Why Sand Is Disappearing ( from beaches)

beachlooknorth

The heavily impacted Weir’s Beach which has experienced considerable sand loss in recent years largely due to bad management of the shoreline.

This article highlights a good example how human interference ( anthropogenic) in a number of ways can result in the loss of Natural Capital and long term sustainability . 

The beaches of Metchosin are not immune  to the forces of Climate change and uninformed decisions of upland landowners and municipal governments which refuse to enact rigid Shoreline Development Bylaws. 

This has been quoted  from: The NYT Opinion Pages    NOV. 4, 2014

” BERKELEY, Calif. — To those of us who visit beaches only in summer, they seem as permanent a part of our natural heritage as the Rocky Mountains and the Great Lakes. But shore dwellers know differently. Beaches are the most transitory of landscapes, and sand beaches the most vulnerable of all. During big storms, especially in winter, they can simply vanish, only to magically reappear in time for the summer season.

It could once be said that “a beach is a place where sand stops to rest for a moment before resuming its journey to somewhere else,” as the naturalist D. W. Bennett wrote in the book “Living With the New Jersey Shore.” Sand moved along the shore and from beach to sea bottom and back again, forming shorelines and barrier islands that until recently were able to repair themselves on a regular basis, producing the illusion of permanence.

Today, however, 75 to 90 percent of the world’s natural sand beaches are disappearing, due partly to rising sea levels and increased storm action, but also to massive erosion caused by the human development of shores. Many low-lying barrier islands are already submerged.

Yet the extent of this global crisis is obscured because so-called beach nourishment projects attempt to hold sand in place and repair the damage by the time summer people return, creating the illusion of an eternal shore.

Before next summer, endless lines of dump trucks will have filled in bare spots and restored dunes. Virginia Beach alone has been restored more than 50 times. In recent decades, East Coast barrier islands have used 23 million loads of sand, much of it mined inland and the rest dredged from coastal waters — a practice that disturbs the sea bottom, creating turbidity that kills coral beds and damages spawning grounds, which hurts inshore fisheries.

The sand and gravel business is now growing faster than the economy as a whole. In the United States, the market for mined sand has become a billion-dollar annual business, growing at 10 percent a year since 2008. Interior mining operations use huge machines working in open pits to dig down under the earth’s surface to get sand left behind by ancient glaciers. But as demand has risen — and the damming of rivers has held back the flow of sand from mountainous interiors — natural sources of sand have been shrinking.

One might think that desert sand would be a ready substitute, but its grains are finer and smoother; they don’t adhere to rougher sand grains, and tend to blow away. As a result, the desert state of Dubai brings sand for its beaches all the way from Australia.

And now there is a global beach-quality sand shortage, caused by the industries that have come to rely on it. Sand is vital to the manufacturing of abrasives, glass, plastics, microchips and even toothpaste, and, most recently, to the process of hydraulic fracturing. The quality of silicate sand found in the northern Midwest has produced what is being called a “sand rush” there, more than doubling regional sand pit mining since 2009.

But the greatest industrial consumer of all is the concrete industry. Sand from Port Washington on Long Island — 140 million cubic yards of it — built the tunnels and sidewalks of Manhattan from the 1880s onward. Concrete still takes 80 percent of all that mining can deliver. Apart from water and air, sand is the natural element most in demand around the world, a situation that puts the preservation of beaches and their flora and fauna in great danger. Today, a branch of Cemex, one of the world’s largest cement suppliers, is still busy on the shores of Monterey Bay in California, where its operations endanger several protected species.

The huge sand mining operations emerging worldwide, many of them illegal, are happening out of sight and out of mind, as far as the developed world is concerned. But in India, where the government has stepped in to limit sand mining along its shores, illegal mining operations by what is now referred to as the “sand mafia” defy these regulations. In Sierra Leone, poor villagers are encouraged to sell off their sand to illegal operations, ruining their own shores for fishing. Some Indonesian sand islands have been devastated by sand mining.

It is time for us to understand where sand comes from and where it is going. Sand was once locked up in mountains and it took eons of erosion before it was released into rivers and made its way to the sea. As Rachel Carson wrote in 1958, “in every curving beach, in every grain of sand, there is a story of the earth.” Now those grains are sequestered yet again — often in the very concrete sea walls that contribute to beach erosion.

