Vaal Dam stays above 100% as managers lift outflows to ease levels

The Vaal Dam remained above full supply level for a third straight day between 8 and 10 June 2026, with managers gradually increasing releases on 10 June as inflows continued to exceed outflows earlier in the reporting period.

Storage and daily readings

The reservoir was recorded at 105.23% on 8 June, then fell to 104.96% on 9 June and to 104.84% on 10 June, according to data from The Reservoir, the Water Resource Information Centre for the Catchment Management Forums of the Upper Vaal Water Management Area.

Inflows, outflows and gates

Across the three-day window inflows held in the tens of cubic metres per second while outflows were initially minimal. The Reservoir reported:

“Inflow: 64.0m³/s” and “Outflow: 3.8m³/s” for 8 June.

“Inflow: 66.8m³/s” and “Outflow: 3.8m³/s” for 9 June.

On 10 June the operational response changed:

“Inflow: 58.4m³/s” and “Outflow: 20.4m³/s”.

The data show that no flood gates were opened on any of the three days, with The Reservoir listing “Gates Open: 0” for 8, 9 and 10 June.

Downstream: Vaal Barrage response

Downstream readings at the Vaal Barrage rose in step with the higher releases from the dam. The Reservoir recorded the barrage level at 7.4 metres on 8 June, 7.5 metres on 9 June and 7.6 metres on 10 June.

Barrage outflow increased from 5.0m³/s on 8 June to 5.1m³/s on 9 June, rising to 15.2m³/s by 10 June as the higher upstream releases reached the barrage.

Water temperature trend

The Reservoir data show a warming trend at the barrage over the three days: 12.4°C on 8 June, 12.9°C on 9 June and 14.5°C on 10 June.

What the figures show

The readings indicate that while the Vaal Dam’s percentage storage eased slightly each day, it remained comfortably above full supply level throughout the period. The recorded increase in outflow on 10 June appears to be a controlled step to reduce storage without opening flood gates.