The Nilometer of the Temple of Khnum (plaque number 7) is below the southern balustrade of the temple. Built in the 26th dynasty, the Nilometer's stone stairs lead down to a small basin for measuring the Nile’s maximum level. Another stairway, with a scale etched into its wall, leads to the water from the basin’s northern end.
Heavenly portents and priestly prophecies aside, in ancient times only the Nilometer could give a real indication of the likelihood of a bountiful harvest. When the Nilometer here in the southern frontier town recorded a high water level, it meant a good harvest, which in turn meant more taxes.