We need to stop taking sand for granted and think of it as an endangered natural resource. Glass and concrete can be recycled back into sand, but there will never be enough to meet the demand of every resort. So we need better conservation plans for shore and coastal areas. Beach replenishment — the mining and trucking and dredging of sand to meet tourist expectations — must be evaluated on a case-by-case basis, with environmental considerations taking top priority. Only this will ensure that the story of the earth will still have subsequent chapters told in grains of sand.

Weir’s Beach erosion.

In July 2013 at Low tide, the loss of sand from near the south end of Weir’s Beach has become obvious. This was predictable because of the hardening of the shoreline several years ago with the installation of large rock rip-rap along the front of the adjacent Weir’s Beach Trailer Park. As many of the references such as  Hardening the shorelines indicates:  “Hard structures, especially vertical walls, often create conditions that lead to failure of the structure. In time, the substrate of the beach coarsens and scours down to bedrock or a hard clay. The footings of bulkheads are exposed, leading to undermining and failure. … Failed bulkheads and walls adversely impact beach aesthetics, may be a safety or navigational hazard, and may adversely impact shoreline ecological functions.”

riprap

Large rock riprap on the berm

trailers1

Trailer park perched on the edge of the berm.

weirserosion

Loss of fine sand material from the beach in front of the trailer park.

See this file for earlier images of the beach and comparisons: http://metchosinmarine.ca/7taylorbeach/weirs/beachcompare.htm

New Seawall on Weir’s Beach

Over the summer of 2013, a new seawalll was built at the south end of Weir’s beach. The purpose of the wall is not obvious, other than to create a walkway to the ocean for the residence above.
The provincial government owns the ocean floor and the foreshore (the area between the low water level and the natural boundary) along Metchosin’s Coastline. This structure sits within this foreshore area, as there is sand at it’s base,  so it is questionable how this shoreline modification was permitted.

UPDATE:

  •  Under the General  Marine Shoreline policies desired works require application to the appropriate Provincial/and or Federal agencies responsible.  This particular property located at 5289 William Head Road was able to proceed under the following conditions: 
  • 1. Requirements of the Department of Fisheries & Oceans must be fulfilled.
  • 2. Any work below the high water mark must have the approval of the Ministry Forests, Lands & Natural Resource Operations
  • 3.  Work was  conducted in April according to the measures outlined in the Ryzuk Geotechnical Report dated March 7, 2013 and the report by Lehna Malmkvist, Swell Environmental Consulting Ltd., March 8, 2013

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Readers are recommended to read all parts of the publication below before attempting any alterations on shorefront property:

Coastal Shore Stewardship: A Guide for Planners, Builders and Developers on Canada’s Pacific Coast

Another reference on hardening the shorelines states the problem rather plainly: “Hard structures, especially vertical walls, often create conditions that lead to failure of the structure. In time, the substrate of the beach coarsens and scours down to bedrock or a hard clay. The footings of bulkheads are exposed, leading to undermining and failure. … Failed bulkheads and walls adversely impact beach aesthetics, may be a safety or navigational hazard, and may adversely impact shoreline ecological functions.”

southendstairnorth

View of the seawall from the south.

southendstairway

View of the seawall from the beach directly in front.

seawallfrombeach

View of sea wall from the north.

Hardening of the Shorelines: Principles

The following is from :
Shorelines Modification , by the State of Washington Dept of Ecology

(ii) Principles. Shorelines are by nature unstable, although in varying degrees. Erosion and accretion are natural processes that provide ecological functions and thereby contribute to sustaining the natural resource and ecology of the shoreline. Human use of the shoreline has typically led to hardening of the shoreline for various reasons including reduction of erosion or providing useful space at the shore or providing access to docks and piers. The impacts of hardening any one property may be minimal but cumulatively the impact of this shoreline modification is significant.

