"The fact that the spring water on
its own could fill half of Shasta's stagnant capacity in one year drives home the point of the enormous volumes flowing from the springs."
- Drew Braugh, CalTrout North Coast
Regional Director
On average, the total discharge from the area's springs flows at 3000 cubic feet per second and contributes nearly 700 billion gallons annually to Shasta Reservoir. After passing through Shasta and flowing into the Central Valley Project, the water that originates in the volcanic springs accounts for about 20% of the summertime flow in the lower Sacramento River. At a market value of $700 per acre foot, this spring flow represents an annual one billion dollar asset for the state.
Andrew Braugh, the Mt. Shasta/Klamath Program Director for CalTrout, offered another perspective on the contributions of the volcanic springs to our water supply. "Over two million acre-feet per year of spring-sourced water flows from the region's aquifers into Shasta Reservoir, which is equivalent to half of the overall capacity of the reservoir. Although water is constantly flowing through Shasta from both spring and surface runoff sources, and the total volume of water passing through Shasta in a normal or wet year might be in the range of 8 million acre feet, the fact that the spring water on its own could fill half of Shasta's stagnant capacity in one year drives home the point of the enormous volumes flowing from the springs." Scientific studies have shown that spring-fed rivers resist variance in volume and temperature better than watersheds that rely mostly on surface runoff, such as the rivers flowing west out of the Sierra Nevada. In drought years, the spring-fed rivers of the Shasta region help to offset the deficit caused by decreased snowmelt and account for a higher percentage of the total annual storage of Shasta reservoir (representing between 14 and 30% of the total volume of water passing through Shasta during a drought year).
During our severe drought of the past four years, the cold water provided by springs has helped to stave off potentially disastrous losses of downstream endangered fish, agricultural productivity, and hydropower: in effect, the spring water became our emergency reserve. Climate change is predicted to cause more frequent and intense droughts, shift precipitation to less snow and more rain, and increase temperatures in California. These climate trends make the cold flow from the aquifers even more critical to our water supply and aquatic species resilience. In addition to the large volumes of water, the spring water has a unique chemistry that is ideal for the health of the area's rivers. As rainfall and snowmelt filter through the volcanic rocks, they pass through a layer of sedimentary rock and absorb a unique blend of nutrients composed primarily of nitrogen (N) and phosphorous (P). By the time the water percolates to the surface, it contains an ideal mixture of nutrients that promotes rapid growth of aquatic plants, insects, and fish.