In a scientific advancement, researchers have come up with a new tool named ‘sediment budget or sedimentation bank’ for analysing the changing riverbeds in India. It is being described as a first-of-its-kind sedimentation budget for Indian rivers, designed to systematically map sediment movement at the river-basin scale. The main objective of the tool is to trace the riverbeds and regulate them, as these are gradually transforming the future of Indian rivers. In the wake of the River Ganga having the worst drought since the 16th century CE, the tool can facilitate the river revival efforts of the Indian government. It is used to chart the movement of sediment in the rivers of India and offers planners a clearer way to track and manage the shifting riverbeds reshaping India’s water future.
The scientific framework behind this tool has been elaborated in a study published in Environmental Research Letters on June 27, 2025, titled ‘Unravelling sediment sources and sinks in the large Ganga River System’. It is authored by Vikrant Jain et.al.
Defining Sediment Budget
As a pioneering tool, the Sediment Budget records the inflow, outflow, and changes in the storage of sediment in a river basin, lake, coastal area, or a reservoir over a particular period of time. In other words, it is a systematic evaluation of the amount of fluctuations in the sediment within a defined geographic area and time frame. It works like an accounting-style system that maps where riverbed sediments originate and where they accumulate.
Need for Sediment Budget Tool
In today’s times, soil erosion, alteration in the course of rivers, and collapse of river banks are on the rise due to unexpected climate change and random development. Owing to sediment imbalance, flood risks have been increased; river morphology has been changed; and farmlands have been destroyed. In order to deal with these issues effectively, the Sediment Budget Tool should be used. According to the researchers, the same model can be employed to frame customised rejuvenation strategies across the country.
Importance of Sediment Budget Tool
The Sediment Budget Tool plays an important role in comprehending the patterns of sediment transportation and deposition in various systems. The sources, transport mechanisms, and sinks of sediment can be evaluated with the help of the inclusive framework provided by the tool. This is a pre-requirement to tackle hazards associated with sediment and to form restoration and preservation strategies that are efficient and practicable.
Apart from gaining insight into the sediment dynamics, the Sediment Budget enables the identification of regions having high level of sediment yield and the projection of the implications of human activities and natural phenomena like climate change on transportation and deposition of sediment. For the Ganga basin, the integrated Sediment Budget reveals, for example, that:
- The Eastern Himalayan Hinterland, though it covers only about 11 per cent of the basin area, generates nearly 51 per cent of the total sedimentation load.
- The Transitional Himalayan Hinterland contributes about 23 per cent of the sediment load from roughly 9 per cent of the basin area.
- The Western Ganga rivers, despite draining around 27 per cent of the basin area, contribute only about 9 per cent of the total sediment load, indicating a relatively supply-limited system.
Besides, it can facilitate decision-making while managing sediment-induced hazards, including sedimentation, erosion, flooding, etc. A proper knowledge of the Sediment Budget enables managers to form strategies based on targets, which in turn minimises the risk of these hazards, thereby safeguarding ecosystems, agricultural lands, and infrastructure.
Background
Several scientists and researchers have considerably contributed to the development and evolution of the Sediment Budget over the course of time. In the beginning, the main purpose of the Sediment Budget was to gain knowledge about the transport processes of sediment in rivers and coastal regions. Later, as the Sediment Budget Model came into existence, more advancement took place in this field, as sediment fluctuations can now be evaluated via a quantitative framework.
Use of Sediment Budget in River Revival Efforts of India
Sediment Budget is capable of strengthening the efforts of Indian government in the restoration of its rivers. It traces the movement of sediment via waterways.
It has been created by the researchers working at IIT Gandhinagar and the Prayoga Institute of Education Research with collaboration from the University of Delhi. Similar to an accounting system, the tool records the origin of the riverbed sediments and the places of their accumulation. This enables the planners to get a better understanding of managing and reviving the fragile river systems.
The basin-scale Sediment Budget for the Ganga estimates that about 385 million tonnes (Mt) of sediment are generated annually in the basin. Of this, nearly 52 per cent (around 199
Mta-1) currently reaches the basin outlet at Farakka, while the remaining is stored within the basin in different sinks.
There were extreme climatic shocks everywhere in India when the tool came into being in 2025. For instance, Uttarakhand suffered devastating landslides and Himachal Pradesh faced severe flash floods. Besides, the largest river in India, the Ganga, is drying at a rapid rate. According to the scientists, this has not been witnessed since the 16th century. It is to be noted that the river is responsible for sustaining about 600 million people and is known to account for about 40 per cent of total gross domestic product of India. The decline in the water level of the Ganga has been aggravated by the continuous retreating of glaciers in the Himalayas.
In response to these issues, the Government of India has taken the usual mitigation steps, which include planting more trees, controlling pollution, banning diversion of water and extraction of groundwater, along with implementing urban planning reforms. However, in the opinion of researchers, sedimentation, which is one of the most basic aspects of the rivers, has been ignored for long.
Role of Sedimentation
The role of sedimentation is described below:
- With sedimentation, the alteration in the river flow pattern due to climate change can be assessed. When there is excessive rainfall, sediments erode considerably and travel to long distances, thereby causing floods in the river banks. As a result, some places get water logged, while others get filled with saltwater. This reduces the soil fertility of agricultural lands. On the contrary, when there is less rainfall, little erosion of sediments takes place, but they scatter to nearby places and strip them off.
- Sometimes, there is loss of sediment due to climate change. This leads to weakening of banks, and eventually they get collapsed. With human activities in the region, the issue gets worsened. These activities include river rerouting, reckless construction, clearing of trees and plants, intrusion on riparian land and unregulated development. They aggravate the soil erosion. This harsh reality came into focus in Murshidabad district, where part of the Ganga-Bhagirathi river bank collapsed, which affected the communities by displacing them. Besides, their farms also got destroyed.
- The river’s natural flow also gets imbalanced due to sand mining, dams, and dredging, though these are used to control flood and facilitate navigation. All these change the speed of the flowing river water, and thus, pose greater risks of downstream flood.
- The fertility of the land gets affected by imbalance in the distribution of sediment. Owing to their light-weight, finer sediments flow down further towards the downstream and get deposited there. Consequently, there is lack of nutrients in the farmlands near upstream. Bigger chunks of sediments get deposited behind the dams. Owing to the varied amount of sediment deposition in the course of a river over time, it is likely that the river may divide into several channels, or change its route, or may even get completely dried out.
At this point, the Sedimentation Budget Tool comes handy. As the tool traces the sources of sediment and their destinations, it records the movement and accumulation of the sediment in a ledger, which is similar to a budget. This acts as a guideline for policymakers, who can then predict hazards, frame procedures for restoration of the rivers, and review whether the measures taken by them are effective or not. It also helps policymakers during river and watershed planning, particularly related to the implications of large infrastructure projects, by improving their ability to anticipate sediment-driven risks.
Conclusion
The Sedimentation Budget is an important tool that may highlight that the erosion from agricultural lands constitutes most of the sediment load. With this knowledge, the targeted strategies for conservation can be designed, which not only reduce erosion but also minimise hazards caused by sediment.
The tool gives us valuable insight into the direction and amount of the sediment that is being moved in a particular region over a specific period of time. The tool also reveals the impacts of the aforesaid sediment dynamics over river ecosystem and on its management. As highlighted by the researchers, the Sedimentation Budget offers a replicable template that can be applied across different river systems to support targeted rejuvenation and ecosystem-based river management.
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