On the heels of several dry years, the highly unusual and extremely dry water year of 2013-14 has made every Californian aware that we are experiencing a drought. But it is far from the first. Historical rain data (since 1851) records severe drought in the late 1880s, 1928-34, and 1987-92. Combining this with historical ecology data (tree rings, sediment, and other natural evidence) it becomes clear that California precipitation is highly variable from year to year, and that the 20th century was a wetter than average era. In light of this extreme variability, our water systems should be as efficient as possible and have built-in mechanisms and policies that retain water during wet years for use during dry years. In reality, California’s water system-built in the 20th century and arguably the most complex in the world-is highly wasteful and promotes distributing the maximum possible amount of water during wet years with little regard for future dry years.
The cornerstone of water harvesting in California is the capture of vast quantities of freshwater from the snowpack and major streams that flow west out of the Sierra Nevada and into the Sacramento and San Joaquin Rivers and Delta. The inefficiency is a result of a water storage and delivery system that loses significant quantities of water through evaporation from massive surface reservoirs and thousands of miles of open canals. The technology and know-how exists to avoid these losses through underground storage-by directly recharging depleted groundwater aquifers in the Central Valley and by restoring mountain meadows that mimic the function of reservoirs by slowly releasing water in the summer from their deep sand substrates. End use of water in California is also highly inefficient. Eighty percent of captured freshwater is used by agriculture, which generates only three percent of the state’s economy. Cheap, subsidized water has created an artificial market in which the state’s most precious resource is dedicated to some of the least valuable crops. Focus on higher value crops that require less water (almonds instead of alfalfa, vegetables instead of cotton) and avoiding farming in desert areas like the western San Joaquin Valley (which gets only four inches of rain per year) would significantly improve efficiency of our end use.
The other problem is that California’s water is severely over-allocated, making it impossible to adequately reserve water for the inevitable and consistent arrival of dry years. In California, we have both real water and “paper water.” Although water is legally enshrined as belonging to the people of California as a “public trust” resource, a complex and arcane system allocates public and private entities a “water right” to store and deliver specified quantities of surface water to serve prescribed “beneficial uses”-such as municipal use, irrigation, hydropower production and environmental purposes. This legal arrangement dates back to the Gold Rush, with a “first in time, first in line” seniority system that, in dry years, gives special privileges to entities that have held surface water rights since before 1914. And the problem is not just overallocation of surface waters: California’s groundwater resources are almost entirely unregulated and vigorously exploited.
A major contributor to California’s water woes-Delta ecosystem collapse, species extinctions, and polluted rivers-is the fact that today we have significantly more “paper” water than real water. Indeed, allocations of surface water in the Sacramento and San Joaquin River watersheds amount to roughly eight times the average annual streamflow-and even three times the highest streamflow on record. A study by the California Department of Water Resources acknowledged that water used to maintain basic river health conditions are last on the priority list: whereas urban and agricultural water use generally varies by no more than 10-20 percent between wet and dry years, so-called “environmental water” allocations can drop by over 50 percent during droughts.
As our current drought continues, Californians will be forced to cut back their water use significantly or pay a much higher price for each gallon. Each person can engage in a wide range of water conservation activities that we’ll cover in future articles (graywater harvesting, rain water catchment, and drought tolerant landscaping to name a few).
