The Jukskei River flows into the Crocodile River and into the Hartbeespoort Dam. Picture: Thobile Mathonsi

Pretoria - Water in the Hartbeespoort Dam will reach unacceptable levels of pollution in a few years if nothing is done as a matter of urgency.

The famous tourist destination located on the western outskirts of Pretoria will subsequently risk losits global standing owing to the pollution that is tainting the dam.

The dam has yet again experienced a massive sewage spill which originated from the Northern Works Waste Water Treatment Plant, situated near the Fourways/Diepsloot areas in Joburg north.

Late last week, the plant released millions of litres of untreated sewage into the Jukskei River.

The sewage spills fed into the Jukskei River, which links up with the Crocodile River and then flows into the Hartbeespoort Dam.

In addition to the spillages from Northern Works, more pollution emanating from pump stations, manholes and sewage plants, entered the river.

This dirty water also ends up in the Hartbeespoort Dam after the rain and flood events of the past few days.

This is according to Petrus Venter, regional director in the North West Department of Water Affairs in charge of water quality management.

“The two have happened concurrently which worsened the situation. There is an impact coming to the dam from pump stations and sewer spillages which we can also see at Centurion Lake,” Venter said.

“And with the first summer rains which have brought those spillages into the dam, there was the spill from Northern Works which has worsened the whole situation.”

He explained that every time it rained, pollution flooded into the rivers from storm water drains, manholes and other tributaries.

Venter said that if nothing was done about the pollution, algae and hyacinth would build up, resulting in unacceptable conditions which plagued the dam some 10 years ago.

In 2006, the Department of Water Affairs started a programme called Metsi a Me (My water) to rehabilitate the Hartbeespoort Dam.

The dam up to that point had been clogged by hyacinths and polluted with extensive algae growth and litter.

According to a civil engineering journal, during its heyday the programme employed between 80 and 140 workers and removed at least 64 000m² of hyacinths, 2 400 tons of litter and debris and 31 million litres of algae soup. Algae mass is not only unsightly, but decaying material tends to emit a foul odour, in addition to producing potent hepatotoxins, a toxic chemical that damages the dam.

The algae also grows over the entire surface area of the dam.

Hyacinths have a higher nuisance value in terms of their coverage of the water surface and the limitations their growth places on recreational activities on the dam.

The programme was shut down this year, leaving the dam vulnerable and at risk of reverting back to its hypertrophic state. This means that during this time the dam had excessive nutrients which would deplete the water of oxygen.

During an inspection of some parts of the dam on Monday, algae could clearly be seen in both the Jukskei and Crocodile rivers. Hyacinth is also very clearly visible in large parts of the dam.

There were parts of the sewage spill that was also visible. However, Venter explained that the sewage sank to the bottom of the dam, but left a grey colour in the water, which was also visible.

The dam is home to many boating and jet ski companies which offer boat cruises and rides to the public, including tourists.

With the dam filling up with pollution, in the long term the businesses in the area arew bound to be affected.

Joburg Water could not be reached for comment at the time of going to press, but had earlier told EWN that plans were in place to reduce operational failures in future at the waterworks.

Hartbeespoort Dam, also known as Harties, is an arch-type dam and lies in a valley south of the Magaliesberg mountain range and north of the Witwatersberg mountain range.

The dam was originally designed for irrigation, as well as domestic and industrial use.

The construction of the dam started in August 1916. Initially work was delayed pending a court judgment with General Hendrik Schoeman and a certain Mr Marshevin about the expropriation of their properties.

The dispute was later resolved but discontent remained after a hastily passed law to facilitate the expropriation.

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