More dams needed to aid Crocodile River System
A new dam is vital for the future of the Lowveld's water supply, but it will still only result in a fraction of the Crocodile River's potential run-off. An expert said the area will need numerous dams to keep up with the growing demand.
According to a study done by the Crocodile Major Irrigation Board, only 15,5% of the mean annual run-off (excess water flowing into rivers and streams) is currently stored in major dams in the Crocodile system. The proposed construction of a new dam at the Mountain View site will increase that number by 16,4%, to 31,9%.
“The Crocodile River is severely disadvantaged in comparison to other catchments, like the Olifants River,” said Walter Visser, chairperson of the Crocodile Major Irrigation Board. “In fact, we need numerous dams to compare to the 73,4% of the mean annual run-off stored in dams in the Olifants system. I don’t think we will ever catch up.”
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Currently, a total of 169 million cubic metres of water are stored in major dams in the Crocodile system, while the mean annual run-off in the catchment, or the catchment potential, reaches around 1,093 million cubic metres. The proposed dam at Mountain View, located in the Kaap River system, will have an estimated storage capacity of 180 million cubic metres. “We would need to have about 802 million cubic metres storage capacity to store 73,4% of the annual run-off, which is 622 million cubic metres more than what is stored currently,” Visser added. If serious attention is not paid to the growing demand of the water supply in the Lowveld, the prediction is that more severe restrictions will be placed not only on irrigators, but all users.
“Within the sugar cane producing areas, yield losses are experienced, while growers also experience losses when cane becomes so water-stressed that the quality delivered to the mill is sometimes so low that it is rejected,” Visser said. The long-term effects will be detrimental to lower-value crops. “The acute water shortage leads to the available water allocated to the high-value, long-term crops,” Visser added. “This has resulted in huge areas lost to cane supply in the Malalane area.” Water supply, especially for irrigators, is most crucial when the water supply system is most stressed and the dams normally at their lowest levels. “It has to be realised that the water demand for citrus and other tree crops is the highest in the dry period after winter before the summer rainfall period starts, when the temperatures rise and the crop water demand increases,” said Visser. “This is also the most critical period to ensure that tree crops are not stressed, when fruit set is taking place.” Visser concluded by saying government needs only to look at these numbers to realise the severity of the water crisis in the area. “I don’t think there is a lack of funds to construct the necessary dams. I think government just does not have the will to take on this crisis, while also having no regard for the lost opportunity in economic growth.”
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