Every monsoon, as rivers swell and retreat, they breathe life into the land, carrying with them an invisible thread of sediment that has shaped the story of civilisation itself. Beneath the glimmering surface, grains of sand, silt, and clay travel downstream—slowly sculpting valleys, feeding deltas, and nurturing the soils that sustain us. Each river tells a story not just of water in motion but of earth on a journey. These drifting particles decide where forests grow, where villages take root, and where cultures rise and fade.
In the first part of the Sediment Stories series, Muddy Waters, we followed how sediments move through rivers, tracing their quiet yet powerful role in shaping landscapes. This chapter turns to the lives that have unfolded along their banks—the ways in which the movement of sediment has guided human settlement, survival, and belief.
For centuries, rivers have been the lifeblood of people. Yet, it is the sediment within them—the shifting foundation beneath our feet—that binds us to the rhythm of nature. What happens when that rhythm is interrupted, when the bond between people and the moving earth beneath the water begins to fade?
Archaeological evidence from many sites around the world in the form of pottery, bones, and stone tools shows that ancient communities chose to live in sediment-rich regions. In India too, excavations along the Indus and its tributaries reveal traces of early human life in fertile floodplains. These areas provided fertile soil, abundant water, and stable ecosystems, conditions made possible by the continuous movement and deposition of sediment.
At the heart of Karnataka, embraced by the Kaveri River, lies Srirangapatna, a living testament to how sediment and river flow shape civilisation. Formed by the Kaveri’s split into two branches that rejoin downstream, the island owes its existence to centuries of sediment deposition and erosion. Silt carried from the Western Ghats sculpted fertile land that nurtured one of South India’s great riverine kingdoms.
The land the Kaveri built became sacred ground, home to the 9th-century Ranganathaswamy Temple and Tipu Sultan’s Mysore. Its fertile soils, renewed by floods, sustained fields, groves, and livelihoods. Even today, its alluvial plains feed agriculture, while eroded banks reveal ancient artefacts, a reminder that Srirangapatna is a civilisation written in sand and silt.
This settling along rivers was influenced and really made possible by processes of sediment supply and transport that create and maintain complex ecosystems and habitats for freshwater organisms, replenish floodplains, deltas and coastlines, and impact critical fluxes in carbon and nutrients across watersheds. Sediments also regulate river flow, support the formation of wetlands and aquifers, and play a key role in maintaining water quality by filtering pollutants.
Even today, many communities continue to depend on river sediments for their livelihoods. In the farmlands of the Gangetic plains, people are farming in the floodplains, practising flood-recession agriculture, using the nutrient-rich alluvial soil left behind after seasonal floods. Communities continue to live and flourish along riverbanks, providing examples from across the country of human communities using river sediment in vernacular architecture, collecting molluscs and even using them as recreational or spiritual spaces.
Along the Sindh River in Madhya Pradesh, women use murram, a red, grainy sediment mixed with cow dung and water to strengthen and decorate their homes. In Goa, sandbanks along the Chapora River provide clams that locals collect for food and income.
Sediment also provides habitat for aquatic life, from fish to molluscs, supporting local diets and economies. The ability to adapt to shifting landscapes shaped by rivers and sediment has always been central to survival. People who live along rivers have learned to read the water’s moods and move with its flow.
The ability to manage and adapt to sediment-driven landscapes has thus been a cornerstone of settled agriculture and society. Communities understood that to live and benefit from the river and its sediments, one had to adapt to and live with the system’s changing, shifting nature. This relationship between humans and their rivers, mediated by the steady flow of sediment, was not only practical but also foundational to culture and survival.
“The constant interplay of land and water along the river, its constant deposition and erosion, and its seasonal flooding have shaped the riverine landscape over time and continue to intrinsically influence the myriad lives that inhabit the river ecosystem. When your life depends on the river, you learn its dance, predict its steps, and move with the changing seasons and flowing water.”Rhea Lopez | The River Will Not Be Mapped: Posterity #3
In some parts of India, this relationship with shifting sediment has been an important consideration in the governance of tidal rivers and floodplains. The Coastal Regulation Zone (CRZ) notification is one example of this, while Floodplain Zoning Laws enacted in a few states aim at preventing loss of life and property by restricting development in the floodplains. Land ownership and usage rights in shifting lands determined by sediment flows are often also codified. In the case of the Maharashtra Land Revenue code which includes a provision that allocates ‘temporary right to alluvial lands of small extent’ to govern ‘gaal per land’ (alluvial deposits) that are considered to belong to the river.
