Weekend rains do little for drought-stricken dams
There has been little impact on the levels of major dams.
THE cold front which brought a deluge of torrential rain with it has done little to alleviate the plight of many of the province’s drought-stricken dams.
Many Durban residents had hoped the rain of the past 48 hours would put a huge dent in the low levels of KZN’s parched dams.
According to Shami Harichunder, corporate stakeholder manager at Umgeni Water, their operational area recorded moderate to good rainfall over the past 48 hours. However, at this stage there has been little impact on the levels of major dams.
“There has to be a similar amount of rainfall for at least three days before a significant difference is seen in the levels of large dams, including Hazelmere in the north of Durban,” said Harichunder.
“At Midmar Dam 48,8mm of rainfall was recorded while at Spring Grove Dam 35,7mm fell and at Mearns Dam 32,6 mm was recorded. Water in Mearns and Spring Grove dams are used to augment water resources in Midmar Dam through transfers,” he added.
After an update, the level of Midmar Dam remained at 45%, while Mearns Dam, Moor River was at 50% and 6% since Friday, 22 July. “At this stage, the rainfall received has had the effect of stabilising Midmar Dam at 45%. There are three factors that could possibly explain the unchanged level of Midmar Dam at this stage. This is a large dam and if rain run-off has made its way into the dam, the amount would be small and, therefore, no noticeable difference would be seen. Much of the rain already received has been absorbed into parched ground, consequently, there was no or little run-off into the dam through the river feeder system,” he said.
He added that it takes at least 48 hours for the bulk of run-off to make its way into a dam. It is estimated that on average between 10% and 20% of rain makes its way into a river system. Therefore, a clearer picture of the impact of rainfall on the level of Midmar Dam will emerge in 48 hours,” added Harichunder.
In the mid-South Coast, 79mm of rainfall was received at Umzinto and EJ Smith dams over the past 48 hours, while at Nungwane Dam, 40mm of rain was recorded in the same period.
The rains have had the effect of increasing the level of Umzinto Dam by 18,58% since Friday. Today (Tuesday, 26 July), Umzinto Dam was at 88% and Nungwane Dam was at 89% – up 8% since Friday. EJ Smith Dam was at 98%, a slight increase of 9%. “If rains continue on the South Coast, Umzinto, Nungwane and EJ Smith dams will begin overflowing as these, like Mearns and Spring Grove dams, are small dams that fill rapidly,” he said.
The level of Ixopo Dam remained unchanged at 50,27% on 26 July. This dam is being supported by water transfer through an emergency scheme.
Rainfall recorded at other Umgeni Water dams over the past 48 hours:
- Nagle Dam: 54,2mm
- Inanda Dam: 57,0mm
- Albert Falls Dam: 49,2mm, and
- Hazelmere Dam: 43,5mm (this dam has risen by 1% over the past 48 hours)
