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Sifelani Tsiko Agric, Environment & Innovations Editor
There are no plans to open floodgates of Kariba Dam reservoir as of now despite improving inflows into the waterbody which is now above the minimum operating level of 475.50 metres, the Zambezi River Authority says.

The Authority’s chief executive Eng. Munyaradzi Munodawafa said it could take more inflows for the waterbody to touch its full capacity.

“The lake current level recorded on 2nd March 2021 of 480.76m does not warrant any need for spilling. As is the case for dams with the design such as that of Kariba dam, there is a Rule Curve under the Standing Operating Procedures (SOP) for Kariba dam that governs Kariba reservoir operations and guides as to when spilling would be required,” he said.

“The current lake level is way below the rule curve limits of maximum storage for this time of the year and therefore, this implies that there is room to store incoming floods in the reservoir. Therefore, as the lake level recorded on 2nd March 2021 falls way below the Rule Curve limit, the Authority will not undertake any spilling soon.”

A latest update from the Authority showed that its water elevation as at March 2, 2021 had risen to 480.76 meters.

“From the last update made on 19th January 2021, the lake levels have increased by a total of 3.96 meters from the lake level of 476.80m recorded on January 19th to a lake level of 480.76 meters recorded on 2nd March 2021,” the Authority said.

This has placed the lake level at 5.26m above the Minimum Operating Level (MOL) of 475.50m.

“The lake is not yet at its full capacity. When at full capacity, the lake level is 13m above the MOL with live storage at 100% with 65 billion cubic metres of usable water,” Eng. Munyaradzi Munodawafa said.

When faced with abnormal water levels at Lake Kariba, the Zambezi River Authority (ZRA) opens four spillway gates to forestall damage to the dam infrastructure.

This also takes into account downstream adverse effects to other river users in Mozambique and farming communities along the banks of Zambezi River.

The Kariba floodgates are usually opened where there are heavy rains in the Zambezi catchment area, particularly in Namibia and Angola.

The sluice gates were opened to relieve pressure in 2001, 2009, 2010 and 2011.

The dam wall with 6 flood gates was built between 1955 – 1959.