THIS is with reference to the article ‘Disrupted rhythms of the Indus’ (June 18) which has presented a very simplistic view of the Indus and the irrigation system built around it. The human interventions were made necessary due to two basic aspects – to increase the size of fertile land in the valley, and to control the river’s erratic behaviour. In its natural form, the reach of the Indus and its few naturally-flowing ‘inundation or flood canals’ was limited, which was unable to meet the growing demand for food in the region. Then, due to constant variations in rainfall and other climate-related factors, the Indus valley fluctuated between dry and flood seasons.