STATE OF THE WATER: An in-depth look at how the 2023 wet season has affected LA County’s water supply

This blog is the second of a four-part series. You can read part one here.

Part 2: The Storms & the Aftermath 

California’s winter weather has been a topic on repeat this year, with nonstop coverage dissecting the status of our drought, record snowpack, and nearly full reservoirs. 

Since October 1, the start of the wet season, Los Angeles has received more than 24 inches of rain, which is nearly 200% of normal for the time period. This deluge of rain comes on the heels of a three-year megadrought, one which intensified the state’s water deficit and triggered dire water shortages as unfavorable precipitation trends and intense heat waves persisted across the state.  

At the start of the year, LA County was under strict water restrictions. A record dry 2022 prompted California water officials to reduce the State Water Project’s expected deliveries to just 5% of full allocations. What’s more, nearly 4 million Angelenos receiving water from the Los Angeles Department of Water and Power were under additional regulations limiting outdoor watering for more than 6 months. 

Then came the storms. 

How the string of Atmospheric Rivers impacted Communities 

Just as weather forecasters cannot predict the length or intensity of a drought, it is difficult to forecast the strength and duration of a rainy season. This season, the rainfall broke a 130-year-old record for daily rainfall in downtown L.A; with other locations  across the state receiving their annual average rainfall totals in less than one month. 

The effects of the 12+ atmospheric rivers that hit California have caused more than $5 billion in damage in the state, with the threat of further damage from widespread flooding looming as the Sierra Nevada snowpack begins to melt.  In the Los Angeles Basin, almost half a million people live in areas at high risk of flooding, with more than $50 billion worth of property exposed even in a modest flood. As a result of climate change, the risk of a devastating megaflood has more than doubled in California. 

Whatsmore, this year’s deluge of rain has proved that LA’s current water management system is outdated. As climate change brings drier dries and wetter wets, our water infrastructure and policy needs to adapt to this “new normal.” We need to optimize water capture and storage during the wet season, balance water recycling, and keeping minimum flows in the LA River and other inland waterways to support habitat restoration during the dry season to build up our water resiliency in the face of these extreme weather patterns. 

A study conducted by the University of California, Irvine and Boise State University in 2018 captured this trend of intense weather patterns, concluding that as the climate changes, the streamflow is projected to increase during most of the rainy season (December to March). And, it is expected to decrease in the rest of the year (i.e., wetter rainy seasons, and drier dry seasons). Knowing that we will be hit by these increasingly intense weather patterns, we need to prepare for it. While the LA region is making strides in this direction, in a county that still relies heavily on imported water, more can and must be done to optimize these periods of heavy rainfall and bolster our water supplies in LA County, or we will contine to miss out on the valuable resource. 

Next Up 

In our next blog, we are going to look at the state of LA county’s water supply as of the end of the 2023 wet season. We will look at the state of our local water reservoirs, our groundwater supply, and how much of this water was actually captured with our current water infrastructure.