In the 1970's, an alternative to Beach Dredging, was
proven in multiple parts of The United States. This
technology, properly entitled "The Sandgrabber", used a
system of light weight blocks, that would allow the sand to
settle on the beach side of the tide. The Sandgrabber
showed promising results in both Coastal and Lake based
applications, including installs in Hawaii, Ontario, Massachusetts
and even Louisiana, as recent as 1995. As all
innovations conceived by man, The Sandgrabber still required
some advancements to solidify the technology for use by
today's current standards and regulations.
Unfortunately, many less capable, less engineering
minded companies, told the folks at Sandgrabber, their
desires and wishes could not be achieved, this continued for
nearly 30 years.
Notice, that even 30 years later, The Sandgrabber
system did in fact build a wide distance of linear footage,
extending the length of the installation!
The Sandsaver, is the improved technology, that
hundreds if not thousands, said could never be produced. The World-Leading Engineering at The
Granger Plastics Company not only said the unit could be
done, they also proved it, by tooling up and producing modules.
The 1970's model of Sandgrabber, which was proven
effective, had a couple of key drawbacks that kept many from
utilizing the enormous cost saving and safe technique of
beach re-nourishment:
The Sandsaver, improved on all concerns raised by experts
who had utilized or questioned The Sandgrabber system.
The first issue, was the weight or density of the
system when installed. The sandgrabber
system, consisted of numerous, light weight, concrete cinder
blocks. Even though, this proved to work in multiple
locations and even still stands over 30 years later at an
install location in Hawaii, the weight was viewed as a
concern, due to any potential threatening storms, that could
move, damage or shift the Sandgrabber installation location.
The onset of storms actually increased the results seen by
The Sandgrabber system, but due to the light weight blocks,
the system was viewed as vulnerable. The Sandsaver
directly removes any inclination of being too light, with
each module weighing approximately 5,200 pounds,
concerns of weight are a thing of the past. The Sandsaver
utilizes USDA/FDA food grade materials, to encompass all
surfaces of up to 5,000 pounds of material in each
module.
The Sandsaver performs in 2
manners; First by breaking down the energy of the wave, thus
reducing erosion on the beach. Secondly, it allows the
wave, which contains large amounts of sand and beach
sediment, to pass through the tapered holes and onto the
beach surface. When the water retreats, it has to pass
through the small portion of the module allowing the sand
time to settle onto the beach and not back into the surf,
thus buidling beach.
COMPARISONS TO OTHER SYSTEMS
-Dredging- (Also known as Beach
renourishment)
Dredging or the more "politically accepted term" known as
"Beach renourishment" has became some what of the "norm" in
terms of solving the age old problem of Beach erosion.
Dredging, involves the transport of the nourishment material
(Sand & Sediment) from one area (usually further into the
surf) then pumped to the affected area. This process
is generally extremely expensive (minimum of $1
million/mile), depending upon the source. Dredging,
unfortunately up to this point is commonly used as a
replenishment method. A poorly-designed or executed
Dredging project can actually do more harm the impacted
ecosystem, regardless of how much maitenance and expense is
taken to deal with the sustainability of the littoral
environment. Once a beach has been "renourished" it is
almost standard, that it will always require regular Beach
dredging/renourishment, since it has been proven that
dredged or "renourished" beaches erode faster than natural
beaches. The socio-economic activity that is generated
from beach tourism may compensate for the cost of both
capital and maintenance for dredging projects, but only in a
small number of heavily urbanized or locations that see
large Tourist revenues. Not only is the financial
burdens of dredging severe, along with temporary, it also
negatively affects the ecosystem of the waters and of the
beach. Dredging causes direct mortality to many
organisms and animals. Contingent upon the type of
dredging equipment used, whether a Hopper Dredge, A
cutter-head suction pipeline dredge, Grab Dredge or a
Side-Cast Dredge, living organisms whether they are Sea
Turtles, Fish, Fauna or others are all adversely
affected or even killed. The more commonly used
"Hopper Dredger" is well known to "take in" Sea Turtles via
it's suction pipes along the seafloor. I doubt that
they use "take" in an animal sound/friendly sort of
way.
Recently, CBS
News ran the following story, highlighting not only the
enormous burden that is being placed on all tax paying
citizens, but the short lived results that are produced at
such outlandish costs, only to be repeated in a short period
of time.
A groyne (groin) is a rigid hydraulic structure built from an
ocean shore (in coastal engineering) or from a bank (in rivers)
that interrupts water flow and limits the movement of sediment
that is moved or eroded away. In the ocean, groynes create
beaches, or avoid having them washed away by longshore drift. In
a river, groynes prevent erosion and ice-jamming, which in turn
aids navigation. Ocean groynes run generally perpendicular to
the shore, extending from the upper foreshore or beach into the
water. All of a groyne may be under water, in which case it is a
submerged groyne. The areas between groups of groynes are groyne
fields. Groynes are generally made of wood, concrete, or rock
piles, and placed in groups. Groynes are common and require
little maintenance. They are often used in tandem with seawalls.
