Infrastructure to enhance water, energy, food and environment services in coastal East Africa

Julien Harou, Professor of Water Management and Chair of Water Engineering at The University of Manchester, discusses new approaches for balancing development interventions in some of East Africa’s coastal river basins.

Development in Africa will require exploitation of natural resources in river basins, for example with new dams and irrigated areas. But what will be the cost to nature and those who depend on ecosystems for their livelihoods?

Professor Julien Harou is engaging with these questions as Research Director of Manchester’s FutureDAMS (Future Design and Assessment of water-energy-food-environment Mega-Systems) project. Here, he discusses how partnerships with water planners in some of East Africa’s large coastal river basins led to a breakthrough collaborative approach for assessing and planning the development of these complex human-natural systems.

Development, but with what consequences?

Major river-basin development decisions require careful planning; they can involve large investments and long lifetimes, and may be irreversible. There is a strong argument for ensuring an appropriate balance of benefits and assessing resilience to future climate change.

Two river basins in Kenya and Tanzania that are essential national reservoirs of energy, food and ecosystem wealth exemplify the issues facing coastal East African regions. Tanzania’s Rufiji basin supports extensive socio-economic and environmental services and is targeted for major development via hydropower infrastructure (for example, the new Julius Nyerere Hydropower Project) and investment through the Southern Agricultural Growth Corridor of Tanzania.

In Kenya’s Tana river basin, in addition to hydropower and irrigated agriculture, ecosystem services include fishing on the seasonal floodplain, flood recession agriculture, reservoir fisheries, estuary fisheries, floodplain cattle grazing and sediment transport through the delta to the coast. Maintaining flood flows is important for Tana basin habitat regeneration and biodiversity needs, small-scale informal agriculture and livestock grazing.

In both cases planners should ask the question: will new water storage dams, or operations of existing ones aimed at energy and food production, displace essential ecosystem services and the livelihoods associated with them?

Achieving balance and resilience

In Kenya, The University of Manchester was part of the WISE-UP project, led by the International Union for the Conservation of Nature, which included University of Nairobi and Kenyan water management agencies. The work in Tanzania was part of the Natural Environment Research Council’s Future Climate for Africa Umfula project, working alongside Jomo Kenyatta University and the Rufiji water board. The projects involved local partners and aimed to enable water planning that involved stakeholders.

Both projects used river-basin simulation models to quantify how water availability across the basin over time impacts the provision of energy, food and ecosystem services. Artificial intelligence search algorithms then helped determine which combinations of development interventions create the most effective interactions between natural and built assets, and enabled the most appropriate trade-off between services.

The Tanzania project found that development that prioritises energy production adversely affects environmental performance downstream, although part of the negative impact can be minimised through release rules for the dam that are designed to replicate the natural variability of flow, without major sacrifice of hydropower. In Kenya's Tana river basin, work showed how controlled releases from multi-reservoir systems can be optimised to consider both provisioning ecosystem services (such as fisheries or grazing) and engineered services (such as water and power supply) at different locations and in different seasons. The projects also looked at how future systems would fare under a range of climate change scenarios, in an attempt to ensure any recommendations remain robust.

An interactive visual approach

A challenge of river-basin design with stakeholders lies in communicating how a large number of possible combinations of development interventions combine to produce cumulative impacts for different sectors and regions.

To support this, Manchester has created interactive online graphics to allow the many objectives and impacts of water development to be considered concurrently. This allows the implications of different development strategies for diverse stakeholders to be better understood. You can view a summary of how this works, including short films, on the WISE-UP project website.

Examples of how the interactive graphics can be interpreted to assist stakeholders to understand and assess interventions are found in our articles in Ecosystem Services (covering the Kenya project) and Earth’s Future (the Tanzania project).