We even measure the level of the River Nile to see how much flooding we can expect. We have three seasons: Akhet, the flooding season, Peret, the growing season and Shemu, the harvesting season.

MANIAL SULTAN, Egypt — Yassin Saeed remembers when the Nile’s annual flood drenched his village in the years before the construction of the Aswan High Dam. Now, former flood lands are green fi ...