Dam collapse mired in power struggle, confusion

A dam burst on Saturday led to local officials evacuating residents, with the gushing water damaging some homes. Picture: Henk Kruger/Independent Newspapers

A dam burst on Saturday led to local officials evacuating residents, with the gushing water damaging some homes. Picture: Henk Kruger/Independent Newspapers

Published Aug 19, 2024

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A power struggle appears to be at the centre of conflicting evacuation orders for Riverlands residents in the Swartland Municipality following what local officials described as another flash flood at the weekend.

However, the national Department of Water and Sanitation (DWS) was quick to calm fears, saying the situation was “normal” and there was no need for evacuations while the frustrated local municipality, which blamed the department for the latest flash flood, confirmed that more than 100 people have been affected.

The DA-run municipality north of Cape Town consists of towns such Malmesbury, Darling, Piketberg and Moorreesburg, among others.

A dam burst on Saturday led to local officials evacuating residents, with the gushing water damaging some homes.

No injuries or fatalities were reported, however, several residents were treated for shock at the Riverland clinic, according to the municipality.

The incident happened amid Water and Sanitation Minister Pemmy Majodina granting departmental engineers an extra week to conduct an investigation into what led to the failure of three farm dams that breached resulting in flooding.

Acting national spokesperson for the department, Andile Tshona, on Friday said the probe will see if the owners had proper authorisation from the department and a report was to be compiled.

“While the team on the ground has been working around the clock to expedite the compilation of the report requested by the minister, it has had to balance the investigation work with its intervention to mitigate the risk of the failure of the fourth dam which was at a risk of severe damage as well.

“The department mobilised a construction team currently working at Clanwilliam Dam project for additional capacity to lower the risk of failure of the fourth dam.

“Furthermore, the department assessed the likelihood of failure of other dams in the area due to persistent rains and a saturated catchment which could have led to other dams reaching their maximum storage capacity,” said Tshona.

He confirmed on Sunday that the department was aware of the latest incident and “wishes to assure the residents of Riverlands in Swartlands Local Municipality that the situation was normal in the area and there is no need for evacuation”.

On the cause of the latest flooding, Tshona said water started flowing quicker than expected through the spillway that was created to minimise the risk of failure of the fourth dam that was on the verge of giving in.

“The department mobilised its personnel located in the Clanwilliam Dam project to open up the spillway on the fourth dam further and allow the water level in the dam to drop by at least one metre per day.

“Water started flowing quicker than expected, as a result there was understandable concern from community members. The department would like to assure community members that the fourth dam is almost empty and water levels in the river should begin to subside.

“Should there be any further heavy rainfall, the dam would not store water to threaten the stability of the partially failed wall,” he said.

The municipality said the situation on the ground stabilised on Monday and some residents were able to return to their homes.

No additional damage to infrastructure was reported. “The Swartland Municipality made the call to evacuate Riverlands residents living north of the Riverlands Primary School.

“Swartland Municipality is currently caring for 128 residents spread across two community centres. Residents are receiving food, shelter, clothing and other aid.

“The municipality’s Community Development Department has also been working with Sassa and the Department of Home Affairs to assist residents who have lost all essential paperwork.

“Aid and assistance are also given to residents who have returned to their homes and have suffered severe losses,” it said.

The municipality said the flash flood undid the work already done in repairing water infrastructure.

“The first pipes that were reinstalled were washed away and the municipality will have to start the repairs all over again.

“While the water network is down, the municipality continues to provide water to residents by means of a fleet of tankers operating in the area.

“Although the initial plan indicated to the municipality was to slowly release water from this dam to minimise the risk of possible flooding, the plan by the department failed.

“The municipality is very disappointed since it requested on several occasions not to further intervene with the dam, because the situation had stabilised, and the risks were mitigated satisfactorily.

“The municipality’s proposal was to leave the fourth dam and do any necessary work in the summer, when drier conditions will have worked in our favour.

“The department specialists on site however decided to further lower the dam levels via a newly dug spillway and unnecessarily triggered the unexpectedly fast release of water resulting in the coming down of the river once again, following the path it carved last week,” it said.

In a statement last night, the department said the reason it emptied Dam 4 upstream of Riverlands residents by means of a side channel spillway was to prevent a more catastrophic collapse of the dam wall.

“The department established that there is a progressing piping failure (on the downstream slope) at the highest section of the dam wall during an inspection on August 12, 2024. The integrity of the dam was compromised and hence the possibility of failure was detected.

“Subsequently, the decision was taken to empty taken to empty the dam to protect the lives of the community members living downstream.”

It said the process of emptying of the dam through the spillway was planned to drain the dam during daytime (from 10am to 4pm) to ensure that the increased outflow from the dam would occur during daylight, to enable it to be managed more easily.

“Should Dam 4 have failed late in the evening or early morning hours while the public downstream was asleep, the consequences could have been far worse.

“Dam 4 emptied faster than anticipated, however, the public was precautionarily evacuated and hence no injuries and loss of life were reported.

“The members of the public who were evacuated have returned to their homes. The wall of Dam 4 has not failed. Very little additional damage was caused by the release of water from Dam 4.”

Cape Times