Groynes, however, may cause a shoreline to be perceived as
unnatural and ugly. Pictured below are examples of Groynes.
The picture at the top shows 13 groynes on a beach in Portugal.
The pictures below show 2 beaches, with numerous groynes installed.
Basically the idea of a groyne is to prevent longshore drift.
Groynes are generally cheap in comparison to dredging
alternatives. The purpose of a groyne is to create and maintain
a wide beach on its updrift side, primarily for recreation, but
also for protection to the land behind. First, groynes act as a
barrier to physically stop sediment transport (sand) in the
direction of longshore transport through the system. This causes
a build-up of the beach on the groyne's updrift side. However,
this is often accompanied by accelerated erosion of the
downdrift beach, known as terminal groyne syndrome, as it occurs
after the terminal groyne, which receives little or no sand via
longshore transport. It is important to understand that groynes
do not add any new sand to the beach, but merely retain some of
the existing sand on the updrift side of the groin. If a groyne
is correctly designed, then the amount of material it can hold
will be limited, and excess sediment will be free to move on
through the system. However, if a groyne is too large it may
trap all the sediment reaching it and this can cause severe
beach erosion problems on the down-drift side. As you can
see from the pictures above, groynes are also very unsightly and
generally de-tract tourists to that particular area of beach.
Groynes may be permeable, allowing the
water to flow through at reduced velocities, or impermeable,
blocking and deflecting the current. Permeable groynes are
fabricated from piles, bamboo or timbers, whereas impermeable
groynes (also called solid groynes or rock armour groynes) are
constructed using rock, gravel, gabions, etc.
Groynes may be designed either as submerged or as
non-submerged under normal conditions. Which of the two types
will be used is dictated by the design conditions. Usually
impermeable groynes are designed to be non-submerged, since flow
over the top of solid groynes may cause severe erosion along the
shanks. Submerged groynes, on the other hand, may be designed
permeable, depending on the degree of flow disturbance that is
needed.
Groynes may be classified as attracting, deflecting or
repelling. Attracting groynes point downstream, they serve to
attract the stream flow toward themselves and do not repel the
flow toward the opposite bank. Deflecting groynes are generally
short ones and used for local protection. They serve to change
the direction of flow without repelling it. Repelling groynes
point upstream. They serve to force the flow away from
themselves.
Groynes may be built with different plain view shapes. Examples
are straight groynes, T head, L head, hockey stick, inverted
hockey stick groynes, straight groynes with pier head, wing, or
tail groynes.
- Coastal Armoring
Coastal Armoring is a manmade structure that is designed to either prevent erosion of the upland property or protect eligible structures from the adverse effects of coastal tides and current action. Examples of Coastal Armoring include seawalls, revetments, bulkheads, retaining walls, sloped boulder revetments, sloped geo-textile revetments, geo-textile dune scour protection, or other similar structures.
Environmental impacts of coastal armoring are both site specific and cumulative. The effects vary depending on the type of structure that is being constructed for Beach protection. Also, the magnitude of the project, the specific geological, biological and oceanographic conditions in the vicinity of the coastal armoring structures. The impacts of an individual project need to be evaluated on a situational basis. Coastal armoring can potentially damage or alter local coastal habitats. They also deprive other areas of beaches sand, which leads to accelerated erosion of adjacent beaches. All types of Coastal armoring also hinder beach access and present potential issues with public and property safety.
INSERT CONS OF COASTAL ARMORING GRAPHIC
As with any activity that alters a natural process, there can be significant long-term impacts related to coastal armoring. Currents, waves and wind normally transport sand and sediment throughout the littoral system. Coastal Armoring can interfere with littoral transport, which in a natural state may reach a dynamic equilibrium. When sand & sediment availability is reduced due to the existence of a coastal armoring structure, erosion can begin to increase in other nearby locations. This is due to the starvation of the materials that would normally supply these areas. When a coastal armoring structure is constructed and installed, a supply of sediment is also effectively being cut off. Armoring also causes deflection of the wave energy, thus accelerating erosion of nearby, unprotected sites, expanding the need for even more coastal armoring. In some cases, installing coastal armoring only begets more coastal armoring. Furthermore, armoring can result in the loss of beach and intertidal area through a process that has been termed "passive erosion". Areas that undergo long-term net erosion
experience a natural landward movement of the entire beach system during periods of sea level rise; Such has been the case for the last 18,000 years (approximately). As cliffs and sand dunes retreat, the vacated area becomes part of the beach environment and the position of the beach shifts landward. Building a protective structure in front of a cliff or dune will temporarily stabilize the seaward location of the cliff or dune edge, but regardless, the beach erosion continues. Since no new beach area is created through cliff or dune retreat, a net loss of beach actually occurs. Ultimately, as erosion continues, this process also will result in the loss of the intertidal zone, as waves impact the seawall at all times, low tide as well as high tide.
