Climate Change and Water Supply Analysis

Submitted by the Sierra Nevada Alliance

Problem: Climate change is predicted to reduce the Sierra spring snowpack by 25-40% in the next 25 to 40 years and as much as 75-90% by the end of the century. Not only do Sierra’ rivers supply over 65% of the state’s developed water supply – but Sierra snow acts like the largest reservoir in California. Snow holds water and slowly melts over the spring and summer, releasing this water into 22 major river systems. Our current reservoirs are operated on these 22 major rivers to often release the winter waters and thereby provide space behind the reservoir to prevent flooding. Later, these reservoirs capture the spring snow melt’ water. This snowmelt water is then let out of the dams in the late summer and fall for urban and agriculture water uses.

Wrong solution: Build more dams. One proposal to address a reducing snowpack that a few people are jumping to is to build more dams. While it sounds simple, this is not the smart solution. California has already placed hundreds of dams on 23 of 24 major Sierra river systems and taken the best locations for dams. Trying to build more dams will be extremely expensive economically and extremely problematic environmentally. We have already lost 90% of the salmon in the Sierra due to dams and all our fishery health will be severely threatened with a few more dams. Economically and environmentally, new dams are a bad investment.

Our problem is not a shortage of dams. Our problem is how we prioritize operating and investing in the entire river system from the Sierra to the Sea.

Sierra to the Sea: Smart Path Water Solution

The majority of California’s water goes through a series of steps that all provide opportunities to provide water for the future despite less snow and potentially greater winter rain events.

Step One: Sierra Meadows and Forest Restoration and Protection. The name of the water supply game is ‘capturing water’ and storing it in the high Sierra to slowly release later in the late spring and summer for water supply needs below. While snow is a great capture and storage system – functioning meadows and forests also slow water runoff by capturing and storing the water in Sierra soils. Meadows are ‘wetlands’ and healthy forests are also storage systems. The Feather River has made tremendous progress in preventing fast water runoff by restoring high Sierra meadows – which from historic uses had dried up and were no longer working well. The result of these management measures has been and needs to be a watershed that acts like a sponge and retains water, rather than shedding rain rapidly.

Step Two: Dam Re-Operation. The dams of the Sierra have been operated for a number of years with a limited set of objectives. New re-operations are demonstrating that increased weather and hydrological monitoring can better predict when water really needs to be released to aid flood control and when it can be captured for water supply. In addition, engineering changes to the existing dams have allowed them to better manage for ecosystem health (such as maintaining cold water for releasing for fish migrations) and other needs. All these new efficiencies in operation are and could be providing better protection and more water when we need it.

Step Three: Better flood plain management. Providing more floodplain storage space, more floodway space, and even trying to reduce flood damages by designing flood system “circuit breakers” localizes problems within an overall system and preserves key urban areas and facilities. These space focused measures are not costly and not environmentally damaging structural solutions. Local governments can ensure people avoid vulnerable areas or relocate out of flood prone locations, both of which reduce property damage and threats to life. Identifying appropriate floodplain uses and activities that are compatible with the natural risks means using zoning, subdivision regulations, building codes, emergency preparedness, insurance, and other measures to guide people and communities away from potentially disastrous flood problems. Floodplain management means substituting “management” for “construction” as the most crucial measure for protecting people and property.

Step Four: Water Conservation. Advances in water conservation are sharply decreasing per capita and per crop water needs. The recent state water plan illustrated how water conservation is one of the smartest investments. Installing a million low flow toilets in Los Angeles alone has restored critical water to Mono Lake. Time and again, investment in water conservation meets more water needs per dollar than dams.

By implementing strong meadow and forest protections, sound dam re-operation, better flood plain management and water conservation, we put into place a cost-effective, long term water supply plan that will bullet proof California from any water shortage – due to drought, climate change or other disaster. These solutions are not only great for water supply – but also water quality and ecosystem health. The Sierra to the Sea: Smart Path Water Solution is win-win for urban areas, agriculture, rural communities and wildlife!

For more information: Sierra Nevada Alliance, Joan Clayburgh, 530-542-4546, email: joan@sierranevadaalliance.org

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