PEP Members Spearhead Solutions to Shoreline Erosion
Communities throughout the Gulf Coast face difficult decisions in how to best manage and adapt to shoreline erosion. Man-made disturbances, rising sea levels, and larger, more power storms have resulted in severe shoreline erosion over the past several decades. Partners for Environmental Progress member organizations are stepping up to tackle these issues by protecting, enhancing, and restoring coastal habitats, the state’s greatest economic and environmental asset.
Alabama’s white sand beaches and coastal dunes are naturally dynamic. The ever-changing shoreline is shaped by fluctuations in sea level, wave action, Gulf currents, prevailing winds, storms, erosion, and deposition. This results in a diversity of habitats that defend against storm surge and flooding, provide critical habitat for fish, crabs, and oysters, and serve as havens for migratory birds and other wildlife.
Man-made environments, on the other hand, are static. Buildings and infrastructure are largely incompatible with the natural movement of coastlines and dunes. Historic attempts to tame and stabilize shorelines, along with other human disturbances, have negatively impacted the resiliency of coastal habitats and their ability to rebound from hurricanes, flooding, and erosion. Destruction of coastal habitats leaves man-made environments more vulnerable to natural disasters and negatively impacts local fisheries.
Working in Harmony with Nature
According to Scott Douglass, P.h.D., professor emeritus at the University of Southa Alabama’s Department of Civil, Coastal and Environmental Engineering, beach erosion is a natural phenomenon. ‘All barrier islands move,’ he says, ‘Beaches move. Beach erosion becomes a problem, through, when you have property lines and buildings and infrastructure. In modern history, a lot of beach erosion wasn’t just natural. It’s been clearly documented all over the world that humans have accelerated it because we blocked sand movement down the coast through structures, inlets, jetties, etc. In the big picture, three things cause erosion at Dauphin Island: sea level rise, storm activity and sand supply.’
As improved transportation opened the island to development, people began building throughout the unprotected west end of the island, including homes built right on the beach. Forests were cut, dunes leveled, and marshes filled. Exposed and unprotected, these new developments are vulnerable to storms and erosion, as evidenced by the destruction brought on by Hurricane Katrina in 2005 and the ongoing shoreline erosion. Desperate to save their homes, some homeowners have built seawalls, which protect one patch of land only to increase erosion on the adjacent shoreline.
The challenges facing Dauphin Island are echoed throughout the region, yet there are no easy answers when it comes to erosion. The best solution is the least popular, give fragile coastal environments back to nature and resettle elsewhere. Short of that, multi-faceted approaches including habitat rehabilitation and shoreline protection can ease erosion.
Shoreline Protection: Oyster Reefs at Helen Wood Park
With more than one-third of Mobile Bay’s shoreline stabilized by bulkheads and other man-made structures, protecting the remaining natural coastal habitats is crucial. Coastal marshes provide critical habitat essential to native species and local fisheries. At Helen Wood Park on Dauphin Island Parkway, The Nature Conservancy partnered with PEP member organization Alabama Power to provide erosion control along the shoreline to protect the coastal marshes from erosion.
Through a grant from Alabama Power Foundation and the man-power of volunteers from the Alabama Power Service Organization Mobile Division chapter, The Nature Conservancy restored seven oyster reefs at Helen Wood Reef and Breakfront. The team utilized an innovative new technology, constructing the reefs from a series of interlocking concrete blocks called Oyster Castles®. In addition to providing erosion control along the shoreline, the design enhances habitat for oysters, crabs, and other marine life along the reef.
The Nature Conservancy is monitoring progress at the reefs. “A December survey found all structures still intact and an increase in marine life around the area,” reports Erin Delaporte, division customer service manager and president of the APSO Mobile Division chapter. “Sediment build up indicates erosion control is working.”
Restoration: Mon Louis Island Coastal Marshes
Eroding shorelines not only impact natural environments, but put human lives at risk. Such is the case for the northern tip of Mon Louis Island, a coastal marsh at the mouth of East Fowl River in South Mobile County. The area was severely eroded and close to breaching. Like coastal marshes elsewhere, the shoreline habitat along Mon Louis Island serves as a buffer, protecting homes and infrastructure from storm tides and wave action.
In areas where coastal habitats have been degraded, shoreline protection must work in conjunction with restoration programs to rehabilitate coastal habitats. PEP Member organization Thompson Engineering took this two-fold approach when selected by the Mobile Bay National Estuary Program to lead restoration along this section of Mon Louis Island. Over the course of the project, Thompson created four acres of new marsh and built a rock breakwater, stabilizing the shoreline and enhancing aquatic, wetland, and upland habitats.
Dune Restoration: Gulf State Park
Coastal marshes are just one of many habitats comprising the Gulf Coast. Dunes, coastal ponds, swales, intertidal beaches, and sand scrub habitats all contribute to a healthy, functioning coastline, providing important habitat for a variety of wildlife and defending against storm surge and flooding. As part of the Master Plan and Enhancement Project, Gulf State Park recently underwent an extensive dune restoration project aimed at building healthy dunes more naturally.
Coastal dunes are a highly dynamic system, constantly shaped through water and wind. PEP Member organization Volkert, Inc. engineered the dune project to restore the natural systems effecting dune development allowing dunes to regrow themselves over time. The plan includes strategic cuts along a man-made berm built after Hurricane Ivan that will allow sand to migrate inland to rebuild interior dunes. To further encourage inland dune growth, discarded Christmas trees are being used in combination with native plantings to capture and stabilize windblown sand to form a patchwork of ridges and swales.
With a focus on restoring the natural dune building processes, Volkert and their partners are working toward a self-sustaining system. A healthy functioning coastal ecosystem maximizes the ability for the dune system to provide storm protection for people, while restoring critical habitat for the federally endangered beach mouse, nesting loggerhead and Kemp’s ridley sea turtles, and migratory shore birds.
These are just a few of the many ways PEP member organizations are working to improve the coastal environment. As understanding of coastal systems evolves and strategies to protect against shoreline erosion expand, PEP member organizations continue to stand at the forefront of innovation.