Vaal River System Update: Bloemhof Dam outflows increased to manage rising water levels, five sluice gates at Vaal Dam remain open
The Department of Water and Sanitation (DWS) increased water releases at Bloemhof Dam at 11h00 this morning to 2200 cubic metres per second (mᵌ/s); and further increased water releases at 14h00 to 2450 mᵌ/s; at 16h00 to 2700 mᵌ/s, and the last increase will be at 18h00 to 3000 mᵌ/s in order to manage the rising dam levels which are at 116.5%. These adjustments are necessary to manage the sustained high inflows and ensure safe operation of the dam. The water outflow at the dam was last increased to 2000 cubic metres per second mᵌ/s yesterday evening.
To manage the rising levels of water at the Bloemhof Dam, five radial gates have been opened. Three of the gates are fully opened and two are partially opened at different metres. The Bloemhof dam has 20 radial gates that are operated differently from that of the Vaal Dam but are used to effectively manage water levels at Bloemhof Dam.
Vaal Dam continues to rise with water levels at 112.85% and 1 248.11 mᵌ/s inflows from the upper catchment. The five sluice gates remain open with a discharge remains of 793 mᵌ/s to manage the water levels at the dam.
The current controlled water releases at both the dams may lead to possible overtopping of riverbanks downstream, and this will affect infrastructure built in lower-lying areas within the 1 in 100-year floodline.
People living within the floodline of the Vaal River downstream of the Vaal Dam and the Bloemhof Dam should evacuate and move to a safe area, and remove valuable equipment, movable infrastructure and livestock.
One sluice gate remains opened at 2.5 metres to enable water releases at Grootdraai Dam located in Mpumalanga in the Upper Vaal River Catchment, upstream of the Vaal Dam. The Dam was recorded this morning to be at 101% full supply capacity.
The Integrated Vaal River System (IVRS) is experiencing very high inflows which dictates that dams within the system have to be on high alert and implement the dam safety protocols based on the levels of water.
The DWS continues to monitor inflow water levels in the IVRS 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.
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 Department is therefore implementing these necessary controlled water releases at the dams as part of dam safety precautions to safeguard the infrastructure and protect human life.
For more information, contact
Wisane Mavasa, Spokesperson for the Department of Water and Sanitation
Cell: 060 561 8935
E-mail: mavasaw@dws.gov.za.
#GovZAUpdates
