New research is shedding light on how mechanically placed sand on San Diego County beaches moves and its potential impacts. The study, published in the journal Coastal Engineering, could help planners develop beach nourishment projects that will reach their intended goals without causing unintended problems. North San Diego County for instance is planning a 50-year, $160 million series of beach nourishments intended to combat flooding and erosion, and provide recreational space for tourists.
New research is shedding light on how mechanically placed sand on San Diego County beaches moves and its potential impacts. The study, published in the journal Coastal Engineering, could help planners develop beach nourishment projects that will reach their intended goals without causing unintended problems. North San Diego County for instance is planning a 50-year, $160 million series of beach nourishments intended to combat flooding and erosion, and provide recreational space for tourists.
The new study, conducted by researchers at the Scripps Institution of Oceanography at the University of California, San Diego, and funded in part by California Sea Grant, analyzed four beach nourishment projects in San Diego County to see how they fared in the years after the nourishment. It provides a better understanding of how nourishment sand moves in response to waves and currents, which could provide insight for more effective beach nourishment projects in the future.
“There’s a lot that is not known about how sand moves,” says Scripps postdoc Bonnie Ludka, who led the study. “If you put sand on a beach, it won’t just stay in one place. The question is, how long does it stay where you want it? And as it moves, where does it go?”
For example, sand placed on Torrey Pines beach north of San Diego in 2001 washed away in a single storm. Nourishment sand can also lead to other unintended consequences, as happened at Imperial Beach, the site of the largest beach nourishment in the study. There, 138 Olympic sized swimming pools worth of sand were added to the beach in autumn of 2012. The sand moved both north and south along the coast, and in 2016 contributed to the closure of the Tijuana River estuary. The river lost its connection to the ocean, leading to extremely concentrated pollution and hypoxia—loss of oxygen in the water that can cause die-offs of fish and other aquatic species.
Read more at University of California - San Diego
Image: This is Torrey Pines beach north of San Diego, fall 2017. Sand placed on the beach in 2001 washed away in a single storm. (Credit: Katherine Leitzell | California sea Grant)
