While the Nile River receded from the area long ago, workers in the ancient town of Thmuis, Egypt, digging the foundation of a water pumping station recently found a nilometer—a device that measured the river’s flood level and helped calculate taxes in ancient times.
Archaeologists who excavated the nilometer believe it was situated in a temple complex. They said the people of the time likely considered the river a god called Hapi, according to an article on the find in National Geographic.
Only about two dozen nilometers have ever been found. This one is in the ruins of Thmuis, an ancient Egyptian city in the Delta area. The Egyptian and American archaeologists who found it think the structure was built during the 3 rd century BC and that it was then in use for about 1,000 years. It calculated the level of the Nile during annual flooding.
The nilometer is a well that consists of a set of steps going down into the earth. It was constructed of large limestone blocks and was about 2.4 meters (8 feet) in diameter. Either the river reached to where the nilometer was, or it measured the water table as a proxy, National Geographic says.
The optimum height of the water during flooding was about 7 cubits, or 3.04 meters (about 10 feet).