By Lloyd Phillips
After many weeks of heavy rains in its approximately 7 814km2 catchment, northern Zululand’s renowned Pongolapoort (Jozini) Dam is expected to start overflowing uncontrollably, potentially putting downstream farmers and other residents in danger.
When northern Zululand’s Pongolapoort Dam starts overflowing either during Thursday or by Friday morning latest, the volume of uncontrolled water flowing downstream will be sufficient to fill an Olympic-sized swimming pool every 7,5 to 12,5 seconds.
The Department of Water and Sanitation has issued warnings to all residents along the Phongolo River that continues downstream of the Pongolapoort Dam to be on high alert for sudden flooding from uncontrolled overflow. The Pongolapoort Dam is reportedly South Africa’s fifth largest dam by volume.
Large-scale farmers in that area that spoke to African Farming, say they are primarily concerned for the safety of the numerous small-scale farmers downstream of the dam. Many of these latter farmers are in the low-lying Makhathini Flats area where they produce livestock, sugarcane and cotton.
Riaan Heystek, one of the large-scale farmers, says of particular concern is that many of the small-scale farmers and other residents downstream of the dam, farm and/or live within the Phongola River’s floodplain.
Another large-scale farmer, Kurt Stock, says the Phongola River upstream of the dam has already flooded low-lying roads and bridges. He adds that, according to his calculations, the Pongolapoort Dam is likely to start overflowing uncontrollably sometime on Thursday.
This is echoed by large-scale farmer Dreyer Senekal, who says on Wednesday this dam, whoch can hold approximately 2,5 billion cubic meters of water, was 98,57% full. At the same time, water inflow into the dam was averaging 172,32 m3/second. However, by Thursday morning the water inflow had surged dramatically to 339,9 m3/second, and the dam was at 99,61% of its capacity.
“It’s a hang of a lot of water that’s coming into the dam,” says Senekal.c“It’s going to be spectacular when it overflows.”
Construction of the Pongolapoort Dam wall was completed in 1973. It reportedly stands 89 metres high above its lowest foundation, and its crest length is 515 metres. The publicly accessible Jozini-KwaNgwanase road travels over the top of the dam wall.
