River

• A river basin is the portion of land drained by a river and its tributaries, encompassing all of the land surface dissected and drained by many streams and creeks that flow downhill into one another, and eventually into the main river.
• Malaysia Longest Rivers
• World Longest Rivers 56
• The River Long Profile 52 53 54@ZaharinAris
• The final destination of a river basin is an estuary which eventually carries it to lake.
• A river basin sends all the water falling on the surrounding land into the river, then to lake and eventually the estuary before the ocean.
• A river basin is closer than any other defined area of land, with the exception of an isolated island, to meeting the definition of an ecosystem in which all things, living and non-living, are connected and interdependent.
• A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river.
• A watershed is an area of land that catches rain and snow and drains or seeps into a marsh, stream, river, lake or groundwater.
• Both river basins and watersheds are areas of land that drain to a particular water body, such as a lake, stream, river or estuary.
• In a river basin, all the water drains to a large river.
• The term watershed is used to describe a smaller area of land that drains to a smaller stream, lake or wetland.
• There are many smaller watersheds within a river basin.
• A drainage basin is an area of land drained by a river and its tributaries.
• A watershed is the boundary between two drainage basins.
• A source is where a river starts.
• Rivers are responsible for most of the mass fluxes across the continents, carrying water, rock (as solid particles or in solution), and nutrients, and are vital for geology, ecology, and human society.
• When rain falls on the land, it either seeps into the ground or becomes runoff, which flows downhill into rivers and lakes, on its journey towards the seas.
• Percolation is the movement of water from the soil layer to the rock layer.
• Be aware of the factors that change the speed, and amount, of precipitation that reaches a river.
• A river forms from water moving from a higher elevation to a lower elevation, all due to gravity.
• A mouth is where a river ends (usually at the sea or a lake).
• A river is a system with inputs, stores, transfers, and outputs.
• P > ET leads to runoff, infiltration, groundwater flow, which are directed downslope by pressure gradients induced by gravity.
• Rivers are everywhere, even on other planets and moons, forming networks on Mars and Titan, and long, sinuous lava flows on the Moon, Venus.
• River regimes show how the discharge of a river varies over a longer period of time, usually a year.
• A flood or storm hydrograph shows how a river responds to one particular period of heavy rainfall, with a lag time being the time between the peak rainfall and the peak discharge of the river.
• Surface runoff is the water flowing directly overland to the river, sometimes called overland flow.
• Throughflow is the movement of water through the soil towards the river channel.
• Infiltration is the water passing through the earth surface in the drainage basin into the soil layer.
• A tributary is a smaller stream/river which flows into a larger one.
• If erosion rate depends on flux of water, land surface is unstable with respect to water erosion, leading to channelization.
• The positive feedback makes rivers cut valleys, and the rest of the landscape slopes toward them.
• The larger the spatial scale, the more dominant the positive feedback is, leading to river networks.
• The river picks up sediment and carries it downstream in different ways: traction, saltation, suspension, and solution.
• Thresholds: Finite strength of land surface and river banks due to cohesive sediment, ice, vegetation roots, etc.
• A confluence is the point where two rivers meet.
• The process of erosion can create different landforms, often found in the upper course of the river.
• The factors leading to deposition include shallow water, at the end of the river's journey, at the river's mouth, and when the volume of the water decreases.
• Smoothing by mass movement of soil/sediment, soil creep, small landslides, rain splash.