In the following sections we will be exploring two living examples from different parts of India that showcase a particular adaptation to living with shifting sediments. Assam’s chars and Goa’s khazans show how people continue to adapt to these dynamic landscapes.
For rivers like the Brahmaputra, which have a high sediment load, the varying sediment flux results in regular riverbank erosion, as well as sand island formations, locally called ‘chars’.
Over time, the chars stabilise and people inhabit them, but with an uncertainty of shifting island edges and erosion by floods. This uncertainty is not new; it is part of the lives of riverine communities, and they have learnt to navigate through it, as they understand the nature of the river. Consequently, the communities that settle on these ephemeral islands, called ‘choruas’, adapt to the uncertainty of the land and of displacement, developing local land-management systems that account for the regular erosion and exposure of islands.
Some monsoons bring with them layers of silt deposits that increase the char’s fertility for agriculture; other monsoons and floods take away parcels of land that were inhabited and food was grown on. Choruas relocate, resettle and rebuild their lives because of the shifting islands and riverbank edges. Their acknowledgement of the shifting landscape is a response that has, over years, helped them devise methods to grow, store and cook food, and transport and rebuild houses.
The use of the chars for settling, livelihoods or even the movement of humans and goods has to be managed and carried out with due consideration of the innate and unpredictable impermanence of sediment.
“Chars, as landscapes of flux, lie on the borderlines of land and water. They are a perfect example of an ecotonal space where the solid and the liquid existences of the land and water merge in myriad ways, resulting in the creation of unique lifestyles and livelihood choices, socio-economic identities and everyday narratives of survival.”Debdatta Chowdhury | Lands and Communities in Flux: The Chars in the Ganga-Brahmaputra Deltaic Region
Far from Assam’s silt islands, on Goa’s coast, lies another example of human ingenuity in negotiating with sediment. In the coastal state of Goa, an estimated 3-4,000 years ago, early communities had begun reclaiming marshlands in the floodplains of the state’s tidal rivers.
This system, known as the khazan system, controlled the influx of brackish, tidal water – enabling agriculture, creating opportunities for inland fisheries, and essentially making the land habitable.
The development of the khazans was founded on an understanding of the shapeshifting nature of the river and the movement of sediment. The construction and maintenance of bundhs depended on the influx of fresh sediment in the river, with bundh locations annually adjusted to the movement of the river.
Sediment plays an invaluable role in shaping human communities, not only through its contribution to fertile landscapes and healthy ecosystems but also by forming the very foundation of human settlements and cultural heritage. However, human interventions such as sand mining, the construction of dams, and the creation of concrete embankments and river channels significantly disrupt sediment flow and alter the sediment regimes of entire watersheds, leading to severe consequences for both natural environments and the human societies that have evolved from and depend on the natural flux of sediment. In our often misguided and unscientific efforts to control floods, we have restricted replenishment of floodplains with fertile soil and restricted the free flow of water (and sediment) within the watershed.
The removal or obstruction of sediment flows can result in coastal erosion, loss of fertile soils, and increased vulnerability to floods, directly threatening agricultural productivity and food security. Moreover, the depletion of sediment resources has far-reaching implications for infrastructure, as the weakening of natural barriers leaves human-made structures exposed to environmental stressors. Cultural landscapes, many of which are intimately linked to river systems and sediment-rich areas, are also at risk, as changing sediment dynamics alter the environments that have historically shaped local traditions and ways of life.
To safeguard human settlements, it is imperative that policies and practices evolve to recognise the essential functions of sediment and its shifting nature. Sustainable management practices must balance economic needs, such as sand extraction, with the preservation of sediment transport processes vital to ecological and social stability. Only through an integrated and conscientious approach can communities continue to thrive in harmony with their natural sediment landscapes.
This article is part of the ‘Sediment Stories’ series, highlighting the role of sediments in river ecosystems and communities. Veditum India Foundation and India Sand Watch track sand mining, advocate for sediment-inclusive policies, and share knowledge on this critical resource. Learn more at sandwatch.in