Johannesburg – Two more floodgates have been opened at Vaal Dam, and high water levels are anticipated in Douglas town, Northern Cape.
The Department of Water and Sanitation said the floodgates were opened at Vaal Dam on Saturday, (18 February 2023), as part of “continuous dam safety precautions”.
The department said the two floodgates add to the 10 that were already opened at the dam.
“At Bloemhof Dam an outflow was increased to 2400 cubic metres per second by this afternoon,” the department said.
“High water levels and possible flooding is anticipated at Douglas Town in the Northern Cape, at the confluence of Vaal and Orange rivers due to releases from Vanderkloof and Bloemhof dams, and residents are urged to be alert and may need to evacuate where necessary to avoid harm or loss of lives.”
The department urged communities along the Vaal and Orange river system to remain vigilant and put measures in place to prevent casualties, minimise disruptions when water levels rise.
With the continuing heavy rains in large parts of the country, many rivers are overflowing, and most dams are full and spilling.
The Vaal and Orange River System is also experiencing rapidly rising water levels and has necessitated the opening of the gates to safeguard the infrastructure from collapsing.
Since rainfall and floods are natural phenomena and therefore control of such events may be limited.
The department said it “advises against putting essential services and human settlements within parts of the floodplains, where there is the likelihood of frequent flooding, that is within a 1 in 100-year flood line”.
Every year ahead of the high-flow summer season rains, the department said it develops a Flood Preparedness Plan and implements flood monitoring and forecasting systems, assessing the likelihood of flood incidents.
The department said it also checks on its preparedness to mitigate the adverse effects of these floods on its infrastructure and guarantees the full capacity of its storage reservoirs.
“All requisite measures are put in place to ensure that the department will be able to manage floods effectively,” said the statement issued by the department
“All gauging equipment at sites used for flood monitoring is equipped with real-time river and dam level data transmission capability.”
The department said data was analysed to determine rainfall, river, and dam level trends which enable the detection of the possibility and timing of flooding.
Some of the dams owned and operated by the department have built-in additional capacity for limited flood retention and some have gated spillways.
“These reservoir components make it possible to lessen flood impacts by reducing them,” explained the department.
“The gates make it possible to pre-emptively release water from reservoirs rapidly and thereby opening more space to store proportions or the entire volume of potentially destructive flood peaks.”
