In good years, the flood was sufficient to cover the fields with the fertile silt that supported bumper crops.

In poor years, insufficient flood or excessive flood could devastate agriculture and threaten the food security of a civilization that had no significant means of importing grain from elsewhere.

The climate record for the Old Kingdom period — reconstructed from sediment cores, lake deposits, and other paleoclimatic proxies — shows that Egypt experienced relatively stable and productive conditions during most of the Old Kingdom.

The monsoon system that fed the Nile was reliable, and agricultural yields were high enough to support the surplus extraction that financed the pyramid complexes and the administrative apparatus that built them.