Shoreline hardening typically results in adverse impacts to shoreline ecological functions such as:

  • Beach starvation. Sediment supply to nearby beaches is cut off, leading to “starvation” of the beaches for the gravel, sand, and other fine-grained materials that typically constitute a beach.
  • Habitat degradation. Vegetation that shades the upper beach or bank is eliminated, thus degrading the value of the shoreline for many ecological functions, including spawning habitat for salmonids and forage fish.
  • Sediment impoundment. As a result of shoreline hardening, the sources of sediment on beaches (eroding “feeder” bluffs) are progressively lost and longshore transport is diminished. This leads to lowering of down-drift beaches, the narrowing of the high tide beach, and the coarsening of beach sediment. As beaches become more coarse, less prey for juvenile fish is produced. Sediment starvation may lead to accelerated erosion in down-drift areas.
  • Exacerbation of erosion. The hard face of shoreline armoring, particularly concrete bulkheads, reflects wave energy back onto the beach, exacerbating erosion.
  • Ground water impacts. Erosion control structures often raise the water table on the landward side, which leads to higher pore pressures in the beach itself. In some cases, this may lead to accelerated erosion of sand-sized material from the beach.
  • Hydraulic impacts. Shoreline armoring generally increases the reflectivity of the shoreline and redirects wave energy back onto the beach. This leads to scouring and lowering of the beach, to coarsening of the beach, and to ultimate failure of the structure.
  • Loss of shoreline vegetation. Vegetation provides important “softer” erosion control functions. Vegetation is also critical in maintaining ecological functions.
  • Loss of large woody debris. Changed hydraulic regimes and the loss of the high tide beach, along with the prevention of natural erosion of vegetated shorelines, lead to the loss of beached organic material. This material can increase biological diversity, can serve as a stabilizing influence on natural shorelines, and is habitat for many aquatic-based organisms, which are, in turn, important prey for larger organisms.
  • Restriction of channel movement and creation of side channels. Hardened shorelines along rivers slow the movement of channels, which, in turn, prevents the input of larger woody debris, gravels for spawning, and the creation of side channels important for juvenile salmon rearing, and can result in increased floods and scour.

Additionally, hard structures, especially vertical walls, often create conditions that lead to failure of the structure. In time, the substrate of the beach coarsens and scours down to bedrock or a hard clay. The footings of bulkheads are exposed, leading to undermining and failure. This process is exacerbated when the original cause of the erosion and “need” for the bulkhead was from upland water drainage problems. Failed bulkheads and walls adversely impact beach aesthetics, may be a safety or navigational hazard, and may adversely impact shoreline ecological functions.

Hard” structural stabilization measures refer to those with solid, hard surfaces, such as concrete bulkheads, while “soft” structural measures rely on less rigid materials, such as biotechnical vegetation measures or beach enhancement. There is a range of measures varying from soft to hard that include:

  • Vegetation enhancement;
  • Upland drainage control;
  • Biotechnical measures;
  • Beach enhancement;
  • Anchor trees;
  • Gravel placement;
  • Rock revetments;
  • Gabions;
  • Concrete groins;
  • Retaining walls and bluff walls;
  • Bulkheads; and
  • Seawalls.

Generally, the harder the construction measure, the greater the impact on shoreline processes, including sediment transport, geomorphology, and biological functions.

The Effect of Seawalls

“Seawalls damage virtually every beach they are built on. If they are built on eroding beaches—-and they are rarely built anywhere else,—-they eventually destroy the beach. ”  –Cornelia Dean, (Science Editor of the New York Times) Against the Tide, The Battle of America’s Beaches 53 (1999) 

A serious problems which has developed on the coastline  of Metchosin, is the building of seawalls under the pretext of protecting private property from erosion. Owners of properties along a coast are often not aware of the mechanics of the interaction with ocean energy of the shoreline. After an intense storm, evidence of erosion along a shore-front often leads land owners, desperate to save their property to go to often very expensive extremes in order to try to protect their property.

A survey of literature from various parts of the world indicates this is not only a local problem, but is indeed very wide spread. The series of photographs documented on this website from Puget Souperkinslane_pugetsoundnd, show the problem not far from our shores. We should consider ourselves lucky so far in Metchosin as we have yet to experience the disasters that have happened in Puget Sound.  This link to an Image Gallery shows how bad it could get:

 

Impact of Coastal Erosion in Australia 7 Mar, 2013
Senior Coastal Scientist at Coastalwatch Professor Andrew Short has compiled a comprehensive piece focusing on coastal erosion in Australia.

