Bulkheads: Bad News for Shoreline Protection?
by Steve Williams, P.E., on January 24, 2020
Average water levels are on the rise around our nation's coasts and waterways which have people scrambling to find efficient protection methods to save our eroding shorelines. However, some of these erosion methods may actually cause more harm than good.
Bulkheads, vertical structures installed parallel to the water, have been used to protect valuable land from being eaten away by harsh wave energy. However, studies have shown that bulkheads may actually encourage erosion because they simply deflect the wave energy to other areas along the shoreline. Nearby areas without coastal protection suffer instead.
What about coastal protection from major storm events? When it comes to a hurricane and storm surge, isn't a solid bulkhead the way to go? Actually, they may offer less protection than you think. This article from Scientific American details how a majority of the bulk heads installed in the Outer Banks of North Carolina suffered damage by Hurricane Irene while the natural marsh shorelines were not impaired. If something that appears solid and strong like a bulkhead can't protect our coasts, then what's the answer?
Creating structures that absorb wave energy has shown to be the better approach. Armor stone revetments placed out into the waterway work to dampen the wave energy. This video, captured by the USACE Buffalo District, offers an excellent side-by-side comparison of a coastal bulkhead and an armor stone revetment. You'll see that the revetment dissipates the wave energy before it reaches the shoreline unlike the bulkhead.
Better Shoreline Protection for Coasts and Waterways
As climate change and subsidence begin to endanger America’s coastal communities, city and state governments are struggling to stand their ground as it literally sinks below them. We invite you to watch our on-demand webinar: "Geosynthetics for Coastal Protection Applications." Here, we discuss various solutions for coastal erosion and compare their pros and cons. You'll also be eligible for 1 PDH credit for your time.