three ways in which a river erodes its channel.?
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There is headward erision (where the upper course erodes at the head), Gulley Erosion( where it forms gorges and gulleys) and there is erosion by debris(bigger rocks or stones along the river bed). These can also cause potholes in the river bed.
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Water\n\nSplash erosion is the detachment and airborne movement of small soil particles caused by the impact of raindrops on soil. Sheet erosion is the result of heavy rain on bare soil where water flows as a sheet down any gradient, carrying soil particles. Where precipitation rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence can often cause more erosion than the initial raindrop impact. Gully erosion results where water flows along a linear depression eroding a trench or gully.\n\nValley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and headward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached the erosive activity switches to lateral erosion which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes, suspended abrasive particles, pebbles and boulders can also act erosively, as they traverse a surface.\n\nWind\n\nWind erosion, also known as eolian erosion is the movement of rock and/or sediment by the wind. Windbreaks are often planted by farmers to reduce wind erosion. This includes the planting of trees, shrubs, or other vegetation, usually perpendicular or nearly so to the principal wind direction. The wind causes dust particles to be lifted and therefore moved to another region. Wind erosion generally occurs in areas with little or no vegetation, often in areas where there is insufficient rainfall to support vegetation. An example is the formation of sand dunes, on a beach or in a desert.\n\nGlacial\n\nIce erosion is caused by movement of ice, typically as glaciers. Glaciers can scrape down a slope and break up rock and then transport it, leaving moraines, drumlins and glacial erratics in their wake, typically at the terminus or during glacier retreat. Ice wedging is the weathering process in which water trapped in tiny rock cracks freezes and expands, breaking the rock. This can lead to gravity erosion on steep slopes. The scree which forms at the bottom of a steep mountainside is mostly formed from pieces of rock broken away by this means. It is a common engineering problem, wherever rock cliffs are alongside roads, because morning thaws can drop hazardous rock pieces onto the road.
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What happens in a massive river flood is that sedimanet is moved around.  So it's possible that the swollen riven carves early in it's journey and redeposits the silt farther downstream.  Not strange at all.\n\nOn the Rio Grande, it's documented that during one particularly strange day, a side river flooded into the Rio Grande causing it to flow backwards for nearly an hour.  Geology is not the slow, plodding horse teachers might lead you to believe, rather, it happens in spurts, earthquakes, floods, etc.  The everyday action just smooths the edges.
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weathering of rocks due to wind,flowing water
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Remember the three r's\n\nRoads Rails Rivers
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1) iceberg\n2) nothing\n3) shadow\n4) a sponge!\n5) river
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Water...\n\n* Liquid water, eg in rivers and coasts (in the sea this is largely caused by the gravitational effect of the moon);\n* Liquid water is a major cause of landslides - soil becomes over-saturated and therefore loses its adhesion to the soil or rock beneath;\n* The action of freeze-thaw where liquid water seeps into cracks, expands when it freezes thereby widening the crack and ultimately splitting rocks apart;\n* Frozen water in the form of glaciers grinding away at mountains;\n\nOther causes of erosion include:-\n* the wind, especially when it blows sand particles with it which erode rocks;\n* the Sun which alternatively heats and cools rocks so that they split in much they same way as freeze-thaw (especially in desert areas);\n* humans - we contribute to many of the above processes by our own actions, eg deforestation prevents the soil from holding as much water so landslides become more likely; over-farming creates deserts which are subject to wind and sun; coastal "management" often results in more rapid erosion of some areas of coastline
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A - A meander is a bendy bit of a river.\n\nC - A strange example though. A & B are physical/mechanical weathering and D is through the action of flora/forna. I'm not sure C actually happens often but it is the only chemical action.\n\nB - Limestone will dissolve in a weak acid. Another formation it produces are limestone pavements.\n\nHope this helps
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boats.\n\n\nAnd water.  Lots of water.
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The rivers are cresting and there is a lot of standing ground water that will slowly be absorbed or drain off.
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Dams and levees change the course of rivers.  Farmig, forestry, and suburban development lead to erosion.  Mining can change the forms of mountains.
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The mouth of the river meets a larger body of water.  A delta forms from sediment deposited at the mouth of the river.  Some coastal rivers flow into estuaries, where fresh and salt water mix.
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They don't hold water that is why they are called rivers - the water flows out.
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It's called a river delta. For example, the Mississippi Delta, the Nile Delta, etc. You could also be referring to a river channel mouth bar, which is only a small part of a delta found where the water speed slows from the opening up of the channel into the open ocean, thus causing the water to drop its sediment load.
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Wind: Creates dunes and erodes rock\nRain: Erode the land and forms the river and lakes\nGlaciers: Formation of the glaciers is due to atmospheric effects, so is their melting, which as they slide down mountains craves things up.
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Geographically speaking, a river which is said to be rejuvenated when the base level that it is flowing down to, is lowered. This can happen by uplift of land, or by a sea or lake that it is flowing into becoming lower. That makes the river suddenly start eroding its bed down faster as it gains in gravitational potential energy. That causes effects such as meanders cut down as gorges, steps where the river suddenly starts flowing faster, and terraces derived from old flood plains.\n\nOne example is the Nile, which was rejuvenated when the Mediterranean Sea dried up in the late Miocene. Its base level dropped from sea level to over 2 miles below sea level. It cut its bed down to several hundred feet below sea level at Aswan and 8000 feet below sea level at Cairo. After the Mediterranean re-flooded, those gorges gradually filled with silt.
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D. spillting of water\n\n100%