Natural Alternatives to Shoreline Erosion Protection
There are many types of waterfront property; some are nestled in quiet coves or small creeks, while others face open water and the waves that come with it. Some properties are suffering the effects of steady erosion, while others are stable or growing. For decades, despite the differences in shoreline types, there has mostly been a “one-size-fits-all” approach to shoreline protection – building bulkheads or installing rock or rip-rap revetments.
In recent years, we have learned much about the conditions that make a healthy river/Bay environment. Results of recent studies have shown that when compared to shorelines with vegetated marsh, hardened shorelines (bulkheads, rock revetments) have a lower abundance of bottom-dwelling organisms offshore and lower numbers of juvenile fish and crabs.
In many cases, where the waterfront is subject to waves of low to moderate energy, there are effective alternatives to shoreline hardening. These methods of shoreline protection are often referred to as “soft”, or “living” shoreline protection. Some of the benefits of this approach are
- Lower construction costs when compared to bulkheads and revetments
- Reduction of both sediment and pollutant flow into the creek or river
- Maintaining a link between aquatic and upland habitats.
- Creating a natural shoreline appearance.
- Restores or maintains critical spawning and nursery areas for fish, crabs and more.
In 2010, the Virginia Institute of Marine Sciences delivered a report to the Virginia General Assembly
(.pdf download) on the value of living shorelines. This report resulted in a 2011 law
that sets "living shorelines" as the preferred option for shoreline erosion control and sets up a general permit for living shorelines in Virgina.
Shorelines in creeks or coves that receive low energy waves can often be protected by methods other than building hard structures. Examples include (re)planting wetland vegetation and beach replenishment. These methods are appropriate if the property once had a vegetated wetland or beach, or if neighboring shorelines currently have vegetated wetland shorelines or beaches.
In marsh restoration projects, where no sand or sediment is added or removed, no regulatory permit may be needed, reducing both cost and time. However, you should always call your local wetlands board representative to be sure.
In locations with greater exposure to waves, it may still be possible to maintain a mostly natural shoreline. Three structural additions used for this purpose are near and offshore breakwaters, sills and low profile rock groins. Whereas the purpose of bulkheads and revetments is to reflect or absorb wave energy, sills, breakwaters and low rock groins are placed within the intertidal zone, or beyond the low tide mark to enhance sand buildup along the shoreline. In most cases, these structures are used in concert with beach replenishment and marsh plantings
Resources containing greater detail about Living Shorelines: