Egypt, Ethiopia and Sudan have reached an initial settlement on the filling and operation of a mega dam being built on the River Nile.

A joint statement by the three countries, along with the US and the World Bank, says negotiators had agreed to fill the reservoir of the Grand Ethiopia Renaissance Dam during the rainy season between the months of July and August.

It however makes no discussion on the crux of the dispute, which is the speed with which to fill up the dam.

Ethiopia wants to do it in six years, but Egypt has proposed at least a 10-year period, fearing that a shorter span will affect the downstream flow of the River Nile, which it relies on for 90% of its water.

A final deal will be signed on 28-29 January, when Ministers from the three countries meet again in Washington.

The preliminary agreement, which was brokered by US Treasury Secretary and the World Bank President, takes into consideration Ethiopia’s needs for starting early generation of electricity, but also outlines mitigation measures for Egypt and Sudan in case of prolonged drought periods in the downstream countries.