Nilometers were used to control the changes in the water levels of the Nile. Used together with charts of average levels, the changes of the coming weeks could be predicted. Important both to prepare for great floods, drought and determining the taxation levels. Tanis has many nilometers. I don't really know why. Perhaps there were groups competing with each other on the predictions. The nilometers here are among the best preserved non-religious structures of Tanis, thanks to using stone in the structure. Unfortunately, none of the many caretakers here have taken interest in clearing them from garbage.
