Earlier this month the U.S. Fish and Wildlife Service completed a $1.65 million restoration project of five beaches in Cape May County, New Jersey, that had been affected by Hurricane Sandy in 2012. This beach restoration project is just one of many going on in the Northeast and throughout the country to help repair and replenish beaches that were either damaged during that destructive storm or have suffered in other ways over the past few years.

Beach restoration, also known as beach nourishment, is an expensive and time-consuming process, but it has also become essential now that so many communities depend on beaches not just for recreation but also for protection from the ravages of ocean-bound storms. But it's not just storms; according to the American Shore & Beach Preservation Association, most of the popular beaches in the U.S. have undergone some form of nourishment over the years to reverse the effects of natural erosion.

Of course, beach erosion is a perfectly normal situation, says Nate Woiwode, policy advisor for The Nature Conservancy of Long Island. "Over time, these beaches are moving," he says. "The sand that's on a beach today is not going to be the sand that's on the beach next year." Waves and winds move the sands from a beach up and down over time, and Woiwode points out that no beach is a static system. "The challenge," he says, "is when you take the natural system and put in human-build infrastructure." The addition of homes, roads, seawalls and other structures places permanent objects into a dynamic system. It can also inspire the need for humans to take action and "fix" beaches that have become damaged by natural systems. "When you put the houses and roads behind a beach and that beach starts getting smaller, that can inspire the decision to start to nourish the beach and build it back out," he says.

Beach restoration can take a lot of forms, and it's a fairly complicated process with a lot of science behind it, says Tim Kana, president of Coastal Science & Engineering, who has been working on coastal erosion projects for more than 30 years. "We focus very much on the variations from place to place," he says. "Just because one beach does something doesn't mean Myrtle Beach is going to behave the same way." Each project considers a region's tidal strength, the sand supply available naturally in the system, structures such as sand dunes and barrier islands, and how a beach varies throughout the year.

Beach nourishment projects vary, then, based on the nature of beaches and the communities that surround them. Some projects require trucking in thousands pounds of sand to replace what has been lost, either at the waterline or to build or rebuild dunes. Other projects might build seawalls or breakwaters or other structures to further protect shorelines. The goal, the experts say, is less about appearance than it is to enhance habitat for species and, most importantly, improve beaches' natural ability to provide communities with a defense against storm systems.

Along the way, choices need to be made, but they may not really be choices. "We're either going to have to bring in more sand or settle for a smaller dune or move our houses back," says Kana. The latter isn't really an option. Fortunately, Kana says, most developed beaches already have the natural barriers that keep their fairly stable. "The annual rate of change is measured at three feet or less per year," he says. Developed shorelines need to decide if they can live with that three feet of change or if they want to "manage it proactively with nourishment." The first choice is usually trucking in sand – "you want to look at how much sand it will take just to hold the line," he says.

But is holding the line enough? Woiwode points out that dunes — which may naturally disappear and reappear over time — helped to limit the amount of flooding that impacted some areas during Hurricane Sandy. "But dunes are part of this ephemeral nature of the system," he says. "They don't provide permanent protection because they move." If a hurricane such as Sandy eliminates a dune, communities may decide they need to recreate it sooner rather than wait for it to maybe reappear to protect them from future events.

That's challenging, though, and Woiwode says it leaves out part of the equation. He points out that relying on piles of sand to function as natural dunes "doesn't provide much habitat value" for seabirds and other wildlife, which are also essential parts of the natural system. "You have to take a holistic view to make sure that everything is functioning naturally," he says.

Beaches may be natural systems and important ecosystems, but they have also become thriving human environments. "If you think of the economy of the Jersey shore, that is a tourism-driven economy," Woiwode says. "If there is no beach there, that economy is going to go away. It isn't just a question of is there a place for birds to land. It really starts getting into the fundamental nature of what these beach communities are, how their economies are structured, and what they're going to do in the face of rising seas and potentially limited sand as their beaches erode." Those questions will undoubtedly inform beach restoration projects for decades to come.

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