Answering the land with water works

This lesson asks you to describe how people have answered the challenges and opportunities of the physical environment, to look at short-term and long-term effects, and to describe human activities such as dams and canals that create and change water bodies and systems. The curriculum asks for examples from around the world; the museum offers a few from the Islamic world, and your class adds the rest. ¹

Look at what each water work set out to do, then ask what it changed in the short term and in the long term. Compare a work that served for a long time with one that failed.

Al-Baladhuri reports that Umar ibn al-Khattab (may God be pleased with him) ordered Abu Musa al-Ash'ari to dig a canal for the people of Basra, and that the length of the Ubulla canal reached four farsakhs ². Before it, he says, people used to drink from the monastery of Qawaws on the Tigris ². Later the part between Basra and al-Hayri, about a farsakh, was blocked up. Ziyad, who was in the register under Abd Allah ibn Amir, advised that the digging be carried out, but was rebuffed; when Ibn Amir went out to Khurasan, Ziyad dug the canal from the point of blockage to Basra. When the water was let in, Abd al-Rahman ibn Abi Bakra, to whom the work was entrusted, began to race his horse with the water almost outrunning it. Ibn Amir was angry when he came and told Ziyad that he had meant to take the credit for the canal from him; the two drew apart until both died ².

It is easy to read a surveying manual as the start of the channels it surveys. The 2020 study places qanats in traditions far older than Karaji and discusses their earlier spread; it does not credit him with creating the system ³. The red heading on 26r of a later manuscript introduces levels the text says the author devised. That is an attribution within the transmitted work, not an examination of apparatus from his workshop, as the record on al-Karaji's levelling puts it ⁴.

Ibn Amir was angry because he thought Ziyad meant to take the credit for the canal, yet the water reached the people of Basra whoever was remembered for it. When we judge a water work, which matters more, who is remembered for it or who gets the water, and why?

• The digging of the Ubulla canal: the blocked stretch, the horse that raced the water, and the quarrel over credit.
• The Marib Dam: a great dam of ancient Yemen, and what happened when breaches began to appear.
• Al-Karaji's levelling methods: how a manual follows water from the search for it to the handing over of the work.

Read about the Marib Dam and the digging of the Ubulla Canal, then at Al-Karaji's levelling methods. Make two columns: what each work was meant to do, and what could change for the people living near it.