Charles Ellicott Commentary Genesis 41:54

"And the seven years of famine began to come, according as Joseph had said: and there was famine in all lands; but in all the land of Egypt there was bread." — Genesis 41:54 (ASV)

The dearth. — As the Nile at this early period was not assisted and regulated in its overflow by dams and canals, famines were much more common in Egypt than they were later, after the kings had done a great deal to provide against this danger.

Since this dearth was also “in all lands”—including Arabia, Palestine, Ethiopia, and other regions—there was evidently a long period of excessive drought.

Egypt has always been susceptible to famine. For instance, Bar Hebræus (Chronicon, p. 260) provides terrible details of the sufferings in Egypt in the year of the Hejira 462. During that time, the loss of life was so great that in the city of Tanis (Zoan), where 300,000 men had paid poll-tax the previous year, fewer than one hundred souls remained at the end of the dearth.

One argument presented by Canon Cook, in his Excursus on the Bearings of Egyptian History on the Pentateuch, p. 451, for placing the Israelites' descent into Egypt in the reign of Amenemha III is that this monarch “first established a complete system of dykes, canals, locks, and reservoirs, by which the inundations of the Nile were henceforth regulated.”

The artificial lake of Moeris was also made by his orders, along with other works of extraordinary vastness.

Not only would such works likely be suggested by a dearth of unusually long duration, but the measures Joseph took during the seven years of famine would also place the country's entire resources at the Pharaoh’s disposal.