How an “EnviroShore Stabilization System” (ESS) Works
While the math is complicated, the concept is simple…
Our engineers design and properly position “stabilizer tubes” (the ESS) on the near shore that mimic the type of geology that causes natural beach accretion. Water flowing over the ESS creates a vortex, reducing and absorbing longshore (littoral drift) currents and wave energy, capturing the sand within the ESS system.
Why is an ESS beach so much more stable than a “dredge-renourished” beach?
Sand accretion on this type of “induced” profile is correctly sequenced with respect to grain size distribution, called stratification. Generally, larger materials fall first and resist the initial high energy surf. Because NATURAL processes guide the re-sedimentation process, this new beach is more stable, resilient and durable. Less and less sand travels to the offshore loss point. As the beach grows, it becomes progressively more efficient at holding sand arriving from offshore sources. Over time, the natural beach building cycle is restored, and normal beach elevation levels are returned.
Typically these stable, accretive beaches continue to grow and hold sand, becoming “feeder beaches” to adjacent beach areas (both upstream and downstream). Feeder beaches are a significant source of sand for adjacent areas.
(Photo, right) Two separate systems were used to recover the entire shoreline pictured.
the ESS (pictured in first photo), by HTI in 2001. Still working today.
Dunes and Back Beaches:
The sand from the new feeder beach, combined with onshore wind helps to regrow dunes lost to erosion. Dunes and the back beach are a critical defense measure for minimizing flooding. Depleted, eroded beaches will typically lose their dune structure because they do not have a constant supply of sand to maintain a healthy dune. Dunes are lost to wind erosion and waves undercutting the toe of the bluff.
Without a sustainable, accretive beach, you can’t have sustainable dunes!
With ESS, the beach erosion process is stopped immediately after installation. Unlike typical “renourishment” methods, rough weather and storms are not worrisome. When you have a high surf event, the immense power will move a larger bedload of sediment. More sand in the system, the faster beaches are recovered.
This technology has been extensively studied and scientifically modeled. The model scene above was created during an “optimization testing” for a system in Greece. The company has successfully installed 29 systems throughout the area. This new modeling software took 4 years to develop and was designed to incorporate many more parameters and data points for testing the ESS technology.
Low Impact Solutions to Combat Beach Erosion
Extensive research into low impact solutions to beach erosion has been going on since 2000. This technology (ESS) was featured at the scientific “Soft Shore Convention” held in Europe, back in 2000, as an effective way to mitigate severe erosion without using “hard structures”. In their report, The European scientific community considers ESS-type technology a “soft shore, low impact” method of remediation.
Another benefit is that ESS-type technology will mitigate many of the downstream negative effects normally seen after dredge projects, jetties, or groin projects are completed. Adjacent beach erosion is often cited after a dredge project is completed, depending on the borrow source.
History of traditional barriers are part of the problem.
While hard structures and coastal armoring will protect the land behind them, all of the surf energy will be redirected back into the surrounding areas adjacent to the walls, or downward into the softer bottoms. This will cause deepening in front of the wall, and ultimately structure failure. That’s why it’s often said that “the only solution to a failed seawall… is a BIGGER seawall.”
What are Hard Structures:
Hard structures, like those pictured above, typically work by using mass to “reflect the energy” away from the beach. Hard structures are well known to shift, and exacerbate, erosion to the area adjacent to the armored areas. Areas with seawalls no longer have beaches, they have disappeared permanently (there is a reason you’ve never seen a healthy beach in front of a seawall or coastal armoring). Fortunately, most locations in the U.S. and Europe no longer allow these methods, except under emergency situations. The U.S. Army Corp of Engineers has documented the problems with hard structures and shoreline armoring since the early 1970’s.
The Better Way…
Soft Protection Methods to “Reduce Destructive Energy”
“Soft protection” are the preferred methods worldwide. Soft protection methods absorb and de-energize erosive energy, such as creating sand dunes, and plantings to protect and “hold the sand”, and the Enviroshore Stabilization System (ESS).
ESS is a permeable solution and does not stop the current flow (water passes over the system’s ‘fingers’) but slows the energy by redirecting it into “de-energizing vortices”, having the sand drop out of suspension as the speed of the water slows. Once the erosion is stabilized, we encourage our 5-step Beach Restoration Process to improve naturalization, stabilization and the long-term restoration of the beaches.
All ESS are designed for a low environmental impact footprint, safety for beachgoers, permanent and maintenance-free service after initial installation.
Learn more about the 5-step Beach Restoration Process on the environmental benefits page.