Measuring the river for the farm

This lesson asks you to identify and describe factors that can contribute to economic development. The museum offers one record: measuring a river's flood, through the Nilometer, which its source says was essential in setting irrigation policy. The record does not say that this raised output or the economy; that link is your class's inference to make and defend. Other factors are for your class to bring. ¹

Think about what information a farming society needs in advance, who collects it, and who uses it.

The Nilometer is a stone-lined pit, circular at the bottom and rectangular at the top, linked to the Nile on its east side by three lateral tunnels at different levels ². At the centre stands an octagonal marble measuring column; it is divided into nineteen cubits, and the sixteenth-cubit mark stands for the ideal flood level ². It measured the height of the Nile waters during the annual flood, and its readings were essential in setting irrigation policy ³. Ahmad ibn Tulun restored it in 872-873 and removed the caliph al-Mutawakkil's name from a band of Kufic inscription; Yeomans reads this as a wish to dissociate himself and Egypt from the Abbasid caliphate ².

Yeomans says the readings were essential in setting irrigation policy, and the record does not say what the policy was or who gained from it. If the sixteenth cubit is the ideal flood level, what decisions about water and farmland might a ruler base on a reading far below or far above it, and what would you need to know before calling those decisions fair?

• The Nilometer of Rawda Island: the pit, the tunnels and the column.
• Ahmad ibn Tulun: who restored it among his water projects.
• Al-Mutawakkil: the caliph who commissioned it.

Read the Nilometer of Rawda Island. Draw the pit and its column, and label what is measured and what decision the record says depends on the reading.