SOLANA BEACH — Thanks to two sand replenishment projects city beaches are wider now than they were about 20 years ago.
That’s the good news.
Without similar future projects, however, that increase could be washed away, according to a report at the June 25 council meeting from Greg Hearon of Coastal Frontiers, a coastal engineering firm.
Hearon likened the situation to a bank account.
“If you’re putting in more than you’re getting out, your balance grows,” he said. “Or in this case, your beach widths gain. Your sand volume increases.
“But if you’re not putting in as much, more is leaving,” he added. “You’re going to have an erosional type situation. So that’s essentially where we are. We’re not putting as much on the beaches as we had in the past so we can expect that the long-term trend probably is going to be erosional.”
The San Diego Association of Governments conducted regional beach replenishment projects in 2001 and 2012. In the overall project area, from Oceanside to La Jolla, less sand was dredged from borrow sites in 2012.
But Solana Beach received about 142,000 cubic yards of sand both times.
Solana Beach established a monitoring program in 2002 that is designed to document changes in the shore zone, evaluate the impacts of human intervention and natural events such as El Niño and develop a foundation for future sand nourishment projects.
According to measurements from the program there was an initial loss of sand during the first year but not so much that the net outcome wasn’t positive, Hearon said.
Sand from the second project seems to be staying on the beaches longer, primarily because the grains used were much coarser, he added.
Along the entire coastline of Solana Beach there has been an average beach width gain of about 36 feet, Hearon said.
At Fletcher Cove, the beach is now about 90 feet wider than it was before the first replenishment project, when it measured about 104-feet wide.
It increased to 132 feet after the first nourishment and 193 feet following the second project.
“It’s really nice to see that the projects seem to be maintaining wider beaches for you,” he said.
Hearon also noted that while it appears the sand has been moving south, it is staying in Solana Beach. He said the monitoring efforts didn’t indicate much sand is moving to beaches in Del Mar.
“Most of that material stayed in Solana Beach for the first year,” he said.