Sluice gates opened at Grootdraai Dam
Grootdraai Dam in Lekwa requires sluice gates to be opened to protect the dam infrastructure from failing.
Floodgates were opened to safeguard dams as water levels were high due to the heavy rain.
According to a statement from the Department of Water and Sanitation, dated February 21, the rain in most parts of the country led them to implement dam safety protocols to prevent dam failures and major disasters in the country.
As part of the protocols, they open sluice gates when dams breach the full capacity mark and overflow. This is to prevent the infrastructure from failing, which may lead to a dam bursting.
The department has to manage floods by operating sluice gates, controlling what is coming into dams and balancing inflow and outflow.
They also follow flood contingency procedures and take into consideration the pressure that the dams can handle to avoid the failure of dam walls.
The Integrated Vaal River System experienced high inflows, which dictated that dams in the system had to be placed on high alert.
Grootdraai Dam in Lekwa was a dam that required sluice gates to be opened to protect the dam infrastructure from failing.
They opened two sluice gates at two metres each when the dam level stood at 102%, but due to the huge inflows that raised the levels to 113%, three gates were opened at three metres each to bring the situation under control.
Grootdraai Dam was at 101.89% with an inflow of 242m3/s and an outflow of 692m3/s on February 20 at 07:00.
The three gates were still open at three metres each, but the department will begin reducing one gate by one metre until the gate was fully closed and keep monitoring the level.
The water released from the dam combines with flows from the Katbos and Leeuspruit into the Vaal River downstream.
There is also water coming from the stream that passes through Standerton. This water does not flow into the Vaal River but goes back towards low-lying areas of the town during heavy rain.
The department urged the public to avoid building along flood lines and move to higher ground when water levels in dams, rivers and streams increase.
They encouraged municipalities to maintain stormwater drainage systems to prevent blockages that may lead to flooding of streets and properties.
