3 minute read
Paul Block. PhD
A GERD Water Sharing Policy: In the Eyes of Foreign Expert
By ABN staff writer
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Dr. Paul Block has been developing a water policy specifically for the GERD that gets conditioned on natural hydrologic variability. “When we think
about water security, we think about water scarcity. Even within the Nile basin, there are very different priorities and contexts we need to remember and
take account of” he says.
In downstream countries particularly Egypt the challenge is a physical water scarcity. Whereas for the upstream countries, the focus is much more on economic water scarcity and that is perhaps the lack of development of infrastructure to take advantage of.
One of Kevin Wheeler papers shows there are periods where flows are naturally high and some years. And some periods where flows are average and some are low. This has been the context for hundreds and thousands of years and the countries have been subjected to these natural variability. Where the renaissance dam is located most of the variability happens July to October.
Before the GERD exists, if there is a large amount of stream flow in some year all of that stream flow is passed down the stream. Likewise, if a small amount of stream flow passes leaving Ethiopia and going into Egypt and a small amount passes downstream.
“It is a policy that explicitly takes into account natural hydrologic variability and shares that variability and those risks among all the countries.
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This is not a policy that explicitly favors Ethiopia, Sudan or Egypt. But explicitly shares these risks among the countries”
Washington’ policy (based on inflow and reservoir volume; droughts) has implications for reservoir operations, Inflow 20bcmand water level 618m, releases 9.7 for a total of 29.07bcm is based on inflow reservoir volume, the height of the reservoir and releases and it has a drought focus.
What happens in through this policy is for years when flows are low; the reservoir depending on its level would supplement that flow downstream. This has real implications on how the reservoir then is operated and maybe operated in a certain way. This is based on what is going to be expected of coming in and on how much will be released from the reservoir storage.
Unlike the Washington policy, an alternative water sharing policy Dr. Paul Block proposes is a long-term operating policy that firstly better shares hydrologic variability and secondly gives Ethiopia sovereignty over GERD operations.
'It is a policy that explicitly takes into account natural hydrologic variability and shares that variability and those risks among all the countries. This is not a policy that explicitly favors Ethiopia, Sudan or Egypt. But explicitly shares these risks among the countries' he explains.
The two main tradeoffs considered here are upstream hydropower that is in Ethiopia and downstream flows for Sudan and Egypt. For lower flows below the historical average the renaissance
Paul Block PhD
University of Wisconsin Madison/USA/
dam is able to supplement downstream and this is not based on reservoir levels operating policy but the way this assimilation optimization works. It is possible to look at different risk thresholds depending on how many one wants to try to capture.
One that would really focus on maximizing hydropower may look where inflow essentially matches releases and follows the historical conditions up to the long term average. Moreover, the excess could be stored in the renaissance dam. ‘Hence, it moves away a little bit from focusing on reservoir levels and operations of the GERD and instead focuses just on inflow and releases. It would allow Ethiopia more sovereignty on how the country would choose to operate the reservoir as long as it is meeting these policies.’ Dr. Block concludes.
