The Vaal Dam has remained above 100% capacity for nearly two weeks, with water resource managers carefully balancing inflows and outflows to manage downstream conditions across the Upper Vaal Water Management Area.
Vaal Dam stays full as inflows ease and gate operations shift
The Vaal Dam recorded a level of 101.38% on Wednesday, maintaining its position above full supply capacity for a 13th consecutive day, according to the latest data from The Reservoir, the water resources information centre for the catchment management forums of the upper Vaal water management area.
Inflows into the dam on the day stood at 140.7m³/s, while outflows were recorded at 111.6 m³/s, with one gate open.
The Reservoir noted that on Tuesday, the dam was sitting at 101.38%, though conditions had been markedly different.
Inflows were significantly higher at 247.7 m³/s, while outflows were sharply reduced to just 11.0 m³/s, with no gates open at that point.
“For Vaal Dam, the recommendation today is to close all valves and open one gate,” The Reservoir reported on Tuesday.
On Monday, inflows were recorded at 167.1 m³/s with outflows also at 11.0 m³/s and no gates open, as the dam sat at exactly 101.00%, marking its 11th consecutive day above capacity.
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Downstream management tightens
Conditions at the Vaal Barrage have also been closely monitored, with levels rising from 7.4 metres on both 9 and 10 March to 7.6 metres by 11 March.
Outflows at the Barrage climbed substantially over the same period, from 44.3 m³/s on 9 March to 22.5 m³/s on 10 March, before surging to 179.8 m³/s by 11 March.
Water temperature at the Barrage was recorded at 20.2°C on 11 March, easing slightly from 21.0°C the previous day.
The sharp increase in Barrage outflows by 11 March aligns with the opening of a gate at the Vaal Dam.
The Reservoir has been tracking these cascading effects across the system as managers work to balance storage levels with flood risk.
“For Bloemhof Dam, the recommendation today is to increase the discharge to 150m³/s at 10:00,” The Reservoir stated in its 10 March operational guidance.
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