Dear EarthTalk: What are some steps we can all take to prevent beach erosion?
-- Kyle Phillips, via e-mail
Beach erosion is a huge issue for coastal areas in the U.S. and elsewhere. According to the non-profit American Shore & Beach Preservation Association (ASBPA), all beaches endure storms and other natural disturbances that cause them to lose sand, but the causes of beach erosion are not always the same. “On the West Coast, beaches are sand-starved when river dams block the flow of sand,” the group reports. That contrasts with Eastern beaches, they say, which often lack sand because inlets or navigation projects interrupt the movement of sand along the shore. “Things as disparate as storm-driven waves or a simple change in an offshore sandbar may cause one coastal area to lose sand while another gains.”
Concerted efforts to curb carbon emissions and
Credit: Soil Science at North Carolina State, courtesy Flickr
“Ultimately, a beach erodes because the supply of sand to the beach can not keep up with the loss of sand to the sea,” says Ken Rubin, Assistant Professor of Geology and Geophysics at the University of Hawaii. “Most sand is transported from inland via rivers and streams. The damming of most waterways in the U.S. has thus prevented a major supply of sand from getting to our beaches.”
He adds that beach erosion can be exaggerated during periods of rapid sea level rise, such as that which we are expected to experience soon as a result of global warming melting the polar ice caps. “When the encroaching sea comes against people’s property, the tendency is for people to try and stop the encroaching sea,” Rubin reports. “They armor the shoreline with seawalls, revetments, jetties, etc. [which] have a negative effect on beaches because once sea water reaches them, it ‘bounces’ off them with more energy than a wave washing back off a normal sand beach.” The result is that more sand is carried off shore, promoting additional beach loss. And the increased severity and frequency of storms due to climate change only serves to further stir up the remaining sand at many beaches.
Unfortunately, beyond keeping our carbon footprints in check, there isn’t much that individuals can do to prevent beach erosion. Building bulkheads in front of individual homes, or along entire beachfronts, may provide some short-term relief from beach erosion, but as often as not these actions can cause worse problems in the long run. And land use regulations that require homes and buildings to be built with a big buffer zone to the beach can go a long way toward protecting personal property and home values in coastal areas, but they won’t help prevent beach erosion.
According to ASBPA, physically adding sand to beaches to replace losses is really the best fix: “Coastal scientists have years of experience with beach restoration projects and have learned that adding sand in the right quantities, properly engineered and maintained, can make a beach last forever.”
Of course the best solution to any problem, including beach erosion, is to address the causes, not the symptoms. Concerted global efforts to curb the emissions that are driving climate change and the elimination of dams along inland waterways are both urgently needed lest we want to keep spending millions of dollars on remediation projects that just have to be repeated over and over again in what is essentially a losing battle.