Flooding of the Olifants River in the last week of January raised concerns about the effect that the raising of the Massingir dam wall in Mozambique is having on the Olifants gorge in Kruger, as this is the first flood since the wall was raised. The last point of measure in the Olifants River before it leaves South Africa is at the Mamba weir in the Kruger National Park (KNP). This weir is near the Phalaborwa barrage, which supplies water to the town of Phalaborwa.
On January 26, 2008 the river flow recorded through the Mamba gauging weir was 1250 cumecs. This was the peak flow recorded, and although the water level remained high for the next two days, on January 29 the recorded flow had almost halved to 680 cumecs. The water level fell rapidly, and on February 2, 300 cumecs passed over the gauging weir. Almost a month later, on February 20, the flow had dropped to 120 cumecs. Last January the flow in the Olifants River never topped 120 cumecs, even at peak flow.
Steven Whitfield, the Tshokwane section ranger, and Rendani Nethengwe, section ranger Houtboschrand, flew the Olifants Gorge in the Bantam ultralight aircraft on the morning of February 2, 2008.They climbed to a height of 3500ft and were directly above where the Olifants leaves South Africa into Mozambique. “The purpose of climbing to this height was to be able to get a wider view of the Olifants gorge as well as the Massingir dam at the same time,” says Steven.
“After taking numerous photos of the Olifants gorge as well as the dam, but remaining in the same position we gradually descended whilst still taking photos to a height of approximately 100ft above ground level and then worked our way upstream along the Olifants River.” They noted large areas at the top end of the dam in Mozambique where groves of trees were seen standing in the water, indicating that these were now flooded for the first time.The water pushed back into the Olifants Gorge as far back as Bangu mouth – the water seemingly standing still and calm.
From the Mozambican boundary upstream to just below Bangu mouth in the Park, there were no sand banks visible. The only sand banks seen were far away from what would have been the previous normal flow of the river and “most probably sand deposited during times of extreme floods such as cyclones Emily, Demoyna and the 2000 floods.”
The gorge was well known in the past for its thriving crocodile population, with exceptionally large individuals. Steven says the only crocodiles seen in the now-flooded area of the gorge were those in the water. As they flew upstream above the flooded part of the gorge, sightings of crocodiles in the water increased dramatically, “with an abundance of crocodiles also being seen on the sand banks.”
“In the flooded part of the gorge there was also a total absence of hippos obviously brought about by the deep water.”