Vaal Dam drops below full capacity after 20 days: Here’s this week’s level

2026-03-19 - 10:30

The Vaal Dam has dipped just below its full supply level after more than three weeks above 100%, while interconnected dams across the Upper Vaal Water Management Area continue to hold record-high volumes, offering rare reassurance about South Africa’s water security heading into the dry season. Vaal Dam eases from its peak but stays well-supplied After an extraordinary run of 20 consecutive days above full capacity, the Vaal Dam recorded a level of 99.62% on 19 March 2026, according to the latest data from The Reservoir, a water resource information centre for the Catchment Management Forums of the Upper Vaal Water Management Area. The reading marks the first time since late February that the dam has dipped below the 100% threshold, though it remains at near-full levels. The descent from the peak has been gradual. The Reservoir recorded the dam at 100.50% on 16 March, with an inflow of 60.4 cubic metres per second and outflows held steady at 113.8m3/s, with one gate open. By 17 March, the level had eased to 100.25%, and on 18 March it reached exactly 100.00%, the twentieth consecutive day above full supply level, before slipping to 99.62% the following morning. “Over 100% – 20 consecutive days,” The Reservoir noted in its 18 March update, capturing the scale of the sustained overflow period. A day earlier, it recorded: “Over 100% – 19 consecutive days.” Throughout this period, outflows remained constant at 113.8m3/s with a single gate open, while inflows fluctuated between 42.0m3/s on 18 March and 60.4m3/s on 16 March. ALSO READ: Cape Town water usage surges as dams plunge to 50% The Vaal Barrage absorbs the downstream flow Downstream, the Vaal Barrage has been receiving the outflows and holding steady. On 19 March, The Reservoir reported a barrage level of 7.5 metres, with an outflow of 133.5m3/s and a water temperature of 20.9°C. The figures reflect a slight easing from the previous two days, when the barrage outflow reached 143.6m3/s on 18 March and 144.2m3/s on 17 March. “Level: 7.5m. Outflow: 133.5m3/s. Water Temp: 20.9°C,” The Reservoir reported for the barrage on 19 March, with the level holding at 7.6 metres only on 16 March before settling back down. The barrage’s outflow has consistently exceeded that of the dam itself, a pattern that reflects its role as a flow-regulation point further along the Vaal River system, managing water before it continues downstream toward Bloemhof Dam and, eventually, the Orange River. The integrated system tells a story of abundance The broader Integrated Vaal River System, with readings updated on 17 March 2026, paints a picture of a water network operating at near-maximum capacity across every major storage point. Woodstock Dam stood at 99.7%, with water being transferred via pumped transfer to Sterkfontein Dam, which itself recorded an exceptional 99.9%. “Water flows down Nuwejaarspruit into the Wilge Rivier that in turn flows into the Vaal Dam,” The Reservoir explained of Sterkfontein’s contribution to the system. Grootdraai Dam, feeding directly into the Vaal River toward the Vaal Dam, was recorded at 99.6%. “Water flows out into the Vaal River that flows to Bloemhof Dam,” The Reservoir noted of the Vaal Dam’s own downstream contribution, with that dam registering 98.2%, the lowest in the network, but still comfortably near-full. Lesotho’s dams add a cross-border buffer The Lesotho Highlands Water Project continues to play a critical supporting role. Mohale Dam in Lesotho recorded a remarkable 102.5% above its full supply level, with water transferred via gravity to Katse Dam. Katse, in turn, sat at 98.9%, with water being pumped into the Liebenbergsvlei River. “Water is being transferred via gravity-fed transfer to Katse Dam,” The Reservoir reported of Mohale, while of Katse it noted: “Water is being pumped into the Liebenbergsvlei that flows into the Wilge Rivier that in turn flows into the Vaal Dam.” The cross-border flow means that even as the Vaal Dam edges back from its overflow high, the pipeline of water feeding into it from the Lesotho highlands remains effectively full, providing a substantial upstream buffer as the summer rainfall season begins to wind down. What the numbers mean for water users With nearly every dam in the Upper Vaal system sitting above 98%, the region enters the traditionally drier autumn and winter months from a position of significant strength. The Reservoir’s data showed that as recently as 16 March, inflows of 60.4m3/s were still arriving at the Vaal Dam even as controlled releases of 113.8m3/s were being maintained, a sign that meaningful rainfall events continued well into mid-March. “Inflow: 58.3. Outflow: 113.8m3/s. Gates Open: 1,” the centre reported for 19 March, confirming that management of the reservoir remains measured and deliberate rather than reactive. Bloemhof Dam’s level of 98.2% confirms that the abundance is flowing through the system, with water ultimately making its way down the Vaal River, through the Douglas Weir, and into the Orange River, completing a hydrological chain that stretches from the Lesotho highlands to the Northern Cape. READ NEXT: Knysna mayor assures residents Day Zero won’t happen despite dam at 22%