In a related trend, recent research has found that peak flows in the Ganges River basin are decreasing drastically. This basin is an irreplaceable water supply for over 18 million people. Sai Kiran Kuntla and his team of international researchers recently released a fascinating study in the journal npj Natural Hazards. From the outset, they highlighted the major downward trend in river discharge throughout India. The study finds that the peak outflow in the western and central Ganges River basin has decreased at a rate of 17% per decade. This continued decline presents disastrous implications for irrigation, domestic water supply, and hydropower production.
It is based on detailed time series data of discharge collected from 173 gauging stations on all the major river basins in India. The study examines river discharge trends for 1970–2010. These findings show that peak flows were substantially reduced at 74% of these stations. This trend is part of a systemic shift in hydrological patterns in the region.
Key Contributors to the Study
The research team is loaded with heavy hitters. In the first group are Ashish Sharma, a professor of civil and environmental engineering at the University of New South Wales, and Sharad Jain, a professor at Indian Institute of Technology in Roorkee. Justly so, as their combined expertise provides a strong foundation for the study’s conclusions about the shifting dynamics of riverine floods in India.
Kuntla emphasizes the urgency of these findings: “Our study provides updated insights into how flood behavior is changing across India—both in terms of intensity and timing.” This shift underscores the need for adaptive management strategies to align with evolving climatic conditions, as traditional water management practices may no longer suffice.
“Such findings help bridge the gap between scientific knowledge and actionable planning, particularly as climate change alters flood risks.” – Sai Kiran Kuntla
Alongside Kuntla, co-author Manabendra Saharia is drawing attention to the need for urgent action. He stated, “Translating these insights into updated reservoir rules, urban drainage designs, and drought-relief plans is now urgent if we want India’s water infrastructure to stay one step ahead of a changing climate.”
Impacts on Water Supply and Agriculture
This drop in peak flows is especially troubling for regions that depend, to a large extent, on monsoonal rainfall. The study revealed structural and anthropogenic changes across the drought-prone Deccan plateau. Peak flows during the monsoon season decreased by 8% per decade, while pre-monsoon peaks declined by a worrisome 31% on average per decade. This significant cut will undoubtedly have repercussions on U.S. agricultural output as well as domestic water supply.
“These inflows are essential for meeting irrigation, domestic water supply, and hydropower needs.” Without guaranteed deliveries, communities could find themselves in short supply at the height of growing seasons or critical power generation times.
M K Roxy, a climate scientist at the Indian Institute of Tropical Meteorology in Pune, emphasizes the influence of shifting rainfall patterns. These shifts are at the heart of the most pressing crises we’re experiencing today. He remarked, “Instead of steady, moderate rainfall across the season, we now see longer dry spells broken by short, intense downpours.” This unstable precipitation cycle makes controlling water more challenging. It not only increases the likelihood of flooding during intense storms,
Dams and Climate Change as Contributing Factors
The study’s authors further explain that the decrease in peak flows is attributed to a variety of influences, including dam building. In the Narmada basin, for instance, an increase in damming over the same time period has drastically changed the natural flow patterns. As Ashish Sharma explained, “Peak outflows are a function of rainfall and soil moisture prior to rain.” Climate change is leading to reduced soil moisture from the combination of increased evaporation due to warming temperatures. This realization has huge ramifications for how we manage floods.
Roxy further elaborated on the effects of climate change on hydrology: “With temperatures on the rise, soil moisture is decreasing because of higher evaporation, and dry soil absorbs more water.” This growing reality means it’s time to rethink existing water management systems entirely, in order to respond to a new normal of environmental conditions.
“Our results signal a hydrologic regime that is becoming more erratic.” – Manabendra Saharia
As urbanization surges unabated throughout much of India, even limited rainfall can trigger catastrophic flooding disasters. With climate change, Roxy warned that this trend would worsen familiar vulnerabilities in our cities that still have a lot of pavement with no proper drainage infrastructure.