Beach Reclamation
SOURCE : http://www2.gsu.edu/~mstnrhx/EnviroBio%20Projects/Beachfront/reclamation.html
What is beach reclamation?
Beach reclamation is the act of reclaiming a beach from erosion. In other words sand is added to the area that was lost to erosion "reclaiming" the shoreline that once was. Reclamation does not just occur on ocean beaches but any beach or shoreline that is subject to severe erosion.
How is it done?
Beach reclamation is often done through a process called dredging. Dredging is the process of scooping from the bottom of a water source a material. You may have heard of dredging when a person has drowned. Police dredge or take a device along the bottom of the body of water in an effort to locate the body of the victim. However, in beach reclamation the material retrieved is sand. The use of a vacuum-like device is often used in areas like lakes and rivers to obtain the sand.
Once the sand is obtained, it is deposited at the site. Sand is either directly applied or the sand that has been gathered is cleaned through a heat process and then deposited. The sand extends the shoreline to its orginal borders or extends the beach farther into the body of water it is adjacent to.
Below is an example of dredging from the Dredge and Dock Company Site. They contract under the Army Corps of Engineers for beach replenishment.
Sand siphoned up from the ocean floor, being deposited in one of the hoppers of the Dredge Long Island
With all the hoppers full, the Dredge Long Island heads towards the beach bringing sand from distant borrow areas. This dredge has a capacity of over 16,000 cubic yards of sand and can pump sand ashore from a buoy located off the beach.
In the background the Hopper Dredge Long Island, hooked up to a buoy, pumps a slurry mixture of sand and water ashore through a half mile of 27" diameter pipe.
Prior to beach replenishment the shoreline encroaches very near the boardwalk putting it in danger from coastal storms.
After beach renourishment, the shoreline is located further away from existing structures, protecting them from damage caused by coastal storms as well as providing a clean recreation area on the beach.
Why is it done?
The purpose of beach reclamation is to protect development properties from storm damage, extend beaches for public use, and to re-establish sand bars (also protection from storms). Without an adequate barrier between large bodies of water like oceans, beachfront properties are at risk from storms and erosion. The owners of these properties have a lot invested in their buildings and businesses and do not want to have them destroyed by high tides, hurricanes, or pounding waves caused by sea storms. Some sand bars that protected areas like the Barrier Islands of South Carolina as well as the islands themselves are subject to severe erosion and are the "speed breakers" of storms coming inland. When these are destroyed by erosion there is nothing to protect the properties inland. Reclamation becomes a source of replacing the "speed breakers" and dredging is the most common means to replace them.
What Problems Are Involved in Dredging?
One problem with dredging is the cost. The cost is on-going just as the erosion is on-going. Dredging does not stop erosion. It just adds more sand to erode. In some cases, dredging has cost communities up to 90 million dollars in total costs! The cost often exceeds the possible benefits of the beach nourishment.
Another problem is habitat destruction. When sand is added, it is not often done with consideration of the plants and animals that exist on the beach. It is like putting a sandbox in a yard. The plants and animals can often be smothered by the sand. The other aspect of habitat destruction is dredging takes animals and plant life from the bottom of the body of water being used to retrieve sand. The act itself is destructive to coral and other animals that may use the area for feeding, breeding, or living purposes.
Dredging also changes the face of the area sand is gathered from. The change in the geography could very well cause erosion in other areas because it shifts the way the land lies. Extending beaches into a body of water may also cause harm in that as more land becomes available people extend with it. The land extensions are often not stable. The land has a tendency to shift, flood, or sink without notice as pockets fill in or nature tries its own form of reclamation.
Are There Other Methods?
According to Holmberg Technologies, their method is the best. It promotes natural beach nourishment or reclamation. Their method is best described in the article from their site:
"Undercurrent Stabilizer Technology neutralizes the impacts dredged channels have on sandy beaches. This has proven to routinely reverse unnatural erosion. The technology consists of modular, hydrodynamically shaped forms which are cast in place on the nearshore seabed, generally at right angles to the shoreline. Problems normally associated with erosion control structures are avoided through tapered, low-relief shaping, special landward tie-backs and patented filter fabric foundations.
The low-profile, flow-through array (sometimes simply called "speed bumps") progressively baffles unnatural nearshore turbulence, allowing sand to fall out of suspension in quieted waters within and adjacent to the treated area. Local shoaling progressively decreases remaining nearshore turbulence (beyond decreases induced by the system itself). As the nearshore progressively shallows out in response to the accretion template, less and less wave and current energy is supported to drive arriving sand from the treated area.
Upon treatment, unnatural erosion ceases and resedimentation begins, often with surprising speed. The accretion template itself is generally buried by rising sand levels as the nearshore beach profile becomes inherently accretional. Adjacent shorelines benefit because an unbounded feeder beach is established. A long-term university study of numerous installations concludes: 'Consistent profile volume gain measured in the vicinity of the Undercurrent Stabilizer system (relative to a regional trend of profile volume loss) plus significant foreshore/backshore beach accretion with no apparent negative impact down drift must be viewed as success in almost any context'" (Holmberg Technologies 1999).
Graphics from the same site show how their product works in reestablishing beaches.
They say their product is longer lasting at a lower cost than dredging. Some communities in Texas and Florida have opted for this type of beach reclamation.
Problems associated with type of reclamation are erosion of downdrift beaches and creation of rip currents that are hazardous to swimmers. There does not seem to be much documentation to support any other problems. Yet, one still has to wonder about habitat destruction with the implementation of this technology into the water.
With beach reclamation, there seems to be no easy answers. Maybe you can come up with an environmentally friendly way to save the beaches and protect the developments as well.
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