THE water level in the Oanob dam to the west of Rehoboth has reached the point of overflowing overnight after heavy rains in the catchment areas of rivers feeding into it.
Residents of Rehoboth could hardly contain their excitement as they flocked to the dam to see firsthand how millions of litres of water spill over the secondary wall of the dam.
According to NamWater’s Dam Bulletin, the water level in the dam rose from 78% on Monday to more than 105.6% since Monday.
Most of the inflow occurred on Tuesday and Wednesday.
The abundance of water in the dam allowed NamWater officials to also open the sludge gates at the bottom of the main dam wall that used to be the highest dam wall in Namibia.
Until the wall of the Neckertal Dam was completed in 2018, the wall of the Oanob Dam at 52.5 metres was the highest in Namibia. The height of the Neckertal Dam’s wall is 60 metres.
Like the Neckertal Dam and the Swakoppoort Dam, the Oanob Dam has a spillway system to release excess water from the dam. The volume of water that goes down the spillway is not measured but an idea of how much water is flowing out of the dam can be determined by checking the inflow that was measured at more than 75 cubic metres per second on Wednesday evening.
The sludge gates were releasing 16 cubic metres of water per second. The main function of the sludge gates is not to control the water level in the dam. The gates are used to get rid of debris and mud that has gathered at the bottom of the main dam wall.
Water from the dam started to flow over the spillway at about 23:00 on Wednesday night.
Water from the Oanob Dam flows down into the Kalahari Desert where it disappears under the dunes at Tsumis.