BENGALURU: Scientists from the Indian Institute of Science (IISc) have studied how changing climate and land use patterns will affect the flow of river Ganga, which will directly impact a major part of northern India.
The study, led by Prof Pradeep Mujumdar, was carried out by the Department of Civil Engineering at IISc.
Though both climate and land use affect stream flow, the effect of climate change was seen to be much more pronounced. Stream flow is a measure of how much water flows into a river or a stream and at what rate.
“Climatic changes introduce a large uncertainty in future water situations. Because of this, we need to bring resilience in our water management system by using more conservative methods. We need to base these methods on a worst case scenario and prepare ourselves,” says Mujumdar.
It’s hard to imagine an India without the river Ganga.
The 2,500-km long river, flowing through the states of Uttar Pradesh, Bihar and West Bengal, touches 44 per cent of India’s population. The Ganga basin accounts for 30 per cent of India’s cultivable land but there has been a lack of efforts to understand how the river is responding to changes along its basin.
The researchers studied about one-eighth of the total catchment area called the Upper Ganga Basin (about the size of Iceland).
They divided the study region, that also contained the origin of the river, into three different parts depending on topography, altitude and land use.
This region was a natural choice for the study because any changes observed in the stream flow here would be reflected in the entire river.
The researchers studied changes in land use through satellite imagery. Their analysis revealed that between 1973 and 2011, the area under cultivation increased by more than 20 per cent. During the same period, urban land also expanded significantly, though it occupied only a small area in the entire basin.
They also noted an appreciable drop in the area under forest cover. Such changes, the researchers say, are not at all surprising because between 2001 and 2011, the population of the region skyrocketed by 120 per cent.
Their predictions on future climate conditions indicated changes in rainfall patterns and a rise in the average minimum and maximum temperatures. The changing climatic conditions are expected to cause severe changes in water availability in the Upper Ganga Basin.