Flood alert for Okavango and Orange rivers

PEOPLE living and working along the Orange River on the southern Namibian border should be on the ‘highest alert’ due to a flood wave expected from South Africa, Chief Hydrologist Guido van Langenhove said yesterday, while the water level on the Okavango River in the northeast is rising towards the eight-metre mark.

‘According to information from the Department of Water Affairs (DWA) of South Africa, the Bloemhof Dam was this [yesterday] morning 118.1 per cent full and releases from sluices were stepped up to 3 200 cubic metres per second,’ Van Langenhove said yesterday in his daily update on river levels. ‘A flood wave is now moving down the lower Orange River. Because of the gradual stepping up of the releases, the water levels and flows will increase over a period of about a week. The first rise in water levels was reported at Upington, South Africa on Saturday morning. The flood is expected to arrive at Noordoewer this morning. ‘It is difficult to assess what areas along the river will be inundated and what other damage and disruption the flood wave may cause, but people along the lower Orange River should be on the highest alert,’ Van Langenhove said.Towards the end of this week, the water level at Namibia’s Noordoewer bridge may rise from the normal 50 centimetres or 1 m to above 7 metres, he warned. ‘The last comparable releases from the Bloemhof Dam were 2 400 cubic metres per second in 1996.’The maximum inflow for the Bloemhof Dam has been 3 500 cubic metres per second at times in the past few days. Rains in the catchment area of the Vaal River, which flows into the Orange, are abating, and the situation would return to normal in the week to come for the upper Orange River, he added. Meanwhile, the Okavango River had reached a level of 7,65 m by noon yesterday, 9 cm up from Saturday. A year ago it stood at 5,06 m and the average level for that date is 4,91 m.’The hydrological conditions are such that even normal rainfalls may cause high flood waves now, and the highest alert is advised,’ Van Langenhove warned.The earlier high rains in the lower catchment of the Okavango in southern Angola are still pushing up the river’s levels at Rundu but seemed to stabilise yesterday morning, according to Van Langenhove. ‘It is unfortunately still difficult for our Angolan colleagues at Menongue to collect and forward precise information.’ For comparison, previous higher levels on record for January 31 were 7,89 m in 1962, a staggering 8,69 m in 1968 and back to 7,66 m in 2004.In 2009, the Okavango reached a record level of 8,65 m.