Erosion by water
Water moving downhill can carry away pieces of rock and soil
Temperature changes cause pieces of rock to flake away from the surface. Also, the acid in rainwater dissolves rocks containing calcium carbonate. These processes are called weathering.
Water erosion happens when water moves the pieces of rock or soil downhill. Waves also carry away small pieces of material. A wave can wash up onto the surface of rock or soil and then carry away pieces of material as it flows back into the ocean or lake.
The size of earth materials that can be moved by water depends on how fast the water is moving. A fast-flowing stream can carry large rocks while a slow-moving stream might only be able to carry very small things like clay. Canyons are among the most obvious features made by erosion. Where a river meets the sea, it drops the solids, sometimes making a river delta.
Drainage basin of the Amazon
Aletsch Glacier is the biggest glacier in the Alps
Large tropical rivers like the Paraná, Indus, Brahmaputra, Ganges, Zambezi, Mississippi and the Amazon carry huge amounts of sediment down to the sea. The Nile, perhaps the world's longest river, carries much less sediment than the others because, part of the way, it runs through less fertile regions than the other great rivers.
The Amazon has by far the largest waterflow, with an average discharge greater than the next seven largest rivers combined. It has the largest drainage basin in the world, about 7,050,000 square kilometres (2,720,000 sq mi). The Amazon accounts for about one-fifth of the world's total river flow.
The sediment discharged by the gigantic mouth of the Amazon stains the sea brown for hundreds of miles out to sea.
When a glacier moves downhill,it pushes & pulls rocks with it. There is also another way. Cold weather causes water inside tiny cracks in rocks to freeze. When it freezes, the ice gets larger,& pushes hard against the rock to break it.