Droughts and Floods: How Climate Change is Affecting California’s Water Supply

January 27, 2017 | 11:25 am
Juliet Christian-Smith
Western States Regional Director

The beginning of the new year brought massive amounts of precipitation to the northern half of the Golden State. So much rain, in fact, that some rivers have flooded over their banks, damaging property and endangering lives. And today, the U.S. Drought Monitor estimates that only about 60% of the state remains in drought, with a very small portion of the state experiencing “extreme” drought conditions. Yet, a quarter of the state remains in “severe” drought, which includes some of our largest cities and dying forests. And year after year, we are using more water than we receive, causing long-term groundwater overdraft (we use about 1 million acre-feet more groundwater than is replaced, annually).

Thus, some areas of Southern California may continue to experience water shortages this year, particularly if warm weather melts much of the snow that has accumulated in the Sierras to-date. The risk is real given that scientists recently named 2016 as the hottest year on record (the third record-breaking year in a row). This spells trouble for snow.

Earlier this week, the Union of Concerned Scientists held an informational briefing at the Capitol to discuss how climate change is at the root of more extreme weather  – both floods and droughts. And scientists have been warning us about this for years.

Back to the Future

Back in 1988, Discover magazine ran a cover article on “The Greenhouse Effect.” The article examined how California’s water may be affected by climate change, featuring an image depicting more rain, less snow and flooding in the winter paired with hot, dry conditions and empty reservoirs in the summer. Sound familiar?

While snowpack levels look great right now, it’s simply too soon to say whether that snow will stick around through the spring to melt into reservoirs when water demands are the highest in the hotter months. Just last year, we had above-average snowpack at this time of the year. But a warm spring meant that the state’s crucial snowpack melted much faster than in the past, creating a false sense of security before running out. So although snowpack was near normal on April 1, 2016, only six weeks later it was down to just 35 percent of normal. And you know the rest, a hot summer brought continued drought stress and water shortages.

Our reality is changing. We can no longer rely on the type of infrastructure we currently have to deliver reliable water supplies. Global warming is changing our precipitation patterns and we need to change how we store, manage, and consume water if we are to have water security in the future.

It’s Time for Solutions

It’s not all bad news. There are solutions. First, California has been a leader when it comes to reducing heat-trapping emissions that create many of these problems in the first place. Secondly, our underground aquifers have about three times the storage capacity as all of our above-ground reservoirs. These underground reservoirs are located throughout the state and are a great place to put water that comes in the form of rain, rather than snow.

Groundwater is key to adapting to climate change in California since heavy rains can be captured underground and stored for use during drought periods. The only problem is that groundwater has been virtually unregulated in the state. That all changed a few years ago when California passed the Sustainable Groundwater Management Act, which is the first statewide requirement to manage our shared groundwater resources.

The Union of Concerned Scientists has been tracking the implementation of this law and is a part of the new Groundwater Collaborative webinar series all about how you can get involved in better local groundwater management (click here to find out more).  We hope you will join us.