Advancing integrated water storage to support the water–energy– food–ecosystems nexus in the Blue Nile Basin, Ethiopia

By Meron Teferi Taye, Girma Yimer Ebrahim, Jonathan Lautze, Abdulkarim Seid, and Yonas Tafesse

In the upper Blue Nile Basin, with its strong seasonal and often inter-annual variability of river discharge, any meaningful investment in the water–energy–food–ecosystems (WEFE) nexus needs to include water storage. Historically, though, decisions on water storage planning and management have not always drawn on a sufficient knowledge base. Information on water storage in ‘green infrastructure’ like groundwater aquifers has been particularly unclear, limiting the degree to which this resource could be actively considered in planning.

The CGIAR Initiative on NEXUS Gains has carried out research on options for addressing trade-offs across the WEFE nexus in the Tana-Beles Sub-basin (upper Blue Nile Basin) since 2022. A central premise of NEXUS Gains’ work on integrated water storage is that developing and managing grey (man-made) and green (natural) water storage in an integrated manner has the potential to maximize water use efficiency and minimize trade-offs. Unfortunately, no integrated water storage assessments have been conducted in the Tana-Beles Sub-basin to date, resulting in a critical knowledge constraint to maximizing benefits from such water storage options of the sub-basin.

To advance consideration of green infrastructure and foster greater integration of grey–green storage infrastructure, the International Water Management Institute (IWMI), together with partners, held a workshop in Hawassa, Ethiopia, 29–30 October 2024. The workshop attracted nearly 45 stakeholders from various sectors in the Blue Nile region of Ethiopia, including the Ministry of Water and Energy (MoWE), the Abay Basin Administration Office, universities, and the Environmental Protection Authority, among others. Key research results for enhancing the resilience of WEFE sectors through implementing integrated water storage were presented and discussed.

During his keynote speech, Dr. Michael Mehari, senior advisor with MoWE, stressed that the ministry believes the WEFE sectors are closely interlinked and interdependent and WEFE problems shouldn’t be addressed in isolation or at the expense of each other. He added that MoWE is promoting the application of WEFE agendas in its policy-driven watershed management works and small water pond development interventions.

Dr. Jonathan Lauze, the Initiative’s work package lead on integrated storage, outlined how NEXUS Gains can support MoWE’s objectives through its activities on integrated storage, and explained how NEXUS Gains strives to realize gains across the WEFE nexus in selected transboundary river basins (the Blue Nile and five other basins with water stress) by leading global nexus thinking and providing tools, guidelines, training, and facilitation for analysis and research for development.

New evidence on integrated water storage was also presented by IWMI researchers. Dr. Tewodros Assefa indicated the volumes of water that can be stored in five storage types in the Tana-Beles Sub-basin. Dr. Meron Teferi outlined the current gap in available water storage relative to demand for storage. She also identified how this gap will grow in the future, and challenged workshop participants to devise new approaches to fill the gap by drawing on grey–green storage infrastructure.

The WEFE nexus and integrated storage concepts were further discussed through panel discussions with experts from Ethiopia and Sudan and IWMI researchers. Debebe Deferso, integrated water resources management lead executive officer at MoWE and one of the panelists, said: “By providing estimates of water storage in all storage options, this work has supported our future planning toward integrated water storage.” Deferso further underscored that MoWE plans and implements grey–green storage types, and called on all water actors to exert their collective efforts for nurturing integrated water storage solutions under existing national stakeholder platforms, like the Multi-Stakeholder Platform and Water and Energy Sector Working Group.

Fekahmed Negash, an experienced water resources management consultant and another of the panelists, stated that integrated water storage is a new concept to Ethiopia and can be highly beneficial for realizing increased water availability, flood mitigation, and regulating river flows if effectively implemented in areas like the Tana-Beles Sub-basin.

Workshop delegates found that the new evidence presented was key to accelerating their progress toward the implementation of integrated water storage in the Tana-Beles. Birlew Abebe from the Abay Basin Administration Office noted that they will use storage demand projections to inform storage planning going forward. Ayelign Mesafint, deputy head of the Amhara Region Irrigation and Lowland Area Development, said: “I gained insightful knowledge on integrated water storage options and am committed to applying the evidence and experiences in my bureau’s regular work of irrigation dam planning and management, like research and design, operational plan development, and water release exercises.”

The workshop concluded after discussing the possible next steps that can be taken in the Blue Nile Basin to broaden the different storage options and their application.

The key messages that came out are:

• Integrated storage planning needs to account for temporally fluctuating volumes of stored waters as well as spatially inconsistent storage quantities. Therefore, the temporal and spatial variability of available water storage options needs to be understood so that areas of storage demand can be effectively linked to areas of storage supply.
• There is a need to set up a pilot project that demonstrates and documents the benefits of the integrated water storage approach.
• Coordinated dam operations, including Lake Tana and upstream dams, should be given emphasis in integrated storage management. Follow-up work on optimization of these and other storage types is needed to arrive at optimal scenarios through which nodes of storage demand link with storage supplies.
• Resource mapping of both the biophysical and social aspects, which must include stakeholders, is needed to properly implement the nexus approach.
• A coordination framework is needed to harmonize the efforts done by regional and federal entities. Supporting policy review, identifying gaps, and developing a regulatory framework for nexus policy to align with the current revised policies are important.

Meron Teferi Taye is Researcher – Transitioning Landscapes at IWMI; Girma Yimer Ebrahim is International Researcher – Hydrology and Water Resources, IWMI; Jonathan Lautze is Research Group Leader – Integrated Management of Basins and Aquifers, IWMI; Abdulkarim Seid is Country Representative – Ethiopia, Regional Representative – East Africa (Rotational CR); and Yonas Tafesse is Ethiopia Communications Consultant, IWMI.

This work was carried out under the CGIAR Initiative on NEXUS Gains, which is grateful for the support of CGIAR Trust Fund contributors: www.cgiar.org/funders

Header image: Participants at a workshop in Hawassa, Ethiopia, 29–30 October, 2024. Photo by IWMI.