Long-term problems require long-term perspectives. Those of us with a 10-year perspective may not be concerned about the existential threat of sea-level rise, but our children and grandchildren will have to deal with the consequences of our action or inaction. The ocean is warming, ice caps are melting and sea levels will continue to rise throughout the rest of this century (see Figure 1). The 0.9-foot increase forecast for 2030 may not seem like that much, but you should remember that translates into a 90-foot increase in beach run-up. If you walked along our beach this spring, you could see that the bases of sea walls were exposed north of 27th street, and the entire beach was much flatter at low tide than in previous years. The explanation from Scripps Institute of Oceanography (SIO) scientists is that high tides were bouncing off the sea walls and carrying away sand. Sea walls protect property but not the beach.
Del Mar did a detailed evaluation of the risks of sea level rise as part of the Sea-Level Rise Technical Advisory Committee study funded by the California Coastal Commission (CCC) in 2014-2016. This resulted in an Adaptation Plan, adopted in 2018, that specifically rejected the “managed retreat” option for private property.
The CCC review of the Adaptation Plan has been continued several times as CCC staff feedback has requested changes that the city has not agreed to. A final resolution may come at the June 9-11, 2021 CCC meeting.
A first priority in the yet-to-be-certified Adaptation Plan is beach sand replenishment. That may help as a stopgap measure, but winter storm surges will move the sand southward and it will end up in the offshore La Jolla Canyon just south of the SIO pier. Each spring, more sand will need to be replaced and the cost will escalate. For example, the Army Corp of Engineers is directing a 50-year sand replenishment project in Encinitas and Solana Beach at a projected cost of $167 million dollars (in 2016 equivalent $). This project is just to protect limited stretches of beach at Moonlight Beach and Fletcher Cove, not the entire beach in each city. The hidden benefit is that sand will move south each winter and Del Mar could share the temporary benefit. That may help until 2030, but what about long-term plans?
2050 may seem like a long way away, but serious planning for sea-level rise needs to consider the time to develop, fund and execute major infrastructure projects. The current plans to relocate the train tracks off the Del Mar bluffs offer a timely example. Initial planning began over a decade ago, and it has only recently accelerated as bluff failures have come closer and closer to the tracks. Only early design work is funded, and the start of construction looks to be a decade away at a projected cost of over $3 billion, a number sure to increase. The highway and rail bridges over the San Dieguito River need to be raised from 4-8 feet, and neither project is fully funded for construction. The fire station, the 21st Street pump station, and the public works building are in the flood plain and need to be relocated. So when will we begin to take these challenges seriously? It is time to stop kicking the can down the road and start making the necessary decisions to protect our coast and not to saddle our children and grandchildren with disaster-driven, mega-expensive fixes. While we wait for these longer-term solutions to become reality, maybe local property owners can invest in improvements (like raising the floor level of habitable space) that will provide resiliency to the oncoming waves.