Oceanography: Our disappearing beaches
by Dr J Floor Anthoni (2000)
Beaches are made of sand washed up from the sea. Their dried sand is blown by the wind into dunes. Storms may damage dunes and beaches but waves and wind soon repair them. Yet beaches all over the world are shrinking or disappearing. Why is this happening? Are we to blame? What can we do about it? 
The findings in this section on why our beaches are disappearing, are original, controversial and thought provoking. Could it be possible that we have been doing exactly the wrong things to save our beaches? Read on, to understand why this is probably so (Introduction on this page, 3 pages).
Beaches are formed by the forces of waves and dunes are built by the sea wind. Like living organisms they absorb energy and change their shapes in reaction to changing circumstances.  Whereas headlands erode, beaches can hold their own. They have likes and dislikes, are healthy, sick and can die. (5 pages)
Hydro dams prevent the sand arriving from eroding soils above them, to reach the sea. Rising sea levels could gradually drown the dunes and beaches. Are these real threats? (3 pages)
Before sand can be blown by winds to build or repair dunes, it must first be dry. This poorly understood process is rather critical. Beaches can be too flat or their sand may form crusts. A beach that won't dry, will die. (4 pages)
Without sea wind, dunes cannot acquire sand. Yet many human activities have obstructed this process, resulting in coastal problems. Shells found on beaches have their own story to tell. (5 pages)
Dunes need to roll in order to transport excess sand from the beach inland. But for decades humans have been obstructing this process by attempting to stabilise the sand, resulting in permanent damage to both dunes and beaches. (6 pages)
Because sand is easily transported by water and wind, it causes problems both where it accumulates and where it depletes. For hundreds of years engineers have provided solutions, often with mixed long-term successes. (10 pages)
What are the causes of beach erosion? Can we save our beaches? What can you do to detect whether a beach i healthy or not? (9 pages)
Dune, beach and sea sand is clean and of good quality to satisfy society's growing demand for it. But can it be mined sustainably? Would sand mining affect the beaches? How can reasonable limits be set? A case study of sand mining in New Zealand with new information. (28 pages)
A summary of what we still need to know about beaches, in order to understand them fully. This research may prove or disprove but at least improve this section. A challenge to engineers and beach scientists. (3 pages)
Books and references (listed on this page)
Sand, an illustrated essay on sand, driftwood and the beach repair mechanism. (3 pages)
A log of recent changes to this section (on this page)
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Beaches studiedIn my search to answer the question why we are losing so much of our marine environment, I noticed that we are also losing our beaches. Contrary to engineers' reassurances that our beaches are "in a stable dynamic equilibrium", I discovered that many are not. Here in New Zealand we are able to find beaches in all states of health, mainly because this is still such a young country with so few inhabitants, having been developed only a hundred years ago. Elsewhere in the world, most beaches appear to have proceeded past their 'point of no return', which has led scientists to believe that beach erosion is an unavoidable world-wide problem.

My search led me to many beaches in northern New Zealand (see map) and encouraged me to study the situation elsewhere in the world. Scientists and engineers world wide are treating the beach/dune system as a balance where sand is shifted between the various compartments. This method is not able to qualify whether a beach is healthy or not. A breakthrough came when I likened a beach to a living organism, a comparison justifiable by their similarities. A self repair mechanism is the most important mechanism in any living organism and also for the beach. If it is absent, the beach and dunes will die. If it is healthy, the beach and dunes react to changing circumstances in a way necessary to survive.

My findings are based on simple observations, backed by simple physics that are valid all over the world. Instead of awaiting the result of decades of measuring and monitoring, the health of a beach can now be assessed in as little as a single visit. By understanding how the beach self repair mechanism works, we can now understand why many human activities are so disastrous for a beach's health. But do we have the strength to remove coastal trees, bulldoze dunes and do things opposite to what was once thought right? It sure is an enormous challenge for society. The good news is that many beaches can still be saved, now that we know what damages them.

In the course of this beach study I have also attempted to formulate a number of physical laws that govern the formation of beaches and dunes. They enable one to make generalisations and predictions and to understand the various types of beach. They also polarise thought while facilitating education. These laws need to be tested further for their generality.

