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World Bank funds the restoration of Kapichira dam in Malawi

The World Bank Group’s Inter­national Development Association (IDA) has approved US$ 44.7 million in funding to restore operation and increase resilience of the 129.6 MW Kapichira hydro dam in Mal­awi, which was severely damaged during tropical storm Ana in January of this year (see H&D Issue 2).

The funding, which was approved in June, is part of a US$ 60 million emergency power restoration project to be financed by the WBG, which also includes US$ 15.3 million for repairs to the southeastern African country’s transmission and distribution network. International contractors are expected to be hired within three months for the Kapi­chira works. An owner’s engineer will be hired to assist state-owned Elect­ricity Generation Company of Malawi (Egenco) with the Kapichira repairs.

Flash floods during the tropical storm Ana caused extensive damage to Kapichira’s dam and fuseplug resulting in the necessity to draw down the reservoir and putting the most downstream plant on the Shire river cascade out of operation. Kapichira, the country’s main source of electricity generation, represents almost 23 per cent of Malawi’s total installed capacity, and typically a third of its domestic generation. In 2021 the plant generated 670 GWh or 32 per cent of Malawi’s total generation.

In addition to returning to operation a key plant in the country’s power system, the restoration project aims to address key root causes that undermined the resilience of the damaged infrastructure. Based on preliminary assessments, carried out by Egenco and the World Bank, it is understood that ,at the time of the storm, only two of the five gates of Kapichira’s main spillway were open, and were only partly functional, so the capacity to evacuate flood waters was greatly reduced. This resulted in water rising in the reservoir and overtopping the dam crest before the fuseplug was washed away. There are several reasons for only two gates being operational, according to the World Bank’s project appraisal document. First, sediments had accumulated over time in the reservoir and constrained Egen­co’s capacity to operate the reservoir at higher water levels, and second, stoplogs, required for repairing the gates, were not high enough to protect the gates at these levels. Outages were planned to rehabilitate the gates, but the COVID 19 pandemic meant uninterrupted power was required for hospitals, so Egenco was prevented from undertaking maintenance and repairs at Kapichira.

The rehabilitation measures proposed therefore aim at strengthening technical elements, as well as operation and management capacity and procedures at Kapichira. The power restoration project will include rehabilitation of Kapichira’s dam and spillways, and improvements to the plant’s res­i­lience, in phases. Phase One works, which are already being implemented and funded by Egenco, include removing sediment from the reservoir, returning water levels to operational levels and developing a temporary cofferdam upstream of the damaged infrastructure (the fuseplug and damaged section of the embankment dam). This will prevent further damage, while protecting works for the second phase. Immediate actions mobilized by Egenco also include starting actions on the critical path for Kapichira dam rehabilitation, such as collecting topographic data, assessing the quality of sand available in the reservoir for construction, and beginning sediment management studies.

Phase One works are expected to be completed in November this year. Based on a revised design that would address key technical and operational features, which contributed to the failure. Phase Two work includes the rehabilitation of dam infrastructure and its upgrading to improve resilience (not­ably the main and emergency spillways), as well as support for operations and maintenance and sediment management. An international engineering consultant will be brought in as Owner’s Engineer for Egenco for Phase Two. Its recommendations will be implemented by a contractor also to be procured by Egenco.

The project will also assess existing studies and modelling to support the design of a basin-wide sediment management strategy for the operation of the cascade of hydropower plants on the Shire river (existing and proposed reservoirs) and irrigation scheme.