Southern California water supplies vulnerable to big earthquake

January 10, 2018
’94 Northridge earthquake breaks apart California infrastructure.

Since California—namely Southern California—is largely dependent on aqueducts and dams to transport water, earthquakes pose a significant danger to water supply. Jonathan Stewart, an associate professor and chair of the civil and environmental engineering department, recently presented his findings on the need to plan and build more resilient infrastructure especially for water systems at the public lecture program, “Distinctive Voices”, sponsored by the National Academies of Sciences, Engineering, and Medicine. According to Stewart, because California has so many fault lines that cross major water transportation lines, it is important to measure the resiliency, or recovery time, for functionality of existing water infrastructure following a natural disaster.

California relies largely on three aqueducts: the Los Angeles Aqueduct, the Colorado River Aqueduct, and the State Water Project. Each water source has differing levels of quality and risks to the transportation method—for example, the Los Angeles Aqueduct has excellent water quality, but it has a section with an underground tunnel (Elizabeth Tunnel) that is susceptible to earthquake damage. The State Water Project, which has decent water quality, also crosses fault lines a handful of times, making it vulnerable. The Colorado River has the lowest water quality and, unless mixed with higher-quality water, cannot solely be distributed on a large scale after a major earthquake due to its high salt content.

Scientists are working with policy makers to model various earthquake scenarios with the goal of avoiding a water supply shortage similar to that of the Hurricane Katrina aftermath. Mayor Garcetti commissioned a report on the resilience of the L.A. Aqueduct: Resilience by Design. The report offers 15 different options for addressing the risk to the Elizabeth Tunnel. One proposed option is to transition our supply to more local water sources such as reclaimed water and treating wastewater to secure a more self-sufficient water network that can have higher resiliency after large seismic events weaken water infrastructure.

Read more at Maven’s Notebook.

This post was written by Adrija Chakrabarty. She is a human biology and society major in her sophomore year at UCLA and a Special Assignment Assistant Content Writer for Sustainable LA Grand Challenge.