A river delta is a landform, often triangular in shape, formed at the mouth of a river where it flows into a slower-moving or stagnant body of water such as an ocean, sea, lake, or reservoir. It is created by the deposition of sediments carried by the river as the flow velocity decreases upon entering the standing water, causing the sediments to settle and accumulate over time
. The delta typically consists of multiple smaller channels called distributaries, which spread out and deposit sediment across the delta plain. This process builds up the landform, which can take various shapes including the classic triangular form resembling the Greek letter delta (Δ), as well as other forms like bird-foot deltas
. River deltas are important ecological and human habitats, often serving as rich agricultural areas and population centers. They also act as natural coastal defenses and influence local water supplies. Geologically, they function as carbon sinks and evolve dynamically as sediment deposition and water flow patterns change over time
. In summary, a river delta is a sediment-rich, low-lying landform at a river's mouth, shaped by the interplay of river sediment supply, water flow reduction, and coastal processes