UC San Diego biologists who examined the biological impact of replenishing eroded beaches with offshore sand found that such beach replenishment efforts could have long-term negative impacts on coastal ecosystems.
The scientists, who studied the effects of beach replenishment efforts on the abundance of intertidal invertebrates at eight different beaches in San Diego County, discovered that the movement of sand onto those beaches resulted in a more than twofold reduction in the abundance of intertidal invertebrates after 15 months.
“Such reductions may have far reaching consequences for sandy beach ecosystems,” the researchers warn in their paper, “as community declines can reduce prey availability for shorebirds and fish.”
Read the full article by clicking here.
The Quogue shoreline has been transformed since the October storm and the Jonas storm on January 23rd. These storms have decimated areas on the western end of the beach, in areas where a hopper dredge has been removing sand and transporting it to Fire Island since last spring.
The coincidence of these factors inspire a few questions. Among them…
- Why would a dredge remove sand so close to shore?
- Is it because it is cheaper and easier?
- Can these “borrow” sites replenish themselves in as short a period of time as some stipulate?
Conspicuously, the areas that have suffered the latest erosion are those westward of the dredge. The west end is now jagged, with cliffs ten feet high and severely eroded.
Ironically, the US Army Corps of Engineers’ own research has long recognized that “hot spot” erosion can be caused by offshore borrow sites that are poorly designed and located too close to the beach. Click here to access the report.
Decide for yourself if the unintended consequences of dredging seem worth the risk.
Above: A possible combination of nearshore dredging and storm tides during winter storm Jonas have cut away at Quogue’s western dunes and exposed old beach access stairways that had been buried for the last 30 years.
In 2012, Hurricane Sandy split Fire Island into two islands, creating a new inlet to the bay behind it. Contrary to the fears of many, there is no evidence suggesting that the opening of the new inlet has increased the risk of of flooding to the mainland (see the following USGS study, Hurricane Sandy Impacts Did Not Contribute to Subsequent Storm Flooding). In fact, scientists say that the breach actually helps clean the bay waters, and fishermen are seeing positive changes.
The following video is courtesy of National Geographic.