Estimation of evaporation from the Grand Ethiopian Renaissance Dam in the Nile Basin
Bachelor(2017) Rina UEDA
The Nile basin is very dry with few water resources, so that thewater from the Nile River is very valuable for downstream countries.
Egypt, which is located on the mostdownstream side, is dependent on the water from the Nile River.
In addition,Aswan High Dam in Egypt supplies water and electricity to the downstreamthroughout the year, supporting the economy and population of the Egyptianeconomy and the Nile Delta.
Recently, Ethiopia has been constructing the largest dam in Africa called the Grand Ethiopian Renaissance Dam at the upper reaches of the Blue Nile. It is expected that it will contribute greatly to the economic development in Ethiopia.
However, the Egyptian government is concerned that the Renaissance Dam will reduce water resources in Egypt.
Since the Renaissance Dam is a dam only for electricity generation, Ethiopia will not use the water itself from the Grand Ethiopian Renaissance Dam reservoir.
Grand Ethiopian Renaissance Dam
Cited from CCE NEWS(*1)
However, an enormous amount of water would evaporate from its reservoir. For example, the annual evaporation amount from Aswan High Dam in Egypt is 6% to 12% of the water storage amount.
Usually the evaporation amount is too large to ignore in the hot and dry areas as the Nile River basin.
Since the Renaissance Dam is located in amountainous area rather than a desert, the amount of evaporation might be notso large compared to Aswan High Dam.
It is said that there is a possibilitythat we can reduce the total amount of water evaporated from reservoirs ofAswan High Dam and Grand Ethiopian Renaissance Dam if we store a larger amountof water in the Renaissance Dam instead of storing water in Aswan High Dam.However, whether it is true has not been investigated.
This study aims to estimate the annual evaporation from thereservoir behind Grand Ethiopian Renaissance Dam and to investigate its impacton the Egypt.
We calculated the annual evaporation from14 lakes around the world using seven kinds of evaporation equation andcompared them.
As a result, the amount of evaporation from the Grand EthiopianRenaissance dam reservoir is investigated as 2.97 ㎢, which is equal to 5.1% of the flow rate from Aswan High Dam.
Thisevaporation volume is about 15 times of the volume of the Tokuyama Damreservoir, which is the largest dam in Japan.