By means of this writing, I am also challenging the scientific community to take careful notice of my findings and theories and to attempt to prove me either right or wrong. Obviously a lot more research needs to be done. The underlying issues are far too important to ignore. Could it be true that we have overlooked something important? I think we have! Are we perhaps the architects of our own problems? On a more positive note, my findings could provide a treasure trove of work for dissertations, papers and publications.

By putting my findings on Internet where it can be accessed world-wide, I hope that readers will take notice so that many beaches can still be saved or restored. I have attempted to separate my own work from what is generally accepted as common knowledge and the reader is often referred to related chapters in the section Oceanography, particularly the chapter on dunes and beaches. The text is written in an unscientific way, freely using terms such as sick, healthy, dead, to make it easy to understand.

Dr Floor Anthoni,
November 1999.
E-mail me for suggestions and correction.


More reading
Books printed in blue are available from the Seafriends Library.

Auckland Regional Council reports:
  Beach monitoring report for Long Bay, Muriwai and Piha. Tonkin & Taylor Ltd. 1998
  Omaha beach profile data base. Tonkin & Taylor Ltd. 1998.
  Wave buoy deployment at the Mokohinau Islands: Data report. NIWA. 1999
Bascom, Willard: The crest of the wave, adventures in oceanography. 1988
Bramwell, Martyn (ed): Atlas of the oceans. 1977. Mitchell Beazley Publ.
Carter, R W G: Coastal environments - an introduction to the physical, ecological and cultural systems of coastlines. 1989, 1991. Academic Press. 
Coleman, David C et al: Fundamentals of soil ecology. 1996
Cowen, Robert C: Frontiers of the sea: the story of oceanographic exploration. 1960. Victor Gollancz Ltd.
Dean, Cornelia. Against the tide, the battle for America’s beaches.1999.
Harris, T F W: North Cape to East Cape, aspects of the physical oceanography. 1985
Harris, T F W: Hauraki Gulf tideways, elements of their natural sciences.1993
Kaufman, Wallace & Orrin H Pilkey Jr: The beaches are moving, the drowning of America’s shoreline. 1998
Montgomery, Carla W: Environmental geology. 1997
Morton, John and David Thom, Ron Locker: Seacoasts in the seventies, the future of the New Zealand shoreline. 1973.  Hodder & Stoughton.
Pilkey, Orrin H and Katharine L Dixon: The Corps and the shore.1996. Island Press. Examining the failures in coastal engineering done by the Army Corps of Engineers in the USA.
Van Dorn, William G: Oceanography and seamanship. 1974
Vetter, Richard V, editor: Oceanography, the last frontier. 1974. Forum Series.
Villiers, Marq de and Sheila Hirtle: A dune adrift; the strange origins and curious history of Sable Island. 1940,2004. McClelland & Stewart. A mysterious long dune island exists far out in sea off the coast of east Canada. How could it exist?


What's new?
20071016 - A beachcare group in SE Australia vindicates our remedy to save beaches: remove all planted vegetation.
20051210 - Minor changes and book list expanded.
20030218 - Beach drainage expanded with the Hirtshals discovery and links to research institutes.
20010809 - Ice age movement of sand dunes adding another argument against that of rising sea levels causing beach erosion.
20010610 - Mining the sea sand, a case study in New Zealand, added.
20010525 - More emphasis on beach sand pollution. Predicting no dunes ever formed around large river mouths.
20010409 - Shells on beaches added and kicking the sand to detect pollution from fine mud particles. A summary on missing knowledge added. Various amendments and improvements to all chapters.
20010223 - The evolutionary viewpoint added to dune vegetation succession. The sedimentation/transportation diagram added to the chapter on the beach's self repair mechanism.
20000819 - Driftwood added and an essay by Michael Smithers about sand, driftwood and dune formation.
20000601 - More about Artifical Surfing Reefs and observations at Narrowneck Beach. More about headlands.
20000331 - Corrections & suggestions from Mrs Myfanwy Borich applied. New subchapters The line in the sand. and Mining the sea sand. New photos and maps.
20000320 - Started to put this important issue on Internet.

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