A drainage basin is the area drained by a river and its tributaries. A watershed or drainage divide separates adjacent basins in the relevant geographical usage.

A tributary joins another river; a distributary branches away, commonly in a deltaic setting. These terms describe relationships, not river size alone.

Drainage pattern depends on slope, rock structure and geological history rather than arbitrary political boundaries.

Himalayan rivers receive water from varied sources including rainfall and snow or ice melt, with proportions differing by basin and season.

Many peninsular rivers have strong seasonal rainfall dependence and flow over older terrain, but broad labels have exceptions.

Deltas form through sediment deposition under favourable conditions; estuaries involve distinctive river-sea interaction and are not the same landform.

Erosion, transportation and deposition occur along a river in changing proportions according to flow, sediment and channel conditions.

Floodplains are created through river processes and can be fertile while also exposed to inundation and channel change.

A basin approach is useful because upstream land use and water management influence downstream conditions across administrative borders.

A drainage basin is the area contributing water to a river system; a drainage divide separates neighbouring basins. A tributary joins a main channel, while a distributary branches from it in the relevant setting, often near a delta. The largest-looking stream on a local sketch does not necessarily determine the hydrological hierarchy; follow the basin and confluence relationships.

Dendritic drainage resembles a branching tree and often develops where underlying conditions do not impose strong directional control. Trellis and rectangular patterns can reflect structural influences, while radial drainage flows outward from a central highland. A pattern is evidence about relief and structure, not a substitute for examining the local geology.

Himalayan rivers commonly combine snow or glacier contributions with rainfall and seasonal basin storage, while many peninsular systems depend more strongly on monsoon rainfall. These are broad contrasts, not rules that every Himalayan reach flows steadily all year or every peninsular river becomes dry. Dams, groundwater, basin size, and regional rainfall modify seasonal behaviour.

A river’s work depends on discharge, gradient, sediment supply, and the materials through which it flows. Flooding occurs when water leaves the usual channel, but flood hazard is not determined by rainfall alone. Upstream land use, channel capacity, embankments, sedimentation, floodplain occupation, and drainage congestion affect exposure and consequences.

Meanders involve erosion and deposition in different parts of a bend. Cut-offs can create oxbow lakes, while channel migration can shift the location of erosion hazards over time. A floodplain is part of a functioning river system, not simply vacant land beside a permanently fixed line on a map. Human settlement and infrastructure can increase the damage caused by a similar hydrological event.

Deltas develop where river-borne sediment accumulates under suitable coastal conditions; estuaries involve different tidal and coastal interactions. Not every river mouth produces the same landform. Compare the Ganga–Brahmaputra delta with western peninsular estuarine examples through sediment supply, basin and coast characteristics, and marine influence. In a resource-management answer, connect upstream and downstream interests rather than treating a river as isolated sections inside administrative borders.