September 12, 2011
The Sierra Nevada Snowpack is one of California’s most important natural water reservoirs. The snowpack is formed during the fall and winter and as it melts in the spring and summer (the two seasons when California’s water demand is greatest), slowly releases about 15 million acre-feet of water. Because of its role in the water supply within California, changes in its formation and melting cycles can play a major role in the economy, infrastructure, and land development of the state overall.
The 2011 snowpack made headlines for its large size; over the winter it developed to 165% its average size, momentarily putting Californians at ease about their water demands being met. This good news comes after years of smaller snowpacks and subsequent droughts. Yet even in a year when the snowpack is projected to meet California’s water needs, there is still cause for concern.
Though it is well known that the size of the snow pack varies, recently there have also been changes in the pack’s melting cycle. Research published in 2008 suggests that the rate at which the snowpack melts has been increasing annually. So much so, scientists predict that by 2100 the snowpack will melt completely a full two months earlier than it does now. Current infrastructure, dams and other water storage and transportation facilities, have been built to best deal with the previous predictable cycle of snow melt. As the climate changes and temperatures in the area increase, the sudden burst of water earlier than expected and larger than these structures were built for threatens to overwhelm the storage facilities and threatens to increase the risk of both floods and waters shortages. Uncontrolled floods and the inability to properly store water from a mass runoff endangers development and the economy in that it threatens to damage development, which render the dams and other storage facilities useless, and after the runoff has ended suddenly there is little water left over for the seasons in which it is most desperately needed.
Land in the Sierras has long been considered prime for development. Since 1973, some 800,000 acres of woodland have been converted to new land uses. It has been projected that by 2040 almost 20% of private forests in the area will be affected or altered by even more development. More development would add more greenhouse gas emissions and increase erosion and runoff, all changing the behavior of the snowpack further. Development and industry could also introduce pollutants to the snowpack, as they have in the past.
The ecosystem accounts for approximately $2.2 billion of commodities and services annually. In 2005, agriculture production in California counties using Sierra Nevada water was valued at more than $18 billion. Any change or damage to the Sierra Nevada ecosystem has dramatic repercussions for tourism /recreation, agriculture and resource extraction opportunities. The water resources themselves contribute more than 60% and yield 65% of the developed urban and rural water supplies for California. In addition, the Sierra is also home to one of the greatest areas of biodiversity, and many rare organisms.
The main strategies for preserving the Sierra snowpack recently have been greenhouse gas emission reduction and water conservation and recycling. The fact remains, however, that the population of California continues to grow while their main water supply source does not. The steps proposed by the California Department of Water Resources can only counteract the observed changes in the snowpack’s melting cycle, but even a healthy snowpack will reach a point where it cannot meet California’s growing needs.
About the authors: Makena Crowe and Minda Monteagudo are working towards their bachelor’s degrees in Environmental Studies and Political Science, respectively, in the USC Dana and David Dornsife College of Letters, Arts and Sciences.