Wouldn’t the water taken out of the ground just create a vacuum to pull more seawater in?
No, a trough would be created to serve as a seawater barrier underground. Water supply wells placed in two parallel rows, one row right behind the sand dunes and one row a mile inland, would draw down water pulled around the well. The coastal side of the well pulls ocean water more heavily through the 180 foot deep aquifer, and the inland side would pull seawater intruded groundwater toward the well. Over time the groundwater on the inland side of the wells would be restored to pristine quality by the removal of salts from the desalination process. Salinas River diversions will also work to block the entrance of the seawater into the aquifer by offsetting groundwater use with surface water use, leaving more fresh water in the ground to flow toward the ocean.
