Water woes in KZN — Umgeni Water gives us a rundown

A contractor has been appointed to begin repair work on two large pipelines that transfer raw water from Nagle Dam to the Durban Heights water treatment plant for the treatment and supply of potable water to eThekwini Metro.

The next steps after the appointment of the contractor are to establish a site from where work will be managed and provide a detailed project implementation plan to Umgeni Water.

Two pipelines were extensively damaged in the April floods and this occurred in Wushini, Inanda, Durban. These two pipelines and two others transport raw water to the Durban Heights water treatment plant. The two pipelines that were not damaged continue to transfer water to the Durban Heights plant.

Due to the temporary decommissioning of the two damaged pipelines, Umgeni Water has had to use three shaft pumps to transfer water from Inanda Dam to the plant to augment raw water supply. Additional water is also being sent through the two functioning Nagle Dam-Durban Heights plant pipelines.

There is currently a deficit in raw water supply to the plant and consequently reduced production and supply of potable water (drinking water). The shortfall amounts to, on average, between 40 million and 50 million litres per day. The shortfall will remain until the two pipelines are repaired and recommissioned. 

Repair of the two pipelines is expected to be a 10-12 month project. One of the pipelines is steel and the other concrete. They are high pressure and transport large volumes of raw water.

Status of Potable Water Production as at June 3:

The Northern Region: The Hazelmere water treatment plant, outside Verulam, was producing 60 million litres (60 Ml/d) of potable water (drinking water) on Friday. This is 15 million litres less than its average daily production of 75 million litres and is due to repairs that are being conducted on the Aquatan roof liner of the floating deck of reservoir 2 at the plant, which was damaged during the rains in April this year.

The reduced production was necessitated by partial shutdown of the plant for the work to be undertaken. The work was scheduled to be completed last Friday, after which production will be ramped up to reach 75 million litres.

The municipalities of eThekwini Metro and iLembe District Municipality and a private sector entity, Siza Water, are supplied from the Hazelmere plant. In the meantime, while work progresses, customers have continued to effectively manage and supply to consumers the reduced amounts of water being supplied to them. Umgeni Water wishes to thank the customers for their co-operation and assistance in this regard.

Durban Central, Durban South, Durban North and Durban Inner west: Two water treatment plants serve eThekwini Metro for reticulation to these areas. They are Durban Heights and Wiggins.

Durban Heights: As at June 3, on average between 490 million litres and 500 million litres per day of potable water were produced and supplied to eThekwini Metro. The municipality, in turn, supplies the north, south, central and inner west of Durban. There is currently a daily shortfall of between 40 million and 50 million litres against the amount of potable water that Umgeni Water is contracted to supply eThekwini Metro.

This is due to the temporary decommissioning of two pipelines — 1 and 2 — that, together with pipelines 3 and 4, convey raw water from Nagle Dam to Durban Heights for treatment. Pipelines 1 and 2 were extensively damaged in the April floods. To augment supply, three shaft pumps are being used to transfer raw water from Inanda Dam and additional water is being transferred through pipelines 3 and 4.

A shortfall in raw supply and accompanying shortfall in potable water supply remains. The plant will begin receiving its full volumes of raw water after the two pipelines are repaired and recommissioned. Restoration of the two pipelines is estimated to be a 10-month project.

Wiggins: On June 3, potable water production amounted to, on average, 327 million litres. Production has been steadily increasing since the weekend of May 28 and 29, after raw water turbidity-related problems were encountered from Thursday May 26, due to heavy rains the previous week and poor water quality in catchments. A decision was taken at that time to reduce inflows and production to avert the possibility of producing potable water that was non-compliant with SA National Standards (SANS) 241 for drinking water quality

Of the 327 million litres produced on June 3, about 325 million litres were supplied to eThekwini Metro. Umgeni Water is contracted to supply 301 million litres per day.

The average daily production for the entire May was 305 million litres, of which an average of 298 million litres were supplied to eThekwini Metro daily. Therefore, a deficit in supply against contracted volumes occurred in May amounting to an average of three million litres per day.

Very high turbidity (muddy) water is being received from Inanda Dam and the Wiggins plant treatment processes are unable to treat this water at 100% production rates. Hence the reduction in the amount of water being produced while this problem still exists. Umgeni Water has introduced a new chemical to try to treat this water at full production capacity of the plant.

The objective is to reach 100% production in the shortest possible period and when nephelometric turbidity unit (NTU) reaches 100. NTU is used to measure levels of turbidity in water, and on May 26 it peaked at a high of 400. It has since begun reducing and by June 3, the NTU level reached 150, which is manageable for treatment purposes. Once full production is reached and maintained, the deficit against contracted volumes will be eradicated.

The Wiggins system also supplies the Amanzimtoti Water Works through the South Coast Augmentation for eThekwini Metro to distribute to Amanzimtoti and further south within its boundaries.  

Shami Harichunder is Umgeni Water's corporate stakeholder manager.