Coen Welsh | Nov 14, 2017 | 0
Hardap Dam level stabilizes
Massive inflow into the Hardap Dam near Mariental occurred earlier this week after a spate of good rainfall was experienced in its catchment area. This prompted the opening of the sluices on Tuesday to lower the level of the dam. Over a three-day period some 100.7 million cubic metres of water was released from Hardap to prevent later flooding of Mariental which lies downstream from the damwall. A massive inflow on 24 March saw the dam take as much as 36.412 million cubic metres over a 24-hour period taking the percentage of full capacity from 44.5% (Last reading) to 56.8%. Again significant inflows were recorded on Tuesday around 11pm with an inflow of 18.297 million cubic metres over a 3-hour period and later at mid-day, during just one hour, another 6.031 mcm was recorded as entering the dam raising the level to 65.1 %. The sluices of the Hardap Dam were opened on Tuesday at 14:00hrs with the content then at 69,5%. But the water level kept rising and after being opened for more than a 15 hours the percentage of full capacity stabilised at 74.7%. This indicated that the inflow equalled the outflow.
Andre Mostert, the Hydrology Manager at NamWater told the Economist that the sluice gates were closed on Wednesday at 14:30 after the dam level had subsided to the 70% benchmark. During the time the sluices were open, 100.7 mcm of water were released at the rate of 600 cu.m/sec. He also stated that for the time being, the dam level is stable and floods are not likely to occur. “Only if we receive more rainfall and more inflow occurs, that is when we will be prompted to open the sluice gates again.”he added. The sluices of the dam were last opened on 29 March 2012 to avoid flooding. Meanwhile the Omatako Dam near Hochveld had slight inflows, its content improving from 18% of full capacity on Monday to 21.1% on Wednesday. The collector reservoir, Von Bach Dam only saw a 0.6% increase over the two-days, rising to 51.6%.
Swakoppoort Dam which transfers water to Von Bach also had a slight inflow in the two-day period as it moved from 59.8% to 61.1%, indicating some precipitation in the catchment area.