California has water issues. As a state, CA currently does not have enough water to meet all of our personal, agricultural, industrial, and recreational needs. We already import water from the Colorado River, and we have already drawn down our existing reservoirs in our underground aquifers to meet these needs. Probably none of this background comes as much of a surprise? Our water woes have been well-documented and publicized for decades, dating back to the days of Mulholland. The question is, what are we doing about it--and what does the future hold?
As I mentioned before, climate change has made predicting the future much more difficult. It used to be that historical models could be counted on to accurately predict what would happen in the future. Water planners have been able to rely on the concept of "stationarity": that you can use historical water flows to plan for future water availability. Sure, there have always been unusual events that happen once every 50 or 100 years, but our weather operated in a known range. This is no longer true. "Once in a lifetime" events now happen every 10 or 20 years. New and previously unforeseen events are occurring. We're in new territory, and although we have no crystal balls, we do have computer modeling. It allows us to make reasonable decisions on what might happen, and what is most likely to happen.
For example, the Department of Water Resources is expecting the water CA gets from the annual Sierra snowmelt to decrease by 25-40% in the next 50 years. Considering that this natural resource is an important source of water for CA in the late spring and summer months, DWR must decide not only how to replace this water supply, but also whether resources can/should be dedicated to capturing and retaining precipitation that may fall as rain (and quickly runs off) rather than slow-melting snow?
Further, what about sea-level rise? Sea levels have already risen over a foot in the last 50 years. They are expected to rise another foot by 2050. However, remember that slow but profound effect I mentioned before in the last post? Sea levels are projected to rise approximately 55 inches between 2050-2100! Imagine what this will do to low-lying areas such as Venice, Florida, New Orleans--and the Sacramento River delta. Literally thousands of acres of productive farmland could be inundated, and our existing levee system is currently not ready for sea-level rise of such magnitude. Further, salt water will encrouch up river many miles further inland, affecting fresh-water availability.
There are a few easy answers. For example, golf courses use (on average) over 300,000 gallons of fresh water a day. (Is the economic and/or recreational value of a golf course worth this cost in water resources?) We currently do very little with water recycling, and many of our reservoirs, pipelines, and other delivery systems are porous, leaky, or otherwise inefficient. We have made progress with low-flow shower heads and more efficient toilets. Much can still be done to improve our water infrastructure.
Unfortunately, although these answers will help, they will not begin to solve our water problems--especially for a state with a huge agricultural industry, and a population that is expected to increase another 10 million people by 2050. The good news, if there is good news, is that DWR is no longer using modeling based on historical averages, or wishful thinking. They're using the modern computer models to base their planning on the best science available, not history or hope. They have a hard task ahead, and unfortunately things may well get worse before they get better on this front. In the meantime--don't flush that toilet!
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