By Emma Kakololo
The rehabilitation of Goreangab Dam would require a combination of national and local legislation, as well as a concerted effort to prevent any raw sewerage or sewage effluent or untreated storm water from entering the dam, the City of Windhoek said recently.
The dam was built in 1958 with a capacity of 3.6 Mm3 (~951 MG).
The City of Windhoek’s Manager Corporate Communication and Tourism, Ndangi Katoma, said on Tuesday that the cost of rehabilitating the dam might be more than N$1 million, but the daunting task would be to keep the dam free of future contamination.
After rehabilitation, the potential selling value of the water in the dam, as drinking water, is estimated at a mere N$5 million.
“High alkalinity and high organic content, are two parameters which contribute to high treatment costs,” he said.
“The challenge is that it will be possibly polluted again with the next sewer blockage or rainy season. There is no easy solution to this.”
According to Katoma, all the municipality can do is to put up signs to warn people of the dangers of using the dam, but this would need strict enforcement mechanisms for people to respond.
“Protecting the public or keeping them (public) away from the dam is difficult.
To fence off the entire dam will be a futile exercise, as the fence will be vandalised. The city has provided warning signs in order to protect people but it remains the responsibility of an individual to adhere to the signs.”
He said the city is analyzing the dam regularly and could confirm that the water was not suitable for human consumption or else economically feasible to purify.
“The dam is heavily polluted from all kinds of sources, mainly of domestic origin such as wastewater from sewer breakages and overflows. Thus bacteria and viruses are present and therefore from around 1992/1993 all sporting or recreational activities like boating were prohibited.”
However, he noted that the area surrounding the dam was still safe for picnickers provided that they do not come into contact with water.
With regard to eating fish from the dam, he said: “Although when fish are cleaned and cooked properly, the viruses and bacteria may be destroyed, it may be relatively safe to eat fish. However, shellfish concentrate viruses. Therefore, so many people get sick from eating shellfish, although we do not have statistics at this stage.”