Durban - An integrated harbour water quality management plan has been proposed to manage the sensitive marine ecosystem in eThekwini in a sustainable manner.

The municipality's City Manager Dr Michael Sutcliffe has proposed the notion in response to the recent "fish kill" incident in the Durban harbour.

According to Durban media reports hundreds of dead fish were found in Durban Harbour, on Sunday, for the second time in a month.

The reports claimed that there was foam in the water and suggested that detergents had been used to disperse oil pollution in the harbour.

Mr Sutcliffe indicated that there are a number of potential factors which could have led to the incident, including waste management practices within the port and in the catchment draining into the port.

"The recent spate of rains could have contributed a greater organic load into this system and the fact that there could be industrial effluent discharges being illegally connected into the storm water system," said Dr Sutcliffe.

eThekwini Water and Sanitation Deputy Head, Frank Stevens said the assertion that raw sewage spilled into the Umhlatuzana River was investigated.

Mr Stevens reported that prior to the incident, there had been a sewage overflow into the Umhlatuzana River catchment due to a partial pipe blockage.

However, he noted that chemical oxygen demand measurement taken downstream of the spill proved that the levels were well below those which would be harmful to fish.

"The blockage was attended to as soon as it was brought to the notice of our Operations Staff.

"As much as the media would have liked the exact source that contributed to the fish kill pinpointed, our investigations to date shows there is no unique association. The investigations are ongoing," said Mr Stevens.

He further said the team that has been working on the incident has gone beyond normalising the situation to the point where attention will now be focused on how they work towards preventing further fish kills.

This will be achieved by the implementation of an estuary management plan, he said.

He said the general view was that there were a multiplicity of interacting factors that led to the state of de-oxygenation in the harbour estuarine water quality that caused the fish kill.

"There is no organisation or source that could be solely held responsible, this type of fish kill is known to have occurred in other parts of the world due to processes of urbanisation and development.

"There could be a combination of naturally and anthropogenically induced factors, we need to develop a better understanding of this sensitive ecosystem," said Mr Stevens.

He added that a vigorous system of monitoring, surveillance and reporting and an early warning system was required to prevent such fish kill in the future.

"Regular monitoring will also give us a better understanding of how the complex harbour and land-use systems interact and what are effective means of intervention.

"All of this will be incorporated into an integrated estuary management plan,' said Mr Stevens.

The key institutional and technical elements of the Estuary Water Quality Management Plan will include an assessment of all inputs in to the bay, the development of monitoring and measuring protocols and reporting thereof, the development of emergency preparedness plans and regular communication to the media and the multi-stakeholder forum.

The plan will also entail institutional, technical and social elements. - BuaNews

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