Ganga's summer flow sustained by groundwater, not glacial melt: IIT Roorkee study
The study established the negligible role of glacier melt in maintaining the Ganga's summer flow, quantifying that beyond the Himalayan foothills, glacier-fed input is virtually absent and does not influence the summer discharge up to Patna. After Patna, tributaries such as the Ghaghara and Gandak become the dominant contributors, the study noted.
The findings were published in Hydrological Processes, a peer-reviewed American journal.
The study monitored river flow and its controlling factors such as evaporation loss, groundwater interaction, and the role of aquifer water levels in sustaining river flow. It employed isotope ratio (composition) techniques using a cavity ring-down spectrometer. Six laboratories, including one from Taiwan, assisted with various measurements required for the research.
Moreover, researchers found that in the upstream region of around 160 km, no significant change in isotopic composition was observed, indicating minimal evaporation due to the fast flow of water along a relatively steep gradient.
The negligible fluctuation in isotope values indicates limited interaction with groundwater, contrary to earlier satellite-based studies that warned of severe groundwater depletion across North India.
"In-situ groundwater level data show that the water table in the middle plain region of the Ganga has not changed significantly in recent decades to affect the summer base flow of the river. Our analysis shows that the Ganga is not drying because groundwater is depleting, but due to over-extraction, excessive diversion, and neglect of tributaries. Groundwater is still the hidden lifeline of the Ganga," said Professor Abhayanand Singh Maurya, lead author from the institute's Earth Sciences department.
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
NDTV
11 hours ago
- NDTV
Himalayas May Not Be Pristine Anymore, Study Shows Presence Of Toxic Metals In Clouds
The Himalayan clouds, once believed to offer purest drinking water, might be silently carrying toxic heavy metals, posing potential carcinogenic and non-carcinogenic health risks, especially to children. A new study has highlighted that the clouds over the Eastern Himalayas contain 1.5 times higher pollution levels than those over the Western Ghats. The study conducted by the Bose Institute, an autonomous body under the Department of Science and Technology (DST), identified significant levels of toxic metals such as cadmium (Cd), copper (Cu), and zinc (Zn) in non-precipitating clouds during the early monsoon season over the Western Ghats and Eastern Himalayas. For the study, scientists investigated the composition of heavy metals in the non-precipitating low-level clouds collected on the rooftop of the Indian Institute of Tropical Meteorology (IITM) in the Western Ghats and the Bose Institute campus located at Darjeeling in the Eastern Himalayas in 2022. "Children are at higher risk of 30 per cent of such toxic metals than adults in India. Inhalation of polluted clouds over Eastern Himalayas containing high concentrations of toxic metals is the most potential route for non-carcinogenic diseases," the study published in the journal Science Advances highlighted. "Health risk for the occurrence of carcinogenic diseases has increased due to inhalation of dissolved Cr present in clouds," it added. The scientists stated that the inhalation of polluted clouds over the Eastern Himalayas was identified as the main pathway for non-carcinogenic diseases. The study also found that carcinogenic risks have risen due to the inhalation of dissolved chromium present in clouds. The study linked elevated levels of cadmium, chromium, copper and zinc in the region's clouds to vehicular and industrial emissions from the foothills. They warned that clouds act as transport mediums for heavy metals, which can enter the body through breathing, skin exposure and consumption of rainwater in high-altitude areas. Despite the alarming findings, the study stated that the Indian clouds remain relatively less polluted compared to countries like China, Pakistan, Italy, and the United States.
India Today
15 hours ago
- India Today
Ganga river quietly loses over 50% of its water without us knowing. Here's how
A new study from the Indian Institute of Technology (IIT) Roorkee has revealed new insights into the hydrology of the Ganga River, shedding light on its summer flow and water loss dynamics as it leaves the by Professor Abhayanand S. Maurya, the research emphasises how the mighty river loses over half of its volume every year without anyone noticing team also discovered that groundwater, rather than glacial melt, is the primary source sustaining the Ganga's summer flow across the plains. Published in the journal Hydrological Processes, the study analysed two decades of extensive field data, challenging prevailing narratives driven largely by satellite observations of North India's groundwater to fears of widespread aquifer depletion, the research found that the central Ganga plain's groundwater system remains surprisingly stable. This stability is evident in the consistent output measured from thousands of shallow hand pumps, suggesting a robust and resilient underground water network still actively feeding the river. The study calls for renewed focus on restoring tributaries feeding the Ganga. (Photo: Getty) As the Ganga flows out of the Himalayas and into the plains, its volume notably increases by nearly 120 percent thanks to this reliable groundwater input. However, the research also uncovers a major and often overlooked issue: more than 58 percent of the river's water evaporates during the hot summer tremendous loss highlights the critical role of evaporation in diminishing the river's flow and underscores the urgency of addressing water conservation along the river findings carry significant implications for water resource management in the region, especially concerning aquifer recharge and tributary IIT Roorkee study led by Prof. Abhayanand S. Maurya reveals groundwater—not glacial melt—sustains Ganga's summer flow in the plains. Published in Hydrological Processes, it highlights the need for aquifer recharge & tributary revival.#IITRoorkee #GangaRiver #Hydrology IIT Roorkee (@iitroorkee) August 1, 2025The study calls for renewed focus on restoring tributaries feeding the Ganga and efforts to enhance groundwater recharge, ensuring continued flow during critical dry an era where climate change and human activity increasingly threaten water resources, this research not only redefines the understanding of Ganga's hydrology but also provides a scientific basis for sustainable river basin Professor Maurya points out, safeguarding the underground water system is essential to maintaining the health and heritage of one of India's most vital rivers. - EndsMust Watch
Hans India
a day ago
- Hans India
Groundwater dominates Ganga's flow in plains, not glacier melts: IIT Roorkee study
New Delhi: The river Ganga is primarily sustained by groundwater discharge, not glacial melt as widely believed, according to a study led by researchers at the Indian Institute of Technology (IIT) Roorkee. The study showed that natural underground contribution boosts the river's volume by nearly 120 per cent along the middle stretch. Meanwhile, more than 58 per cent of the river's water is lost to evaporation during summer -- an alarming yet overlooked component of the river's water budget. Published in the journal Hydrological Processes, the study reveals the negligible role of glacial melt in maintaining the Ganga's flow in the Indo-Gangetic plains during summer. The study quantifies that beyond the Himalayan foothills, the glacier-fed input is virtually absent and does not influence the summer discharge up to Patna. Post-Patna, tributaries like Ghaghara and Gandak become the dominant contributors. 'This research redefines how we can understand the Ganga's summer flow. It should prove a sustainable future river rejuvenation strategy, not just for the Ganga but for all major Indian rivers,' said Prof. K.K. Pant, Director of IIT Roorkee. Contrary to prior satellite-based studies warning of severe groundwater depletion across North India, the new findings based on a full-scale isotopic analysis of the Ganga River from its Himalayan origin to its deltaic end, including its major tributaries, indicate largely stable groundwater levels across the central Ganga Plain. In fact, consistent flows from shallow hand pumps across decades reinforce the evidence of a resilient aquifer system that continues to feed the Ganga during non-monsoon periods. 'Our analysis shows that the Ganga is not drying because groundwater is depleting, but due to over-extraction, excessive diversion, and neglect of tributaries. Groundwater is still the hidden lifeline of the Ganga,' said lead author Prof. Abhayanand Singh Maurya, faculty at the Department of Earth Sciences, IIT Roorkee. The findings strongly support reviving tributaries, increasing environmental flow releases from barrages, and protecting local water bodies to recharge aquifers.
