Anton Kruger’s letter, Lagoon ‘not a simple matter’ (The Village NEWS, 29 May) refers.

Whale Coast Conservation is pleased to associate itself with the excellent work that is being done by members of the Onrus River Estuary Forum (OREF), under the chairmanship of Dr Peter van Niekerk.

An OREF-initiated process is well underway to draw up a formal recreational health management protocol for the Onrus River Estuary (lagoon), in which the Overberg District Municipality (ODM), Overstrand Municipality (OM), Breede-Gouritz Catchment Management Agency (BGCMA) and the OREF will be participants. The protocol will be the first documented commitment by government agencies to implement formalised, systematic management of recreational water quality for any of the estuaries in the Overstrand.

The protocol deals with the how, when, by whom, with what resources, and according to what standards:

  1. The estuary’s recreational health status will be decided, based upon the outcomes of sanitary surveys and bacteriological data;
  2. The recreational water quality will be monitored;
  3. High bacteriological test results will be responded to;
  4. The risk of using the estuary for recreational purposes will be communicated to the public;
  5. The protocol will be reviewed and improved upon.

The finalisation of this protocol is a high priority for the OREF executive team, members of which are assisting and working closely with officials from the ODM and OM who have taken responsibility for developing the protocol and having it officially approved.

Contrary to what is being claimed in the letter by Mr Kruger, Dr van Niekerk is not proposing to reclassify the Onrus Estuary as a “fresh water dominated system”. Data collected from testing 37 fortnightly water samples has shown the salinity level to be around 7% (and less) of the salinity of the sea. Data does not support the claim that there are “high spikes in salinity”.

The laboratory data clearly shows that the system is fresh water dominated. Using the Department of Environmental Affairs (DEA) marine water standard, applicable to water with seawater salinity, to determine the recreational health status of the estuary’s water is therefore inappropriate; the standards contained in guidelines from the Department of Water and Sanitation (DWS) for freshwater systems are more appropriate.

Decisions on whether the water quality of the Onrus estuary is suitable for contact recreational activities have to be made on the basis of actual data and comparing this with an appropriate standard. Reliable data exists for the past 37 fortnights and comparison of the data with the DWS guideline indicates that the recreational water quality during that period can be regarded as at least satisfactory.

This does not mean that OREF or the local and district municipalities can stop focusing on the need to improve the background water quality and to ensure the necessary response to occasional high bacteriological test results; the protocol under development will ensure that continuous improvement becomes institutionalised. The work of Dr van Niekerk and his team to date, however, provides the reassurance that recreational activities historically enjoyed by residents and visitors can continue in the estuary without people incurring undue health risks.  

We must always remember that this is a natural system, subject to both natural and anthropological processes and influences. We take risks from breathing in airborne pathogens and occasionally succumb to these; there will always be a level of risk in swimming in any estuary or other naturally occurring body of water, anywhere in the world. There will always be an element of risk when we swim in the Onrus Estuary. The data shows, however, that this risk has, on average, been acceptable, by DWS standards, for the past 37 fortnights.  

Onrus recreational water quality is acceptable on average… anybody for a swim? But, brrrr… it’s winter! Whether you decide to take a dip now or not, be careful you don’t catch the flu from the air you breathe or the shopping trolley you push, because the probability of contracting that is far greater than getting gastro infection from swimming in the Onrus Estuary!

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