Climate change threatens EBMUD water resources

Most of California's precipitation falls in Northern California during the winter, while the greatest demand for water comes from users in Southern California during the spring and summer. An intricate network of reservoirs and aqueducts carries water throughout California from rivers starting in the Sierra Nevada, and from the Colorado River. The current distribution system depends on the Sierra snowpack to store water during the winter, gradually melting in the dry spring and summer. An increase in temperature could reduce the snowpack by as much as 80%, causing major disruption to our water system.

Without major action to stop global warming, more precipitation will fall as rain instead of snow, and the snow remaining will melt earlier. California will lose its largest natural reservoir; global warming will put pressure on our water system.

In the last 50 years water temperatures have risen by 2 - 3º F. As this trend continues, it will put pressure on restoring the fish runs along the lower Mokelumne River, where EBMUD and the Department of Fish and Game operate a hatchery that is restoring salmon and steelhead trout. The fish need cool water to spawn, which is currently achieved by using artificial shade. Global warming will reduce the time period when the fish can spawn.

As a result of earlier spring runoff, the warm-season share of annual stream flow has declined. In the last 80 years April-July flows on the Mokelumne have declined from 70% of the year's flow to less than 60%. This water, instead of staying frozen as snow, is flooding down the river, where there is not currently enough capacity at Camanche Reservoir in a climate-change scenario. Preliminary projections show flows down the river of 15,000 cubic feet per second (cfs), while the river capacity is only 5,000 cfs. These flood episodes will impact communities and ecosystems. Conversely, springs and summers will be dryer, increasing the importance of water conservation and of securing cost-effective and environmentally sensitive mitigations such as groundwater storage and flood-control infrastructure in upcountry areas.

Lastly, a major sea-level rise could interrupt performance of EBMUD's wastewater treatment plant, and intrude higher salinity levels into the Delta, where there is great need to maintain adequate river flows to protect the delicate ecosystem. The Mokelumne aqueducts also cross the Delta, and the rising water would cause them increased corrosion.

Efforts to stop climate change, such as better market-pricing of energy and carbon-emissions reductions, may come with a price, but we need to understand that the damage to our environment has a price, as well as the actual cost to our public infrastructure. EBMUD is cutting emissions by installing solar panels at many of our worksites, using hybrid vehicles, and capturing methane gas from the wastewater treatment facility to supply energy. Please do your part to conserve energy and support state regulatory efforts and federal legislation to stop global warming.

Andy Katz, EBMUD director, representing Albany, Berkeley, El Cerrito, Emeryville, Kensington, and North Oakland