In Africa, locals have formed a close connection with their lakes and rivers over millennia. People live in villages along great bodies of water, such as Lake Turkana, which straddles Kenya and Ethiopia. Local fishers rely on the catch they get from the lake’s jade-coloured waters, and children play in the shallows, wary of crocodiles and hippos. The adage of freshwater being a precious source of life takes on a whole new meaning in the case of Lake Turkana, the world’s largest permanent desert lake.

Country
Kenya and Ethiopia

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Challenge

Lake Turkana and its river basins, including that of the Omo River, are vital for the people, economies and wildlife of both Kenya and Ethiopia. The Omo River delta and Lake Turkana are rich in biodiversity, support endangered species such as flamingo, and its fish are important to the local economy.

The region around Lake Turkana is vulnerable to drought. In recent times, concerns have grown about low lake levels due to climate change and the damming of one of the lake’s main inflows, the Omo River, which originates in Ethiopia and empties into the northern part of the lake.

It was, therefore, a surprise to many when devasting floods1 hit lakeside settlements in 2020, damaging the livelihoods of thousands of people, destroying homes, and affecting wildlife.

The landscape around Lake Turkana, Kenya © AdobeStock/Moiz

However, a recent study by the UNEP-DHI Centre, on behalf of the United Nations Environment Programme (UNEP), indicates that such floods may become a more regular occurrence in years to come. It found that climate change could increase the likelihood of both drought and flooding around Lake Turkana due to erratic precipitation, and that livelihoods could be affected if no adaptation measures are implemented. Deforestation and cultivation on steep slopes have already led to landslides, flooding and land degradation.

The study proposed a number of measures to address the situation, but not all are easy to implement. One example is to improve the dialogue between Ethiopia and Kenya so both nations see the mutual benefits of managing the Omo River collaboratively.

Through this study, we are able to demonstrate how to use scientific evidence to validate or challenge prevailing theories and to show that win-win scenarios can be achieved via close collaboration, both at the technical expert and decision-maker levels. UNEP is now in a better position to support cross-border dialogue between Ethiopia and Kenya. The local authorities involved in the project strengthened their ability to study environmental issues in their catchment and the root causes of those issues. They also learnt how to test the benefits of different solutions.

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Joakim Harlin, Chief of Freshwater Ecosystems
United Nations Environment Programme (UNEP)

About our partner

Since its inception in 1972, the United Nations Environment Programme (UNEP) has been the global authority that sets the environmental agenda, promotes the coherent implementation of the environmental dimension of sustainable development within the United Nations system and serves as an authoritative advocate for the global environment.

About the UNEP-DHI Centre

UNEP-DHI Centre is a UNEP centre of expertise on water and environmental issues. The centre provides key technical support to UNEP’s role in assisting countries to achieve their sustainability ambitions.

No natural outlet

One of the reasons Lake Turkana is so vulnerable to flooding is that it has no natural outlet, which makes it prone to changes during increased and decreased inflow. The largest inflow comes from the Omo River and its tributaries in Ethiopia. In recent years, the natural river inflow has been thought to be affected by large-scale dam development in Ethiopia. The dams generate electricity and facilitate agricultural production which Ethiopia regards as essential for its development.

Solution

Studies, such as the UNEP-DHI Centre study, can be a critical first step in identifying and quantifying the root causes of flooding. The study sought to:

  • Establish a joint scientific understanding of the lake and its river basins
  • Set up a monitoring system for Lake Turkana and its river basins
  • Evaluate scenarios to tackle the specific issues and hotspots identified, combining water resources developments, rehabilitation and adaptation measures, and climate change projections
  • Implement pilot demonstrations for ecosystem rehabilitation

Based on detailed scenario modelling, the work undertaken generated elements to support dialogue and water diplomacy between the two nations. This included the identification of possible initiatives that could help mitigate the effects of climate change, such as the building of barriers around the lake to help prevent flooding.