For the 50% of the Australian coast that is composed of sand and in some places mud, the shoreline is prone to change, building seaward and in some places eroding landward. In most locations this is a natural process with usually no impact on human settlement. Coastal protection of the shoreline is rarely required in Australia, however in a few locations the dynamic shoreline has become a problem, in some cases a major and expensive problem, and in almost all of these cases the problem is related to human interference or encroachment on the shoreline. Coastal protection works, such as breakwaters, groynes, or seawalls, are usually built to guard against erosion. In doing so they harden the coast and reduce its ability to adjust naturally. As a consequence, these defences can exacerbate further erosional problems, with seawalls reflecting and concentrating wave energy and erosion, and groynes starving downdrift the coast of sediment thereby leading to further erosion. There are areas where human have encroached into the dynamic beach environment only to suffer the consequences, and others where they have interfered with coastal processes leading to accelerated coastal erosion.

The Utilization of Seawalls in Response to Shoreline Erosion Consequences, Socio-Economic, Political and Legal Forces, and Alternatives Shawn W. Kelly , Donald Bren School of Environmental Science and Management University of California, Santa Barbara November 30, 2000

Executive Summary
See the full PDF version: Seawall

seawallWhen coastal buildings or roads are threatened, the typical response is to harden the coast with a seawall. Seawalls run parallel to the beach and can be built of concrete, wood, steel, or boulders. Seawalls are also called bulkheads or revetments; the distinction is mainly a matter of purpose. They are designed to halt shoreline erosion caused primarily by wave action. If seawalls are maintained, they may temporarily hold back the ocean from encroaching on shoreline development. In spite of their ability to hold back the ocean, when waves hit a seawall, the waves are reflected back out to sea, taking beach sand with them and eventually causing the beach to disappear. Moreover, seawalls can cause increased erosion at the ends of the seawall on an adjacent beach that is not walled. Alternatives to seawalls exist, such as beach nourishment and managed retreat. Making coastal land use decisions that ensure a seawall will not be needed in the
future to protect structures, however, is the most prudent coastal management solution. This can be accomplished by establishing setback lines and conducting managed retreat of structures that are threatened by shoreline erosion before the situation worsens, or structures that have the potential for being threatened in the future. Regional case studies are presented to illustrate.
And finally an amusing story about coastal erosion and the origin of the term

“The Streisand effect”

The following excerpt from George Monbiot ( on SLAPP suits) mentions a very interesting case :

In Canto 21 of the Inferno, Dante watches lawyers who made a habit of bringing frivolous or oppressive suits being perpetually submerged in a lake of boiling tar by demons with boathooks. They get off quite lightly, in other words. But perhaps hell of a different kind awaits on earth. It’s called the Streisand Effect. In 2003 Barbra Streisand’s lawyers launched an action to have an aerial photograph of her home in Malibu removed from a collection of 12,000 such shots, whose purpose was to document coastal erosion(11). They demanded $50m in damages. Before they became involved, the photo was downloaded four times. In the month after they launched their stupid suit, it was downloaded 420,000 times(12). “The Streisand Effect,” in other words, is blowback: disastrous unintended consequences of an attempt at censorship.”

 

Climate Change, Coastal Erosion and Seawalls

These links to external sources on this post are focused on the interactions with Humans in Coastal Areas.

waterfront_cottage CRD– Limit the Impacts of Shoreline and Streamside Development
KONICA MINOLTA DIGITAL CAMERA CRD–Protecting Shorelines and Streamsides
rockyshores CRD –Rocky Shorelines
structures Shoreline Structures Environmental Design ( pdf file) –
A Guide for Structures along Estuaries and Large Rivers
greenshore From Green Shores–The Green Shores program promotes sustainable use of coastal ecosystems through planning and design that recognizes the ecological features and functions of coastal systems.
coastalsediment Coastal Sediment Processes
climchange Climate Change and Coastal Shores In British Columbia
CoastErosionTH Center for Ocean Solutions:
Coastal Erosion and Climate Change
olympia Climate Change : Pacific NW of USA
Impacts on Coastal Areas
seawallclimchange

CRD Coastal Process

Image

This booklet was written in the 1970’s based on the report done by Dr. Wolf Bauer.

Click on the icon of each page of the gallery to view.

 

Metchosin Marine Issues, an Expression of Concern.

The Unique Value of our Coastal Ecosystems

The Coastal Resources of Metchosin are a valuable form of Natural Capital that must have special consideration when Development Planning is done in the District.   The Crown owns the foreshore to the high tide mark, and although one would think this allowed protection, there are still considerable threats to the ecological integrity of this area, which must be considered. The shoreline is an interface between two systems, the terrestrial uplands and the open ocean. As typical of any natural system, one cannot separate them in terms of management decisions, as they have processes, which interact.   Community members of a progressive coastal community should tolerate no activities involving human action that contribute to any level of destabilization or decline of our present shoreline ecosystems.

