The erosion of beaches in Marina finally has a fighting chance to end.

With all the disaster this past winter has wrought, there is a silver lining beyond the recharge to the region’s aquifers: beach replenishment.

Sand on the beaches, locally, comes from the land, and it arrives there in one of two ways: erosion from existing dunes or rock formations or through the waves, with sand that is carried from the outflow where a river meets sea.

In the case of the Salinas River, this is shaping up to be a historic year for such replenishment, in large part because of the cessation, at the end of 2020, of the Cemex sand mine in Marina, which captured much of the sand that was traveling south down the coast from the river mouth, which is only opened up by the county in heavy rain years like this one.

(The steam still coming out of the Cemex plant is because the company has until the end of 2023 to process and offload its stockpiled sand, per a consent order from the California Coastal Commission.)

Local coastal engineer Ed Thornton, now retired, was the leading voice that helped shut down the sand mines, which until the late 1980s stretched from Sand City to Marina.

The problem they created was one of erosion: You take sand out of the system and the coast will retreat, a problem that will be worsened by climate change-induced sea level rise.

But the difference in the beaches in Marina won’t be noticeable in how it looks – it will just prevent the beach from retreating. “You only see erosion when you have a building perched on the cliff,” Thornton says.

The hope, he says, is that now, with the cessation of local sand mining, the natural replenishment will prevent further erosion in the face of sea level rise.

“They’re in competition,” Thornton says. “I would hope it would keep up with sea level rise, so what we see is a net-zero, so the whole shoreline becomes stable.”

This winter, he says, was “a big year” to that end.