Ethiopia should lower the height of its Renaissance saddle dam to defuse the water crisis, says Nader Noureddine.
The first stage of Ethiopia’s Grand Renaissance dam project is fast approaching its end. At 70 metres high, the dam is just 25 metres shy of the target for this stage of the project. Come June, it will be able to store the 14 billion cubic metres (BCM) of river water needed to kick the first turbines into action. 
With two out of the 16 planned turbines up and running, the dam will generate 700 megawatts of electricity per year. And by late 2017, all turbines will produce 6,000 megawatts of power, drawing on a reservoir of up to 74.5 billion cubic metres. The dam will be 145 metres tall — one and a half times the height of Victoria Falls on the Zambia-Zimbabwe border.
For the people of Egypt who live downstream, there is an overwhelming sense of anxiety about the heavy price they will pay for the dam in years to come — and the price they are paying even now.
Apprehension has been growing among Egyptians that Ethiopia is already storing water in the Renaissance reservoir, ahead of schedule. Ethiopia had diverted the Blue Nile in order to build the dam. To re-divert the water back to its original course, the most reasonable course of action would have been to wait for the next flood. But instead Ethiopia did this on 26 December, passing the water through the dam — meaning it might already be storing water.
There have now been nine years of drought, with nothing to herald the arrival of a heavy flood in 2016, according to the Intergovernmental Panel on Climate Change projections from 2007 and 2008. [2, 3] Given that rainfall over the Ethiopian headwaters has decreased by 70 per cent in the past nine years — surpassing the previous record of seven years — Ethiopia should not have begun storing water.
It should also have waited for the first heavy flood of this year to allow the three Sudanese Nile dams to be filled first, even partially. These dams have stopped operating due to severe water shortages caused by the record drought and weak water flow from Ethiopia. 
In the ongoing negotiations between the three countries, the most recent of which ended on 11 February, Ethiopia has raised three no’s in the face of the Egyptian negotiator: no to talks about stopping the work at the dam; no to negotiations about dam specifications, height and storage capacity; and no to talks about dividing water quotas with Egypt and Sudan. Unfortunately the Egyptian negotiator committed a strategic error by accepting these terms.
Ethiopia has raised three no’s in the face of the Egyptian negotiator:
No to talks about stopping the work at the dam
No to negotiations about dam specifications, height and storage capacity
No to talks about dividing water quotas with Egypt and Sudan
Given all this, I cannot help but think that Ethiopia’s main objective for building the dam goes far beyond energy generation and agricultural development. It is to control — by agreement or sale — the amount of water that is pumped into Egypt.
This theory is supported by the dam’s meagre power generation capacity. Asfaw Beyene, an Ethiopian-American professor of mechanical engineering at San Diego State University, United States, rejects Ethiopia’s stated electricity production target of 6,000 MW, saying he doubts it will even hit 2,000 MW. He adds that the dam’s huge size and poor adherence to safety regulations make it susceptible to collapsing: once or twice every 20 years, heavy flooding will push the reservoir up to 100 billion cubic metres, a quarter more than it is built to hold.
Faced with Ethiopia’s three no’s, Egypt was forced to negotiate marginal matters rather than the essentials: keeping its water quota the same as at pre-dam levels, and ensuring minimum daily or annual water flow through the dam. It has both failed to secure its water quota and to secure guarantees between the three countries with written, binding treaties rather than oral statements about causing no harm.
Ethiopia’s argument is that they cannot pledge a specific water quota for Egypt because the Blue Nile water flow varies by the year. But this is a deceptive argument: water experts know that states deal with river flows based on an average annual figure, calculated through consecutive 100-year blocs, not year by year.
The average annual flow of the Blue Nile is calculated at 50 billion cubic metres — the basis of the agreement that downstream countries are pushing for. Because the Renaissance dam reservoir will prevent annual fluctuations, the reservoir behind the dam — about 75 BCM in size — could enable Ethiopia to meet the requested water quota.
Sudan switches sides
Another reason for the growing apprehension among Egyptians is Ethiopia’s creation of a split in the Egyptian-Sudanese alliance. The 1959 Nile water sharing convention explicitly stated that Egypt and Sudan would act as a single unit, or vote, when negotiating with headwater states — those home to the Nile’s sources — on dams or water quotas.  Nowadays, though, Sudan defends the Ethiopian dam more than Ethiopia itself.
On the Ethiopian side there seems to be a strategy of never-ending negotiations and non-stop construction. And Ethiopia has attempted to woo Sudan, as if it were constructing the dam for its benefit.
Grand Ethiopian Renaissance dam project. Facts:
The dam is located on the Blue Nile about 20 miles from the Sudan border
It’s 145m high and 1,708m long
It floods an area of 1,680 sq km
It holds about 75 billion cubic metres of water
Source: Ethiopia Electric Power Corporation
But Sudan will face problems unless it pushes for answers to the important question: what will Ethiopia do to prevent the enormous amount of silt that will pile up behind the dam — estimated at 136.5 million tons annually — from reaching the Sudanese reservoirs? This silt alone can block the dam entirely within 50 years.
One solution is to construct more saddle dams — a strategy to help retain silt and extend the life of the Renaissance dam to 200 years.  But evaporation from the reservoirs of these new dams will wipe out what is equivalent to half the water quotas of Egypt and Sudan!  So is there another solution?
Unless action is taken, water wars could break out in the region. But there is a solution which will satisfy all parties and hopefully prevent conflict from erupting between the three countries.
This solution lies in Renaissance’s rock-filled saddle dam. The saddle — or auxiliary dam — adds 60 billion cubic metres of water to the main dam that generates electricity. The height of the saddle dam is now 45 meters. Reducing it by half would also cut the storage capacity of the dam’s reservoir by half, down to approximately 30 BCM. This would restore water flow, reduce evaporation and slow down the build-up of silt — all without any impact on energy production.
This is bound to reduce the likelihood that extra saddle dams will be built. Even if another is needed, building one with a lower storage capacity will not dramatically affect water flow downstream — and this makes it a solution that Egypt and Sudan would more easily accept.
Nader Noureddine is a professor of water resources and land reclamation at Cairo University, Egypt.
This article was originally published in Arabic on SciDev.Net’s Middle East and North Africa edition.