Along our shorelines in Metchosin, we have a variety of unique marine ecosystems.

  • Tidal marshes,
  • lagoons,
  • estuaries,
  • bays,
  • eel-grass beds,
  • high speed current channels,
  • underwater caves,
  • vertical underwater cliffs,
  • boulder beaches,
  • sand beaches,
  • and pebble (pocket) beaches.

Every metre of coastal intertidal zone also has a characteristic set of organisms, which can be impacted by actions of humans either from the land side or the ocean side.  Larger commercial species of fish often feed or spawn near the shoreline interface, juvenile fish migrate along shorelines, often relying on protective habitat of overhanging vegetation or kelp beds, and the energy flow in the food webs of at least 7 local marine mammal species are directly affected.

It is further recognized that a viable commercial crab fishery, as well as an extensive sports fishery operates along the coastal areas of Metchosin.

Rockfishconservationareas19_20 The ocean environment in the area of Race Passage has also been recognized as an important habitat for the regeneration of Rockfish stock leading to the creation of a DFO rockfish conservation areas where all fishing is prohibited.

 

 

 

anthroimpactThis file and map of the the Metchosin Shoreline shows the major areas where humans have modified the habitat, often resulting in ecosystem modification and loss of habitat for local species of fish, invertebrates and marine mammals. The term Anthropogenic refers to human modification.

 

ecoareasThis file contains a map with the ecologically sensitive areas of Metchosin’s Coastal Ecosystems.
Terrestrial Threats:

  • Erosion from road building, utility and sewer installation, subdivision development carrying silt into the receiving waters has a negative impact on filter feeders (e.g. Clams, mussels and anemone) in the ocean.
  • Crushed rock deposited in upland areas in road building and building lot creation may have serious toxic impacts on marine life as water leaches through it carrying dissolved metallic ions to the sea.
  • Accidental or planned deposition of hazardous materials in soils can also lead to leaching to the marine waters.
  • Deforestation on upland slopes leads to deterioration of coastal ecosystems.
  • Channelization of streams leads to silt output and increased fresh water flow to ocean environments.
  • Human traffic, (especially horses) on beaches can severely impact on spawning areas of needle fish (on Taylor beach)
  • Uncontrolled dogs can have a serious impact on feeding patterns of shorebirds- especially crucial during migration.
  • Humans and dogs on beaches can impact on molting elephant seals.
  • Beach debris can be washed seaward, to be ingested by marine animals.
  • Oil and chemicals from storm sewer drains is toxic to marine creatures.
  • Building too close to cliffs can lead to destabilization and therefore slumping of land into the ocean. This is especially of concern along the cliffs of Parry Bay and Albert Head.
  • Sewage disposal on land in septic fields, contributes a large nutrient load as it leaches through to the shoreline. The heavy die-off of algal growth on Weir?s beach annually, is evidence of this.
  • Development on the coastline as has recently occurred South of Devonian Park can lead to alteration of the coastal resource, habitat smothering and destruction, and increases shoreline erosion risk.
  • Backshore alteration of any beach habitat for intended purposes of bank stabilization, inevitably in the long run leads to shorefront habitat deterioration.

Marine Threats:

Tanker traffic very close to our shores, poses a continual risk of oil and chemical spills. In the areas shown in the map, red indicates highly sensitive and a long term residency of oil. Yellow indicates a lesser residence time of oil. Green indicates a faster cleanup may be possible because of exposure to waves and currents.

  • Increase in cruise lines in recent years has a potential to impact our coastal resources.
  • Increasing fast boat traffic is hazardous to harbour seal pups and slow moving marine mammals (such as elephant seals) in particular.  It also increases rates of coastal erosion in sheltered bays.
  • Boat motor sound underwater affects animals relying on the underwater seascape for communication.
  • whalewiseWhale watching boating patterns have an impact on the time whales can spend foraging in the area.

 

 

  • Antifouling compounds on ships (some military) and in boats in marinas provide a further risk to the marine environment

Return to MetchosinCoastal

Originally published by G.Fletcher in 2004.