In 2018, South Carolina pumped 40,000 cubic yards of river sand onto an eroding bird island; enough to fill about 4,000 dump trucks and restore lost nesting ground

A 35-acre island between Folly Beach and Kiawah Island is off-limits to people, but it's become essential real estate for thousands of nesting birds. This is Bird Key Stono, and in 2018 it received what can only be described as an unglamorous facelift: 40,000 cubic yards of river sand, dredged from the water and dumped onto its shrunken shoreline.

It's easy to overlook a story about sand, dredging, and government contracts, but if you stand back and take the long view, a 2019 study titled “Decline of the North American Avifauna,” in the journal Science, takes on new meaning. It found that the continent's bird populations had fallen by a net 2.9 billion individuals since 1970, a roughly 29% drop in total abundance across all species combined. With that in mind, an island receiving a sand treatment doesn't seem so unimportant.

When a hurricane moved out


Bird Key Stono is no ordinary sandbar; it's an official critical habitat for the piping plover, a threatened and endangered bird species, and is jointly protected by the State of South Carolina, the South Carolina Department of Natural Resources, and the U.S. Fish and Wildlife Service. The U.S. Army Corps of Engineers' Charleston District reported that Hurricane Irma caused so much erosion along the island that nesting birds barely had enough space to survive before the spring nesting season began.

The solution was far from elegant: a cutterhead dredge named Cherokee excavated sand and water from the floor of the neighboring Folly River, which was then funneled through pipes and spread along the island's shores, where it was shoveled into usable land by bulldozers. The entire venture, which took the form of 4,000 dump truck loads of material, cost $300,000 and was entirely federally funded, done specifically so that birds would have suitable nesting grounds when the time came.

Why a sandbar's integrity matters more than it seems

What many people don't realize is that barrier islands like Bird Key Stono are incredibly unstable ecosystems, made even more unstable by rising sea levels brought on by climate change. According to a 2011 study titled “Effect of sea-level rise on piping plover (Charadrius melodus) breeding habitat,” published in the journal Biological Conservation, piping plover habitat modeling on New York's barrier islands showed that a rise in sea levels could cause nesting grounds to shrink by an astonishing degree, unless those habitats were able to migrate inland.

That migration, however, can be impeded by human development, which the model showed could reduce the available habitat by up to 12%. In fact, the study also showed that a single major hurricane could cause up to 95% of plover habitat to become temporarily flooded. These figures come specifically from New York's micro-tidal barrier islands, and they don't transfer cleanly to South Carolina's Stono Inlet; the wave energy, tidal range, and sediment dynamics of a sub-tropical estuarine coastline are quite different from the mid-Atlantic. Still, the underlying pressure is the same one playing out at Bird Key Stono: these birds are fighting a losing battle against rising tides, and their survival depends on being able to move and adapt.

Sand meets science

The real-world implications of the Bird Key Stono story tie directly into this idea of natural habitats being encroached upon by development. NOAA's National Centers for Coastal Ocean Science has partnered with the Army Corps' "Engineering With Nature" program on a set of case studies, including Mordecai Island in New Jersey and Swan Island in Chesapeake Bay, documenting how dredged sediment has been used to rebuild eroding islands, with the stated aims of reducing storm-surge risk for coastal communities while also restoring wildlife habitat.

It's a compelling argument, and the fact that dredging material otherwise destined for disposal sites gets repurposed into new habitat is, by most measures, an efficient use of a byproduct that already has to go somewhere. After all, why buy new material to build up the land when you can use dredged sand to both clear the waterways and build new islands at the same time? That efficiency is worth acknowledging, and it doesn't take away from the result: a once-threatened bird sanctuary now has the nesting grounds it needs to thrive. In a country that's seen massive declines in its avian populations since 1970, a few thousand dump truck loads of sand pumped into the heart of a protected shoreline is an investment that pays off in conservation dividends, one eroding sandbar at a time.