Which risk increased in ancient Sumerian irrigation canals when the Euphrates River experienced prolonged drought?

💡 Explanation

When the Euphrates had prolonged droughts, the volume of water available for irrigation decreased, leading to increased evaporation, leaving behind salts dissolved in the river's water. This increased salt concentration in the irrigation canals lead to salt accumulation in the irrigated arable land. Therefore salt accumulation and land poisoning results, rather than sedimentation, collapse or infestation, each requiring other circumstances.

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