| Africa


better managed to deliver stronger economies for both Zambia and Zimbabwe, and to make people happy on both sides of the river. President Hichilema added that he regrets that one of the two utilities is engaged in “excessive abstraction” of water to the disadvantage of the other, and there is a need to strengthen the authority of ZRA to ensure ZESCO and ZPC operate within their allocated framework for water usage. In the past, both power companies have exceeded their water allocation. In 2018 they were within theirs, but ZESCO exceeded this in 2019. Then from 2020-22 both power companies continued to use more than their allocation. However, last year, ZESCO exceeded by 0.42%, which is permitted under the Water Purchase Agreement, while ZPC exceeded by 11.12% and attracted applicable over-utilisation penalties. The river authority said the power companies


were advised to use water within their allocation so as to leave 6% live storage by the end of the year, to support power generation into the second quarter of 2023. However, over-utilisation and poor performance of Kariba lower catchment rivers led to low water levels being recorded and, as of 11 January 2023, the lake level was only 0.28m above the minimum operating level.


Until the end of January, ZRA said both ZESCO and ZPC needed to maintain Kariba’s combined average generation output at 500MW (250MW each) after which they could increase to 400MW per power station. The flows of the mainstream Zambezi River are set to further increase during February and March, with lake levels projected to significantly increase by April 2023 in line with peak flows of the river. Zambia’s President Hichilema doesn’t want to dwell on the past but wants to “see how we can do better going forward”. He also added there is a need to expedite repair works to the plunge pool at Lake Kariba to ensure the structural integrity of the over 60-year-old dam wall is maintained. The work is part of the ongoing US$294 million-dollar Kariba Dam Rehabilitation Project which started in 2017 and also includes refurbishment of six spillway gates. Looking to the future, ZRA said it wants to take full


control of the water intakes to the both Kariba power stations “in order to effectively regulate utilisation of water”. This will mean the immediate closure of inlet valves as soon as water usage exceeds the acceptable threshold. There are also plans to review penalties for exceeding water allocation, while discussions are underway to speed up the development of upstream reservoirs, such as the Batoka Gorge hydroelectric scheme and Devils Gorge hydroelectric scheme, to improve operations and pursue synchronisation with other dam operators.


Grand Ethiopian Renaissance Dam Uncertainties surrounding climate change and its


impact on the management of the Nile River system has led to the development of a new analytical framework that can provide economic benefits for affected countries. Historically, water infrastructure projects have been constructed on the Nile for water supply, flood control and hydropower generation purposes, mostly in Egypt, Sudan and Ethiopia. Over the past two decades, Ethiopia has been increasing its use of the Nile for


www.waterpowermagazine.com | March 2023 | 21


hydropower generation and the construction of the Grand Ethiopian Renaissance Dam (GERD) on the Nile near the Ethiopian–Sudanese border. The dam is expected to result in a range of opportunities and risks to Sudan and Egypt, triggering political tension between the three countries. Negotiations have so far failed to reach agreements over how to fill the reservoir and water sharing during times of drought, while concerns centre on the fact that the total storage capacity of the GERD is equivalent to 1.5 times the historical mean annual river flow at the dam location. Indeed, negotiations have not even considered the impact of climate change. Research led by The University of Manchester and published in Nature Climate Change has developed a unique river modelling software which combines climate projections; hydrological, river system and economy-wide simulators; and artificial intelligence multi-objective design and machine learning algorithms to design adaptive plans for various climate change situations.


Above: Kariba Dam is a 128m high double curvature concrete arch dam, situated in the Kariba Gorge of the Zambezi River between Zambia and Zimbabwe


Below: Low reservoir levels in the High Atlas Mountains of Morocco. Consecutive years of drought have impacted water f supplies across the region


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53