barrier with 110,000 cubic yards of rock off West False River in Contra Costa County. Principal engineer Jacob McQuirk said that without the barrier, saltwater would endanger freshwater supplies in the Delta and water exports to the south.

“Every tidal cycle, that saltwater slowly propagates into the interior Delta,” he said. “Really, the beneficial uses of the interior Delta, they include agricultural supply, also interior municipal supplies.”

This is the second consecutive dry year for the state, with snowpack runoff being way less than expected.

McQuirk said 27 million people are dependent upon those water supplies and that the barrier will be taken down by November. However, if the drought continues into the following year, it may be reconstructed again.

“[If] it gets just too salty, we can’t export any water anymore,” McQuirk said. “Also, [it’s] not usable for those interior Delta municipalities.”