One scenario demonstrated that it is possible to maintain and even improve hydropower production in Ethiopia while achieving a certain balance in Lake Turkana water levels. This would require that Ethiopia develop alternative power sources for the dry season. If this were possible, it would provide a way to meet some of the ecological requirements of Lake Turkana and the surrounding area while respecting Ethiopia’s need for hydropower.

Another example of scenario modelling focused on reforestation, soil and water conservation. The aim was to assess how reforestation, agroforestry, and soil and water conservation measures may reduce flooding, soil erosion and landslides. The conclusion was that ‘reforestation, agroforestry and soil and water have an impact on the water balance, the path the water takes, as well as soil and nutrient balances.’2 Downstream, ‘the risk of flash floods and flooding in general are considerably reduced’ and there would be ‘a clear improvement of the water quality in the rivers downstream, including less turbidity and less E. coli.’3

Results

Countries such as Ethiopia and Kenya that share water bodies can benefit from cooperation that can have a positive impact on the basin, the ecosystem, the economy and people.

Ethiopia and Kenya now have access to planning and water resource management scenarios that translate into win-win situations and represent a better way forward for the Omo-Turkana Basin.

Increased irrigation and other abstractions within the basin may help to counterbalance increasing water levels in Lake Turkana due to climate change

It may be possible to partly reproduce seasonal inflows to Lake Turkana that can maintain fish and hydropower production in the basin

Soil and water conservation and reforestation measures can significantly reduce the risk of landslides and mudflows

Solution deep dive

A key purpose of this project was to try to quantify the impacts of rehabilitation and adaptation measures, planned upstream water resources development activities and possible impacts of climate change. The aim was to provide a common set of data and information resources to facilitate transboundary collaboration in the basin. Water resources modelling was an essential tool.

A user-friendly web portal with dedicated applications allowed stakeholders, the local authorities, to contribute to and follow every step of the project journey. All these things facilitated communication and knowledge-sharing and generated fruitful engagement and consultation.

The ‘superstar’ was the Planning app, which enabled stakeholders to analyse the trade-offs between selected project scenarios, using an indicator framework proposed by the project team and discussed with the stakeholders.

Highlights of how we did it

  • Establishing the Transboundary Monitoring Observatory portal: DHI’s Water Tools were used to establish the Transboundary Monitoring Observatory (TMO) portal. It is available to all stakeholders and decision-makers and contains five different applications: Data Monitor, Root Cause Analysis, Indicators, Planning and Document
Agriculture, energy, water resources and water supply and sanitation investments at the basin level as depicted in the Planning app. Key result plots for six indicators: total hydropower production, perennial sugar cane production, fish catch vs water level, inundated settlements in Lake Turkana, mean annual fluctuation of Lake Turkana water level, % of years with severe water level of Lake Turkana. There is a wide collection of indicators available per sector, namely: agriculture, economy, energy, environment, fishery, social welfare, water resources and water supply and sanitation.
  • Setting up basin models focusing on development and rehabilitation: MIKE HYDRO Basin was the water resources modelling software applied to set up the basin models focusing on development and rehabilitation. A baseline model was established. A number of scenarios, which took climate change into account, were set up.
Interface of the MIKE HYDRO Basin baseline model. In total, two water resources development scenarios were set up (2025 and 2040), two climate change scenarios (RCP 4.5 and RCP 8.5 2046-2065 projection period), and four different rehabilitation and adaptation intervention scenarios. The Planning app was used to compare these scenarios.

Key results

  • UNEP is in a better position to support cross-border dialogue between Ethiopia and Kenya
  • The stakeholders involved in the project strengthened their ability to study environmental issues in their catchments; root causes behind those issues; options for monitoring, including the use of remote sensing data; and how to use an indicator framework to test the benefits of different solutions for water resource planning
  • Scientific evidence was used to validate or challenge prevailing theories and it was demonstrated that win-win scenarios can be achieved via close collaboration both at the technical expert and decision-maker levels

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