index that incorporates climatic, hydrologic and soil conditions, as well as reported impacts and observations from more than 350 contributors across the country. Climatologists from the Monitor’s partner organizations analyze data and produce a weekly report and map of drought conditions, which is available on their website.
For the week of February 25, the U.S. Drought Monitor categorizes 26 percent of California as being in “Exceptional Drought,” while 74 percent of the state is in Extreme Drought and 91 percent severe drought.
In addition to communicating water scarcity to the public and decision makers, the U.S. Drought Monitor has been critical in the decision to distribute state emergency funding toward water conservation and recycling. In fact, it is frequently used to distribute billions of dollars of federal and state relief aid, to trigger drought response policy measures, and to publicize drought through the media. Additionally, the crowd-sourced nature of the index can serve as a model for future indicators that aim to compile geographically sensitive data sources. Continuing to monitor data and indicators of water supply in California – as well as trends indicating changes to historic water supply availability - will continue to be critical in informing California water policy for years to come.
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration. Map courtesy of NDMC-UNL.