Beach Stabilization

Alternative Shoreline Stabilization Devices

Disclaimer

Traditional methods of stabilization - seawalls, groins and breakwaters - are increasingly being identified as leading to the erosion of fronting and downdrift beaches. For the last thirty years, coastal homeowners and town managers have sought low-cost, effective alternatives. In response, a number of "non-traditional" devices with optimistic sounding names have appeared on the market.

The following is a listing and brief description of many alternative devices. Also included is a qualitative analysis outlining the potential negative impacts of each device. It is important to note that few of these devices have been sufficiently field tested (five years or more to accurately assess the ability to withstand severe storms) while some have never been field tested at all.

Potential Negative Impacts

As an extension of the problems previously listed, devices were assessed as to associated negative impacts. This analysis is based on media reports, first-hand accounts and our own personal experience with shoreline devices and coastal processes. The following negative impacts were evaluated for each device:

  • Reduces Beach Access: This applies to any device placed on the beach that restricts lateral or cross-shore access, access to the water, or restricts swimming areas.
  • Erosion of downdrift beaches : Devices that restrict transport of sand, either cross-shore or alongshore will lead to erosion elsewhere.
  • Erosion of fronting beaches : Applies to devices that cause wave reflection, that prevent landward migration of beaches, or which cut off the local sediment supply.
  • Potential hazard to swimmers : A device placed in the shallow nearshore zone poses a threat to swimmers. Devices that alter currents or flow present a possible threat, especially when used in conjunction with a groin. Water that flows onshore must flow offshore. When offshore flow is impeded, water will flow along shore until it can be released, creating a separate longshore current. When a breakwater is placed near a groin there is usually a space between the two. This is the preferred path for water flow, and leads to the Venturi effect. Water that flows through a narrow, straight opening, will create an undercurrent suction, similar to that of a rip current. This could result in swimmers being pulled offshore.
  • Impact to water quality: A key factor in preserving water quality is dilution of pollution through circulation. A reduction in the flow of water, reduces the circulation and can effect water quality. This category applies to those devices that impede water flow, or that trap floating debris.
  • Impacts turtle nesting: Not only are devices that impede the path of turtles across the shore a concern, but more important, are those that may alter the temperature of the sand. The sex of turtles is determined by the temperature at which they are incubated. Devices that effect the temperature of the soil may cause overselection for one sex.
  • Impacts on clam resource: Of great concern, especially on the west coast, is the clamming industry. Any device placed on the nearshore, or at the low tide line may impact the access to the clams and the resource itself by compacting the sand.
  • Impairs aesthetics: One of the primary reasons for development along the coast is because people are drawn to its natural beauty. Devices that are placed on the beach or above water detract from the scenery and overall aesthetics.

Alternative stabilization devices survey:

Disclaimer:
Western Carolina University PSDS (including its employees and agents) assumes no responsibility for consequences resulting from the use of the information herein, (or from the use of the information obtained at linked Internet addresses,) or in any respect for the content of such information, including (but not limited to) errors or omissions, the accuracy or reasonableness of factual or scientific assumptions, studies or conclusions, the defamatory nature of statements, ownership of copyright or other intellectual property rights, and the violation of property, privacy, or personal rights of others. Western Carolina University PSDS is not affiliated with, nor do we endorse, any of the devices listed; is not responsible for, and expressly disclaims all liability for, damages of any kind arising out of use, reference to, or reliance on such information. No guarantees or warranties, including (but not limited to) any express or implied warranties or merchantability or fitness for a particular use or purpose, are made by Western Carolina University PSDS with respect to such information.

 

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