UMGENI Water’s largest system which supplies water to an estimated four million consumers in uMgungundlovu District, Pietermaritzburg and much of eThekwini remains under stress as the drought continues its firm grip on KwaZulu-Natal.
The system in question, Mgeni, comprises, in its upper part, Mearns Weir, Spring Grove Dam and Midmar Dam.
The lower part of Mgeni system comprises Albert Falls Dam, Nagle Dam and Inanda Dam.
The levels of four of these dams are lower than they had been a year ago while the levels of the remaining two are marginally higher than they were a year ago to the day.
The levels of these dams as at Monday, 9 January, are shown on the left while their levels a year ago are in brackets:
57% Midmar: (48%)
108% Mearns Weir: (71%)
51% Spring Grove: (74%)
60% Nagle: (86%)
27% Albert Falls: (38%)
62% Inanda: (81%)
“Spring Grove and Mearns are small dams that empty out as quickly as they fill up. Mearns is currently overflowing as a result of good rains in its catchment, which are Mooi River and the Drakensberg.
“Water from Mearns Weir ultimately makes its way into Thukela River. Rainfall received in Pietermaritzburg and surrounds during the weekend of 5th to 8th January 2017 had no impact on the levels of Midmar, Nagle and Albert Falls dams as it fell outside of the catchments of these dams,” said Shami Harichunder, corporate stakeholder manager, Umgeni Water.
Water scarcity in Mgeni system has been as a result of a prolonged period of below-average rainfall in the major catchments, culminating in the major dams, Midmar and Albert Falls, being at low levels.
Midmar Dam has been stabilised at mid-50 per cent as a result of transfer of water into it from Spring Grove Dam, as well as some rainfall.
“Of great concern to Umgeni Water is the level of Albert Falls, the largest dam in Umgeni Water’s operational area. Water is normally transferred into Albert Falls from Midmar, but application of this rule has had to be stopped because of inadequate water in Midmar.”
He said declining water levels in Mgeni system has forced Umgeni Water to reduce by 15 per cent production of potable water at Midmar Water Treatment Works, DV Harris Water Works, Durban Heights Water Works and Wiggins Water Works and to also implement water rationing.
Water rationing and restrictions were implemented as a strategy to prevent possible failure of Midmar and Albert Falls dams.
“Mandatory water restrictions of 15 per cent have also been implemented in uMgungundlovu, Pietermaritzburg and greater Durban – the areas that receive water from these water treatment works,” he said.
Umgeni Water has issued a reminder to all consumers that water restrictions still remain in place in all of uMgungundlovu, Pietermaritzburg and in about 80 per cent of Durban.
An appeal has also been made to consumers to use water sparingly.
Areas of Durban not affected by water restrictions are in the far north of the city. These areas are supplied by Hazelmere Water Treatment Works.
Conserve water
Failure of dams would have had dire consequences for the economies of Pietermaritzburg and Durban according to Shami Harichunder, corporate stakeholder manager, Umgeni Water.
“Failure occurs when a dam dries up, leaving only silt in it. Failure of these dams has been mitigated by the application of restrictions, reduction in potable water production and water rationing.
“In October and November 2016 an estimated total 1 000mm rainfall was received in the entire Mgeni system. This is on par with the 20-year average for October and November. However, rainfall received collectively in 2016, in 2015 and part of 2014 remains in a deficit state – which means that the amount is far less than the average annual rainfall.
“In order for the situation to return to a state of normality – and major dams to begin rising significantly – at least two seasons of above-average rainfall are required. Midmar and Albert Falls dams will have to reach levels of 70 per cent each before the resource in them could be considered to be adequate to meet the full needs of uMgungundlovu District Municipality, Msunduzi Local Municipality and eThekwini Metro,” explained Harichunder.
Forecasts by South African Weather Service and the Council for Scientific and Industrial Research suggest that if above-average rainfall is received, this is only likely to occur in the first quarter of 2017.
This means that the amount of water available in Mgeni system will have to last until the next rains. Thus far, in the first days of 2017, little rainfall has been received.
“If the predictions of above-average rainfall do not materialise, the multi-stakeholder Joint Operations Committee for Mgeni system may have to consider requesting the Department of Water and Sanitation to increase mandatory restrictions, from its current 15 per cent to, say 20 per cent or 25 per cent.
“This measure will only become necessary if good rains are not received. Adding to the current complex situation is prevailing high temperatures that cause evaporation of dam surface water.
“It is, therefore, imperative that disciplined use of water and strict adherence to the current restrictions continue. By practising water conservation consumers will assist in ensuring that some of it will be available for future consumption and until the next rains are received,” stated Harichunder.
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