Sluice-Gates Opened at Dams


By Surihe Gaomas WINDHOEK Recent intermittent rains prompted NamWater, the water utility company, to open the sluice-gates at Naute and Hardap dams primarily to prevent flooding in the south. NamWater’s Corporate Communications Manager John Shigwedha said the sluice-gates were opened as a precautionary measure to prevent overflowing and flooding, and also to stop dam walls being damaged by excess water. Naute Dam normally operates at 100 percent full capacity, but it has exceeded its capacity by 102.4 percent while still receiving inflows at a rate of 20 cubic meters per second. The current inflow is expected to take the dam to 103 percent, while the opening of the sluice-gates would reduce its water to 95 percent of capacity. A huge volume of 5.8 million cubic meters of water was released from the dam over a five to six hour period. As a precautionary measure, residents and tourists alike in the vicinity of thedams were cautioned in advance about the opening of the sluice-gates. Naute Dam is located some 45 kilometres west of Keetmanshoop and is fed by the Lowen River. It normally supplies water to the southern town for both irrigation and domestic purposes. The sluice-gates of the Hardap Dam were opened for the first time since January 1963. The dam operates at 90 percent capacity and now stands at 85,8 percent full with water still flowing in at a rate of 34 cubic meters per second. “Since it is still relatively early in the rainy season and the potential of further inflows into Hardap and the resultant floods is very high, it is necessary to release the water from the dam this early in order to prevent or minimise flooding,” stated Shigwedha. At a release rate of 400 cubic meters per second, it will take twelve hours to get the Hardap Dam down from 86 percent to 80 percent. During this period 14 to 25 cubic meters of water will be released from the dam. Over the weekend, water was released slowly at Hardap and then increased to determine the flow capacity of the river. Hardap Dam is situated 20 kilometers north of Mariental and about 250 kilometers south of Windhoek. It is normally fed by the Fish River and supplies water to the town for domestic and irrigation purposes. In an effort to minimise flood damage downstream, the sluice-gates of Avis Dam were also opened last week for the second time this month. Avis Dam acts as a retention pond in the event of a flood in the Klein Windhoek River. The almost full dam dropped its water level to 2 meters.