<Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> The flooding of the Nile is the result of the yearly monsoon between May and August causing enormous precipitations on the Ethiopian Highlands whose summits reach heights of up to 4550 m (14,928 ft). Most of this rainwater is taken by the Blue Nile and by the Atbarah River into the Nile, a less important amount is flowing through the Sobat and the White Nile into the Nile . During this short period, those rivers contribute up to ninety percent of the water of the Nile and most of the sedimentation carried by it, but after the rainy season, dwindle to minor rivers . </P> <P> These facts were unknown to the ancient Egyptians who could only observe the rise and fall of the Nile waters . The flooding as such was foreseeable, its exact dates and levels could only be forecast on a short term basis by transmitting the gauge readings at Aswan to the lower parts of the kingdom where the data had to be converted to the local circumstances . Which was not foreseeable, of course, was the size of flooding and its total discharge . </P>

When did the nile river flood in ancient egypt