The rain that fell on California in recent weeks could have supplied the state’s water needs for 10 years — if it had been captured and stored. Unfortunately, most of the water is being left to drain to the Pacific Ocean.
California received some 32 trillion gallons of water in three weeks of “atmospheric river” storms across the state, according to Fox News. In 2014, the state used 42 million acre feet, or about 1.4 trillion gallons, annually, according to the Desert Sun, citing the U.S. Geological Survey (USGS). (A more recent figure from USGS suggests the state withdraws up to 28,800 gallons per day, or about 1 trillion per year, from the environment.)
Given that the state only taps half of its water supply for human uses, about 16 trillion gallons of the rain that fell on California in the last few weeks could theoretically be directed to human use — if it were stored. That means that enough rain fell to supply the state’s water needs for at least another decade — and maybe longer.
However, the state’s water storage capacity is only 43 million acre feet, matching about one year’s human use. Given that most reservoirs — even in the ongoing extreme drought — have some water in them, not all of the 43 million acre feet of storage space is available to capture the ongoing rains — and some dams’ floodgates have been opened. More than 95% of the rain that is falling on the state is simply being allowed to wash out to sea.
Gov. Gavin Newsom (D) is hosting President Joe Biden on Thursday to survey recent flood damage. Newsom has proposed spending some federal infrastructure funds on reservoirs. Yet the state’s voters already approved nearly $3 billion in 2014 for water storage projects, and no new reservoirs have been built in the decade since.