The Department of Water and Sanitation (DWS) says the fourth dam - upstream of Riverlands in the Swartlands Local Municipality - has been cleared through a side channel spillway created to prevent a more catastrophic collapse of the dam wall.
The department said during an inspection on 12 August 2024, it was established that there is a progressing piping failure (on the downstream slope) at the highest section of the dam wall.
“The integrity of the dam was compromised and hence the possibility of failure was detected.
"Subsequently, the decision was taken to empty the dam to protect the lives of the community members living downstream.
“The 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 day light, to enabled it to be managed more easily,” the department said in a statement.
The department said, should Dam 4 failed late in the evening or early morning hours while the public downstream was asleep, the consequences could have been far worse.
The department noted that the fourth dam emptied faster than anticipated, however, the public was precautionarily evacuated, hence no injuries and loss of life were reported.
“The members of the public, who were evacuated, have returned to their homes and the dam wall of Dam 4 has not failed. Very little additional damage was caused by the release of water from Dam 4.
“The damage to infrastructure was caused by the floods of the dam breaks of the previous three dams during the early hours of last week,” the department said.
The department reiterated its commitment to safeguard the lives of the public during emergency conditions, although this sometimes results in difficult decisions having to be taken, including the precautionary evacuation of people if deemed necessary,” the department said.
Investigation into dams failure extended
Meanwhile, Water and Sanitation Minister, Pemmy Majodina, has granted the departmental engineers an extra week to conduct diligent and adequate investigation into the reason behind the failure of three farm dams located in Riverlands.
This follows the failure of three farm dams located in Riverlands that breached, resulting in flooding that caused severe property and infrastructure damage to the affected area, leading to hundreds of people being provided with humanitarian assistance.
Majodina visited the area on 11 August 2024 to get a first-hand information of the disastrous occurrence and was briefed by the team of engineers dispatched by the department to normalise the situation in the area.
The Minister then instituted an investigation on the breach of the three dams and whether the owners of the dams have proper authorisation from the department.
A report was expected in seven days from the day of Majodina’s visit.
Whilst the team on the ground has been working around the clock to expedite the compilation of the report requested by the Minister, the department emphasised that it has 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 the 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,” the department said.
The Department of Water and Sanitation is committed in conducting its regulatory function diligently and depending on the outcomes of the investigation, those responsible for the failure of the three dams will be held accountable. – SAnews.gov.za
