Neels Blom Writer at large

As the water and sanitation crisis on the Vaal River and its catchment escalates, two government departments have issued a joint statement denying a positive link between mass fish mortality and raw sewage flowing into the river.

Reports over the past weeks have shown fish kills as evidence of sewage discharge into tributaries on the north bank of the Vaal River, and linked that to health risks to millions of people and a constraint to development.

The presence of excessive levels of E.coli in the river is linked to disease outbreaks in especially poorer communities and threatens the phytosanitary status of export farmers who irrigate from the river.

This means the demand for clean water to dilute polluted water downstream rises in relation to pollution levels.

Clean water is supplied by the Lesotho Highlands Water Project into the Vaal River upstream from the Vaal Dam, where Gauteng’s drinking water is abstracted for distribution by Rand Water.

About 60% of SA’s economy is dependent on this supply.

Downstream pollution

In one of the department of water & sanitation’s own water-quality management documents, the department acknowledges that downstream pollution equally affects upstream abstraction.

"[Pollution] increases the costs of doing business such that many enterprises are forced to treat water … [and] the cost of municipal water treatment increases. It reduces productivity as more work days are lost due to water-related illnesses and … threatens several economic sectors."

However, last week’s statement, issued by the department of water & sanitation as well as the department of agriculture, forestry & fisheries, suggests the fish kills may have been related to a "drastic drop in temperature" leading to lower oxygen levels in the water — although it is well-established that dissolved oxygen levels are higher in cooler water and that fish kills at this extent are widely attributed to high pollution levels, as reflected in a paper by the freshwater research unit at the University of Cape Town.

The statement also said preliminary investigations in mid-July had found no dead fish at an "alleged" site, but an inspection of the mid-Vaal section of the river from Vereeniging in the east to Parys in the west by Business Day at the weekend showed scores of dead and dying fish drifting in the current at each of four points about 10km apart.

The department of water & sanitation has only 35 compliance and enforcement officials for the whole country, according to the SA Water Caucus.

At an upmarket property development outside Parys about a dozen dead fish floated past a marker on the south bank within 20 minutes.

Over the same period, dozens more distressed fish broke surface. Similar kills were evident below and above the Barrage at Vanderbijlpark and at Three Rivers near Vereeniging.

The inspection confirmed reports of extensive sewage spills in farming areas and wetlands. Several civil society groups have identified the cause as failed infrastructure, and the Save the Vaal Environment has won a court order against the council, directing it to remedy the situation.

But the council has admitted that it is unable to comply and confirmed that it had been placed under partial financial administration of the Gauteng provincial government.

The department of water & sanitation did not respond to queries for comment.