Early flood forecasting system for Incomati Basin
Lower Incomati Flood Risk Management
Water and Sanitation
Area of Expertise:
Climate Resilience Infrastructure Development Facility (CRIDF), DFID
2013 – 2017
The Incomati River Basin comprises 46 000 km² spanning South Africa, Swaziland and Mozambique and is home to more than 500 000 people.
The basin, particularly downstream in Mozambique, experiences frequent flooding. This results in considerable loss to the formal and informal economies. The impact of flooding is aggravated by a lack of resources to cope with disaster and a history of limited coordination in flood control and management.
As part of the Climate Resilient Infrastructure Development Facility (CRIDF), Genesis was engaged in the basin for three years to support holistic flood mitigation as the financial and economic adviser on the project. Specifically, our work in the final year was to evaluate various flood mitigation responses (FMRs) and recommend a way to proceed with the choice and financing of the infrastructure. Our work was integral in establishing the need for an early warning flood forecasting system (EWFFS) and its requirements for financial sustainability.
Genesis’s capping involvement on the project was a comprehensive economic analysis of the FMRs, which had emerged through a consultative process with stakeholders. These infrastructure interventions (dykes, bridges, etc.) involve the diversion of water away from key risk areas. As a result, some areas are better off, while others are worse off. An understanding of which areas are better and worse, as well as their associated economic values, is an important consideration in continuing with an intervention.
Genesis carried out a cost-benefit analysis (CBA) to assess whether investing in infrastructure was justified from a social-welfare perspective and to understand the distribution of benefits to stakeholders, the output of which led to a discussion on potential financing for the chosen investments. Genesis designed, championed and carried out an innovative and rigorous approach to this work, which is unique to any CBA we have carried out before.
As a first step, a thorough land-use map of the flood area was carried out. The land was categorised in formal and subsistence agriculture, residential areas and roads, among others. By comparing the flood-hazard rating, generated by the hydraulic model of the “do-nothing” scenario, with that under the FRM, a picture of the potential cost savings under various FMR strategies was established. Assigning an economic value to the potential cost savings for each land-type was then compared with the actual costs of the intervention to assess whether the FMR was an efficient use of funds.
The EWFFS has gone live and is available online and in real-time as a resource for decision-makers. The key project stakeholders include local government, the impacted community, the water utility and key private sector companies who are located in the areas impacted by flooding. The project is a case study for successful public-private partnership and collaboration to reduce the negative impact of flooding.
Genesis aided this value being unlocked through detailing the “value chain” (users and processes) of the system (from forecasting to mobilisation), understating its costs and demonstrating the expected tangible benefits that can be unlocked through providing decision-makers with an early warning system that can inform their disaster mitigation response. This galvanised stakeholder coordination and support for its operational costs
TOP PHOTOGRAPH: The site on the lower Incomati that floods frequently and has been the focus of one of the project's flood mitigation strategies.
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