The Vaal Dam’s storage level edged downward during the week of 24 to 30 August 2026, moving from a peak of 101.00% at the start of the week to 100.75% by Friday, according to the weekly hydrological report compiled on behalf of Rand Water and the Department of Water and Sanitation.
Storage stood at 101.00% on Monday, 24 August, and held at the same level on Tuesday, 25 August.
It then fell to 100.88% on Wednesday, 26 August, remained unchanged on Thursday, 27 August, and eased further to 100.75% on Friday, 28 August.
The report noted that “not all abstraction and evaporation losses from Vaal Dam are reflected in the above data,” which may account for part of the gradual decline.
Around the same period last year, the Vaal Dam stood at a higher level, recording 107.1%.
Inflow into the dam started at 44.1m³/s on Monday before dropping to 39.3m³/s on Tuesday, the week’s lowest reading.
It then rose sharply to 45.3m³/s on Wednesday, the week’s high point, before easing to 43.5m³/s on Thursday and 41.5m³/ss on Friday.
Dam discharge, by contrast, stayed constant at 16.8m³/s every day, and no sluice gates were opened at any point during the week.
At the Vaal Barrage, the water level held at 7.6m on Monday and Tuesday before dipping to 7.5m from Wednesday through to Friday.
Barrage discharge followed a similar pattern, easing from 22.7m³/s on Monday and Tuesday to 22.6m³/s for the remainder of the week.
Water temperature at the barrage started at 12.6°C on Monday, dropped slightly to 12.2°C on Tuesday, then rose back to 12.6°C on Wednesday.
It climbed further to 14.5°C on Thursday, the week’s highest reading, before easing to 14.1°C on Friday.
Data for Saturday and Sunday had not yet been recorded at the time of publication.
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