Department of Water and Sanitation continues to monitor water levels in the Vaal River System to ensure full storage capacity and safety of infrastructure
The Department of Water and Sanitation continues to monitor inflow water levels at the Vaal Dam to ensure that necessary precautions are in place in line dam safety standards and hydrological monitoring systems to safeguard infrastructure and attenuate flood conditions within the constraints of existing high dam levels.
The Department, together with its utility, Rand Water follow operating rules and procedures when releasing water from the Vaal Dam and the Barrage during this National State of Disaster necessitated by the ongoing floods due to heavy rains.
The Vaal dam is currently at 120% capacity, therefore 12 flood gates remain open and outflow at Bloemhof Dam was kept at 3200 cubic metres per second. According to hydrological monitoring and forecasting systems, the Vaal Dam is receiving about 3000 cubic metres per second and releasing 2300 cubic metres per second through the opened gates. At the Barrage, water levels remain at 99% throughout the releases.
The Department gradually implemented the releasing protocols since on 11 February 2023 when the first gate was opened, and 3 additional gates were opened on intervals on 12 February and the 5th gate on Monday 13th. The patten continued throughout the week and by Friday 17 February, 10 gates were opened and two more on Saturday, as inflow increased upstream the dam due to the heavy rainfalls.
The Department also notes that along the Vaal River, the Vaal Barrage was also experiencing rising water levels that may have been caused by the inflows from Suikerboschrand, Klip and Rietspruit tributaries over the high flow period due to the heavy rains in the catchments of these rivers.
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Through various platforms, the department engages, share hydrology reports and updates on weekly basis on the water levels in the dam, and on daily and hourly basis when there are rainfall and/ or possibility of floods due to rising water levels upstream the dam, with recommendations in order to send early warning systems and activate evacuation plans in case of flooding.
Stakeholders included are the Disaster Management operations in Emfuleni and Metsimaholo local municipalities, local police services (police water wing), farmers and locals upstream and downstream along the Vaal River System.
The heavy rains in most parts of the country have led the Department to implement dam safety protocols to prevent dam failures and major disasters in the country.
As part of the dam safety protocols, sluice gates are opened when dams breach the full capacity mark and overflow to prevent the infrastructure from failing which may lead to a dam bursting and causing a disaster of unimaginable magnitude.
The Integrated Vaal River System (IVRS) experienced very high inflows which dictated that dams in the system have to be on high alert and implement the dam safety protocols based on the levels of water.
Since rainfall and floods are natural phenomena and control of the events may be limited, the Department continues to advice against putting essential services and human settlements within parts of the floodplains where there is likelihood of frequent flooding, that is within a 1 in 100-year floodline.
