Coast to Coast

Nov. 1, 2004
Those of us who live in coastal areas-and according to the National Oceanic and Atmospheric Administration, more than half of us in the continental United States do-have particular reason to watch what’s happening to the shorelines. As more people and more activities crowd toward the water, even slight changes to coastal sands, cliffs, and bluffs have major economic and environmental effects.Large storms like those that hit the Southeast during this year’s hurricane season can cause dramatic changes in a very short time and make us appreciate all over again the tenuous line between land and sea. Most coastal erosion, however, is slower but incessant. Louisiana in the best of times is losing about 25 square miles of coastal wetlands every year. In other areas the total amount of erosion is less but threatens expensive development and beaches that attract tourism.Just as all causes of coastal erosion are not the same-some is gradual, brought about by wave action over time; some is caused by hurricanes and other storms; some is caused or accelerated by human activity-the reasons for remedying it differ as well. Many of us in the erosion control industry are working for different causes, sometimes even at cross purposes. As Gary Griggs, director of the Institute of Marine Sciences at the University of California, Santa Cruz, has pointed out, beach erosion and shoreline erosion are different things; the sea wall that protects the buildings behind it does nothing to save the sandy beach in front. It’s all a matter of what we want to save most. Similarly, the steps we must take to protect offshore reefs and littoral habitats might be very different from those to ensure the safety of seaside real estate developments.In developed areas, where manmade structures may have already changed the dynamics of waves and sand, the first goal is usually to protect the economic investment. Measures like sea walls, jetties, groins, and other engineered structures to protect a particular piece of land are often accused of altering wave energy or movement of sand along the coast and making the problem worse for neighboring areas. The need builds on itself: more development, more people, more investments to protect. Some 12% of California’s more than 1,300 miles of coastline is now armored with sea walls and concrete.Since it’s unlikely that those of us living in the one-fifth of the land closest to the oceans will migrate en masse to the central plains, finding a way to balance the needs of development with those of the environment is more urgent than ever, and it falls squarely in the domain of the erosion control industry. The article in this issue on streambank stabilization describes a three-year project to compile information on different methods for restoring eroding streambanks, particularly alternatives to the hard-armor (riprap and concrete) standbys that many engineers turn to by default, and to distribute that information as widely as possible. Similar efforts for coastal mitigation techniques-not only what erosion control measures are working and under what conditions, but also how different states are formulating or changing land-use policies to discourage unsound beachfront development-would be a welcome addition to the field. As state governments, FEMA, and private insurers pay out billions in the aftermath of this year’s storms, perhaps some of them will find it to their advantage to help fund this type of research.