Dam wall collapses in Benoni
A slap of retainer wall of Middle Lake in Benoni collapsed on 23 December 2018. An operation to restore the slab that collapsed on the retainer wall of the lake in Benoni CBD on the corner of Bunyan Street and the N12 resulted in the closure of both the roads. According to Ekurhuleni Disaster Emergency Management Services (DEMS) spokesperson, William Ntladi, the roads will be closed until the slab can be repaired. This resulted in the roads being closed until the weekend in order to ensure the safety of community members and to effectively find a solution to repairing the collapsed slab. “At present we are reducing the water levels in the dam, as per instructions of the engineers in order to reduce the water pressure. The water is being channelled via the water-relaying system from emergency services. “The water-relaying system is very powerful and has high volumes of water flowing through.
“This could lead to an overflow which could obstruct the operation. The water is flowing into the other dam (the lake on Tom Jones Street) and we are monitoring the situation. Should there be an overflow we need to act quickly and this is the reason for closing off the roads.
“The engineering company has come up with a plan for us for when they will start and how they will operate. They will have to evaluate all the slabs and the inside of the dam wall as well before any repairs can commence. We are in the rainy season so the sooner this is resolved the better. By then we will need the contractor to be able to have sealed the collapsed slab.”
Ntladi added that the various departments involved with the operation are on standby at the site 24/7. “This is a multi-departmental operation that includes DEMS, Ekurhuleni Metro Police Department (EMPD) and the Ekurhuleni water department as well as the engineers so there are many stakeholders involved. “Every day we have a meeting to discuss our findings and reports of the previous day as we need to find a solution to the problem at hand very soon.”
Prevention is better than cure. A well-coordinated join operation between all spheres of government, which includes local, provincial and national government has helped to avoid a catastrophic disaster that would have cost lives and serious damaged to the infrastructure following the caving in of part of the spillway at Middle Lake Dam in Benoni.
The Executive Mayor of City of Ekurhuleni, Councillor Mzwandile Masina, moved swiftly to establish an inclusive joint operation after the city was alerted of an imminent danger of the Middle Lake Dam. A call was received by Ekurhuleni Disaster and Emergency Management Services on 23 December about the caving in of the spillway at Middle Lake Dam. In response a Joint Operations Committee (JOC) was immediately established on 23 December, which helped to prevent loss of lives and damage to properties downstream. The JOC is made up of experts from key departments in the City of Ekurhuleni, Gauteng Department of Agriculture and Rural Development, provincial and national Department of Water and Sanitation and Rand Water.
Since the incident was reported, the JOC managed to divert the water at the onset, then moved on to deploy seven suction pumps into operation to reduce the dam level. The lowering of the dam level will help to avoid the complete collapse of the spillway thus leading to massive flooding. Secondly the lowering of the dam level will assist in allowing engineers access to the damaged slab for repairs. In order to beef up operations, the JOC will enlist the use of six siphon suction pumps to further lower the dam level. This operation is planned to kick start as soon as the siphon pumps are in place. Following the lowering of the dam, then work will start to remove the damaged concrete slab and compacting of the voids underneath the spillway. Whilst this is a temporary measure, it is expected that it will take a number of months to complete the refurbishment of the spillway.
The roads around the Middle Lake Dam, including on and off-ramps to N12 via Tom Jones Road and Bunyan Street remained closed whilst the operation was underway.
During his inspection visit, Executive Mayor has pleaded for patience from all parties. “This is a necessary operation to avert a major disaster. We are calling on people of Ekurhuleni to exercise caution and be patient. Once the siphon suction pumps are in place, road usage will resume”. The Executive Mayor also asked members of the public to steer clear of the operational area, as this can pose danger to them and impede officials on site and disrupt operations.
Source: Kempton Express and City of Ekurhuleni