The Nilometer was an ancient Egyptian invention that was used to measure the level of water of the Nile. The ability of ancient Egyptians to measure the Nile’s water level in different seasons of the year, most importantly the flood season, and use their measurements to calculate the available water and forecast the Nile’s floods allowed them to create an agricultural system that was one of the most important, if not the most important, pillars that gave rise to the glorious civilization of the ancient Egyptians.

The nilometer had different shapes. One of them was the vertical column, which is the shape of the nilometer that can be found on Rhoda Island in Cairo. In general, this vertical column was built into the water of the river to measure the level of the river’s water to calculate the taxes that would be imposed for the year. Although the nilometers were an invention of the ancient Egyptians, they continued to be built and used by the different rulers that succeeded them. It is agreed by most that the nilometer on Rhoda Island was built around 861. This nilometer has old writings carved into it that date back to around 873.

It is worth mentioning that the nilometers were used till the 1960s, before the construction of the High Dam of Aswan reduced the annual inundation of the Nile, making the nilometers obsolete.