Coast KZN

22 Oct 2016

Copy nature to fight beach erosion

Jean Simonis (Zululand Observer)

Sodwana beach dunes stabilised with vegetation

Can we find a simple solution to this complex problem?

What has happened to our beaches, the long sloping beaches where our kids used to run, eat dripping ice cream and paddle in gentle waves?

The receding beach is telling a story of complex forces at play, forces that are changing our beloved landscapes.

How has this impacted the loss of Alkantstrand’s Blue Flag status or the potential on tourism and recreation?

Can we find a simple solution to this complex problem?

One simple truth one must accept is that nature is central to life and that knowledge of its processes can provide simple solutions to apparently difficult problems.

A case in point is the recent coastal erosion experienced at Alkantstrand that resulted from stormy seas and extreme tides.

The Dutch have been battling just such seas and its strength for hundreds of years.

Their protection has been a natural or man-made grassy dune providing the defence of the country.

Where no natural dunes existed, the Dutch built a three-fold dune equivalent. The first, facing the sea, is the ‘guardian’ (Afrikaans- wagter), the second the ‘sleeper’ (slaper) and third the ‘dreamer’ (dromer).

Nature’s gift
This incredible engineering method defending their whole country from a watery invasion was designed according to nature’s own gift – the dune (Mcharg, 1992).

Could such a little sand hill that saved the Netherlands be the solution for Richards Bay’s beach erosion?

Many researchers and coastal engineers speak about ‘flexible (soft) construction’ as a solution to the approximately 350km of the KZN coastline subjected to severe erosion.

In the Netherlands this information is already preached at pre-school level, whereas elsewhere in the world and in RSA it will not be found in engineering manuals where hard (inflexible) solutions are the norm.

Such defences accept the full brunt of the waves and collapse through undercutting (UNESCO, 2010).

Compare this with Dutch thinking that accepts that the sea cannot be stopped, but only directed by reducing the velocity and absorbing its forces by using nature’s flexible vegetated dune.

If they have been able to contain the sea for hundreds of years, can we do the same by designing with nature at Richards Bay?

In the following weeks we will be discussing the complex processes involved in the shaping of our coastline.

We will look at both national and international successes and failures and in the process propose natural solutions to a process that has been happening for millions of years.

• Simonis is a professor at the University of Zululand’s hydrology department
Sources: Mcharg, IL., 1992. Design with nature, John Wiley & Sons, NY.
UNESCO, 2010. Sea-level Rise and Variability: A summary for policy makers, Intergovernmental Oceanographic Commission


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