Inexpensive fences help restore sand dunes.
By Wendee Holtcamp
Biologists on the upper Texas coast have found a simple, and economical, solution to a rapidly eroding shoreline: plant a fence, and it will come. Sand, that is.
“Texas Point National Wildlife Refuge has some of the most extreme erosion — possibly in the U.S. — where 50 feet of shoreline is being lost each year,” explains Marty Bray, until recently the refuge manager at McFaddin NWR, which is also losing 8-12 feet per year. So much beach had eroded that the clay underneath became exposed, turning what once were natural beaches into cliff-like banks. McFaddin is a few miles down from Texas Point; both lie within the Chenier Plain geological formation — coastal swales formed from sediment coming down the Mississippi River and spread out by currents along the coast.
“Most people are in agreement that the area is sediment-starved due to dams preventing sediment from flowing down rivers that historically replenished shoreline,” explains Bray. Because of miles of jetties, sediment that does make it downriver ends up further offshore in the continental shelf rather than at the river’s mouth, where currents would otherwise distribute it along coastal beaches.
“In a natural system the dunes will get eroded during storms but build back during the spring and early summer,” explains Dean Bossert, the current refuge manager. “In the system we have now, they don’t build back because there is a lack of sand in the system.”
While the Army Corps of Engineers was spending thousands of dollars studying whether massive textile “geotubes” could prevent erosion, Bray, Bossert and refuge biologist Patrick Walther had a simpler idea. Walther’s sister had installed sand fences along the Louisiana coast to rebuild dunes, so they brought the idea to Texas. Using relatively inexpensive supplies, they installed a few miles of fence, planting Atlantic panicum grass to help hold sand and rebuild the dune. Within a few months, several feet had accumulated.
Dunes not only create a more aesthetically pleasing beach and provide habitat for beach critters, they also buffer the impacts of storm damage, protecting human life and prop-erty. At Louisiana’s Holly Beach, just a few miles from where the eye of Hurricane Rita hit, several miles of beach and recreated dunes had been replenished using sand fencing, which prevented further damage. “That beach has a highway — Louisiana Highway 82 — sitting just 200 feet from the Gulf of Mexico and the road was barely damaged,” says Walther.
Although Rita destroyed the fences at McFaddin NWR, the new dunes survived. “Much of the foredune was washed away, but the back dunes were protected,” explains Bossert. Unfortunately in much of their 18-mile coastline, the erosion rate occurs too fast for the sand fences to be effective. More sand is needed to re-establish dunes, but funding is currently hard to come by. Other places along the coast could benefit from this inexpensive method of dune restoration, says Walther. “Places like Bolivar Island and Galveston have a lot of potential to benefit from sand fencing.”