Fresh water

Here Comes the Sea: The Struggle to Keep the Ocean out of California’s Coastal Aquifers

photo: The Watsonville, California, recycled water facility, completed in 2009, purifies wastewater from the city of Watsonville for use by farmers in the Pajaro Valley. Using recycled water instead of groundwater prevents the Pacific Ocean from spoiling coastal aquifers with salt. Photo © Brett Walton / Circle of Blue

Farm districts preserve fresh groundwater with recycled wastewater

Driving on the world-famous Route 1, just south of town, a traveler looking west across fields of strawberries can see the great silvery expanse of the Pacific Ocean.

The land is heavy with a harvest that will soon be trucked to grocery stores and fruit stands throughout the United States. The Pacific, in the late afternoon sun, dazzles like camera flashes.

But the ocean also is stealthy. It creeps inland in less obvious, more destructive ways. Beneath the berry patch, a rising tide of salty water threatens one of the most lucrative and productive farm regions in the country. Coastal wells are slowly being poisoned with rising concentrations of chloride.

“Saltwater intrusion is the biggest untold water story in the world today. It’s a silent problem. It’s easy to ignore politically but it can spoil the water source for future generations.”
–Ron Duncan, interim general manager
Soquel Creek Water District

Saltwater intrusion, the technical name for the problem, occurs when too much groundwater is pumped from coastal aquifers, thereby upsetting the subterranean balance between inland freshwater and the relentless ocean.

Water moves through the ground as it does in rivers: from high elevation to low. At the margin of a coastal aquifer, fresh water and salt water mix. When the rate of groundwater pumping increases, the equilibrium shifts. As aquifer levels drop, the saltier water trickles in, filling the gaps in the sandy soil where fresh water used to be.

Saltwater intrusion challenges nearly every town and farm district in California that borders the Pacific. Many have been fighting back the ocean for generations. […]

Full article: Here Comes the Sea: The Struggle to Keep the Ocean out of California’s Coastal Aquifers