Rising sea levels threaten California's water supply

Without a coordinated response from public agencies and the private sector, California's economy will be significantly impacted by the rising sea levels that stem from global warming. That's the big picture that emerged from a recent hearing in Half Moon Bay hosted by Assemblyman Richard Gordon, D-Menlo Park, and the Assembly Select Committee on Sea Level Rise and the California Economy.

Scientists and industry leaders testified about the hazards faced by coastal agriculture, fishing and tourism industries. Much of the testimony highlighted threats that don't typically receive a lot of attention.

For instance, as much as 48 percent of California's water supply comes from groundwater that could be contaminated by saltwater as sea levels rise, geologist Mary Scruggs of the state Department of Water Resources warned. Once such contamination occurs, Scruggs noted that it's hard to fix.

“By the time saline water enters the groundwater, you've got a big problem, and you've lost that aquifer,” she said.

Possible responses could include reducing or halting the pumping of water from coastal wells so saltwater doesn't contaminate nearby aquifers. And some wells that aren't used as water sources could simply be filled with water to act as barriers between fresh water sources and the saltwater that threatens them, Scruggs said.

After all, many crops can only be irrigated with fresh water, and are damaged by salt.

Monterey County Farm Bureau Executive Director Norm Groot noted that his county has 22,000 acres of farmland in the coastal zone, mostly at sea level. Salt levels in the soil are already rising, he warned, and seawater is intruding 10 miles inland, encroaching upon the Salinas Valley. That could affect the area's wine corridor, he said, as well as restricting the other types of crops that can be grown.

But rising carbon emissions also will affect the sea itself. As the ocean absorbs more carbon it becomes more acidic, hurting the ability of shellfish such as oysters and sea urchins to grow shells.

“We stand to lose our coastal ecosystem and our cultural identity,” said marine biologist Gretchen Hofmann.

Zeke Grader of the Pacific Coast Federation of Fishermen's Associations said commercial fishing would be one of the industries hit hardest, because all of its ports, processing plants, and other facilities are in harm's way.

“Everything's on piers,” Grader said.

Gordon will host another hearing in Long Beach in the fall. That hearing will examine the effects of sea level rise on California's shipping ports, infrastructure and airports.

When asked what he would say to those who still believe climate change isn't real, Gordon said, “I understand there are folks that don't believe we have global warming. My response to them is that whether you believe or not, we have scientific data which shows that the sea is rising.”

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