From the October 2013 issue of LAM:
By Adam Regn Arvidson, FASLA
Those lovely East Coast beaches with the fine white sand sloping into the ocean at a uniform distance from the hotels’ doorsteps are not at all natural. Nor are they stable. Every winter bulldozers or dredge boats visit the shoreline and dump more sand. In Virginia Beach, most of the sand comes from the constant dredging of Chesapeake Bay. Tourists are picky about the sand, and therefore so are the hotel, restaurant, and souvenir shop owners, but “beach nourishment,” as the sand-dumping practice is called, is expensive—and 65 percent of the cost is paid by the federal government.
The Dutch are experimenting with a different way of replenishing beaches, and an American landscape architecture professor is adapting those ideas to Virginia Beach.
Since 2006, Kristina Hill, now at the University of California, Berkeley, but until recently at the University of Virginia, has been working with a group of Dutch engineers to envision new ideas for the sea edge in New Orleans. Through that work she learned of the Sand Engine, a major project near The Hague where beach sand has been dumped in a completely different way. Instead of a uniform-width strand, the Dutch made a big triangle stretching out into the ocean. It has a little lagoon in the middle and a slight hook at the outermost tip.
“It’s huge,” says Hill. “And kind of amazing. People are using it in so many ways.” It has developed one of the better surfing point breaks in northern Europe and become a hot spot for kitesurfing. More birds feed and nest there than along other parts of the coast. And the nooks and crannies and slopes and pools in the sandspit provide a lot more variety. “You feel like a kid at the beach,” Hill says. “The Sand Engine creates an imaginative place that the straight coast does not have.” The Sand Engine evolves: As currents flow along the shoreline, they naturally redistribute the sand along the coast, and in the process change the shape of the original spit over time. The entire thing will eventually go away, but the Dutch think then they can just dump another big triangle in the same place and start all over again.
Conversely, Virginia Beach in 2000 built what is literally called the Big Beach. Faced with the need to reconstruct its seawall, the city opted for a low wall with a boardwalk on top and a very wide beach—originally 800 feet from boardwalk to shore, but with a minimum allowable width of 200 feet. Today it is between 500 and 600 feet (the hotels like 300 to 400 feet: wide enough but not too far a walk). Hill and a group of Virginia landscape architecture students proposed variations on the Dutch Sand Engine and showed them to Virginia Beach government officials and hotel owners. The study looked at two landforms—a triangle and a long skinny finger—and considered either one big deposit or several smaller ones. The study illustrates the change in the landforms over time. In general, the hotel owners were not thrilled, mainly because some hotels would have ideal beach widths, while others would be too wide.
But Hill insists this may be the way of the future, in part because of cost. The Sand Engine cost only 25 percent of what a typical beach nourishment project would, mainly because the installation costs are much lower. Adapting these Dutch techniques in the United States could possibly bring costs even lower, because the way beach nourishment is happening here now is more expensive than in the Netherlands. A technique called “rainbowing,” wherein sand is sprayed from boats onto the beach, is not allowed in the United States because the Army Corps of Engineers often requires a six-inch grade tolerance for sand placement, according to Hill. Placing sand by bulldozer is, of course, more expensive. And anyone who has ever visited a beach can recognize that those six-inch tolerances are probably erased within 24 hours of placement. The Sand Engine also has potential habitat benefits, according to the Virginia study. Because bulldozers aren’t on the strand every year, more animals, invertebrates, and plants can establish themselves in appropriate places. And those potential niches are more numerous with an evolving and, well, natural sandspit.
In Virginia Beach, there has been some push to build a pilot Sand Engine in Sandbridge, a community just to the south. Sandbridge is near state and federally managed conservation areas (which, incidentally, have sworn off beach nourishment) and also doesn’t have the political clout to get federally supported nourishment. Of course, the northerly currents will move the sand gradually to Virginia Beach anyway. And now that Hill is in the San Francisco Bay area, she hopes to try out the idea there. She thinks it is a critical time to be considering this alternative. “We’re headed for a tipping point,” she says, “over whether the federal government will provide funding for all these nourished beaches.” If the Sand Engine works, communities could pay for these themselves—far less frequently.