Step 1: Understanding the Concept:
The question asks to identify a Harappan site where evidence of canal irrigation has been discovered. While the Harappans were known for water management (wells, reservoirs, drains), large-scale canal irrigation was not found at most major urban centers.
Step 2: Detailed Explanation:
(1) Shortughai in Afghanistan: This site was a Harappan trading outpost, likely established to control the trade in lapis lazuli. Being located in a semi-arid region, agriculture would have depended on irrigation. Archaeologists have found clear evidence of irrigation canals near this site, which is a unique feature compared to sites in the Indus basin.
(2) Banawali in Haryana: This site is notable for its radial street plan and a terracotta model of a plough, but not for canals.
(3) Harappa and (4) Mohenjodaro: These great cities had sophisticated wells and drainage systems for water supply and sanitation, but direct archaeological evidence for large irrigation canals is absent. It is generally believed that agriculture in the river valleys relied on seasonal floods.
Step 3: Final Answer:
Shortughai in Afghanistan is the Harappan site where clear traces of canals have been found.