Saving the embattled Estuaries by Tony Carnie.
28 October 2009 article from The Mercury newspaper.
A Mozambique tilapia with unhealed mouth ulcers caused
It really comes as no surprise that most of the river estuaries in Durban are sick or dying - fouled by sewage, starved of clean water or torn apart to satisfy the relentless hunger of the building and construction industry. There are now more than 3.5 million people living in the municipal boundaries of South Africa's second-largest industrial and manufacturing centre. And the law of gravity dictates that a sizeable volume of waste from this vast metropolis will eventually flow downhill to the place where the land meets the sea.
This interface zone is neither land nor sea. It is neither fresh river nor salty sea water, but a mixture that fluctuates according to the seasons or the time of day. And as the colder and fast-flowing rivers approach the vast road-block of the Indian Ocean, they are forced to slow down and drop their heavy loads of mud and sand or the nutrients from plants, animals and humanity. The muddy river bottoms are home to a vast range of tiny nunus Because they are neither river nor sea, the chemistry and temperature in estuaries is also unique. In some ways, estuaries can be compared to natural soup bowls, fed by a rich broth of food and nutrients - all of which combine to give birth to a more abundant and wider variety of life. The muddy river bottoms are home to a vast range of tiny nunus, worms and swimming prawns that cascade to form a tasty food web for fish, crabs, birds, animals and humans.
Surely it is no accident that 22 of the 37 largest cities in the world are located on estuaries.
Quite apart from the abundance of food, there is fresh water close by to turn and to cool the wheels of industry. And once the wheels have turned to produce anything from steel, sugar or corn flakes, the biggest river mouths provide perfect places to shelter the ships of commerce as they are loaded and unloaded for new voyages.Not surprisingly, several types of fish also take shelter here from time to time to breed, lay their eggs or simply to fatten up.
'The present state and condition of estuaries in eThekwini is cause for serious concern'
It all sounds rather idyllic.
But there comes a point when the natural balance of these unique and constantly changing environments is overturned and thrown completely out of balance.
Indeed, estuary fundi George Begg came to a similar conclusion nearly 30 years ago, while previous researchers sounded warning bells in the late 1940s.
In painstaking detail, two of the country's most prominent estuarine scientists have consolidated the historical data on the 16 river mouth areas along a 97km stretch from Tongaat to Umzinto, and added volumes of up-to-date information on current river health. They have measured sewage bacteria, salinity, temperatures and oxygen levels, counted the number of tiny swimming prawns lurking in the mud, the types and number of fish and birds, the depths and types of mud and sand and the plants that protect or degrade river banks. They lament the fact that the first warning signals have largely been ignored for half a century by previous municipal custodians and that current Department of Minerals and Energy officials have shown an "unacceptable" level of indifference to the damage caused by sand-mining operators.
But rather than dwelling on the past unduly, they have delineated new borderlines for the 16 estuaries and recommended an ambitious programme to restore, protect and preserve these degraded city assets. They recognise that the pressure for new development in the floodplains and catchments will increase further, but suggest it is vital for the city's decision-makers to start reversing the legacy of neglect and destruction. Rather than trying to engineer a way out of the problems, Forbes and Demetriades say the challenge is to turn around the generally accepted viewpoint that further degradation of estuaries is a "normal" and "acceptable" consequence of economic development.
"In many cases, there is still time to turn things around in the estuaries of the municipal area."
But this will require strong political will, innovative thinking and proper resources.
"It is, however, an essential step to take to prevent Durban's estuaries degenerating to the point where they simply become conduits conveying refuse and wastes to the sea."