I magine yourself as a bird soaring high up in the sky. Your bird’s-eye view of the unfolding landscape far below includes a silvery ribbon meandering along mountain slopes. You follow this ribbon as it gets wider and wider and then breaks up into several tributaries before it finally gets swallowed up by the ocean. Yes, this shimmering ribbon is a river. It may have been born from a tiny spring gushing out of the earth or from the melting snows of mountain peaks.
Rivers, as you know, have made history. They have given birth to civilisations like those on the banks of the Indus. They have been a source of food and livelihood and also offer a myriad of benefits such as transportation, irrigation and others. For this reason, Indians revere our rivers. But rivers also help in other ways that we tend to overlook. They give rise to mangrove forests and wetlands, and support a plethora of life. The rich biodiversity around rivers helps control climate change. Humans tend to use our intelligence to modify the natural resources around us. So, we build dams across rivers. These huge reservoirs of water help generate electricity, store excess rainwater, and prevent flooding of the neighbouring land. But dams also change the riverine ecosystem and drastically alter the environment downstream. The river undergoes physical, chemical and biological changes. Can you guess how?
