How does water weather rocks and reshape landscapes?

Water reshapes landscapes and weathers rocks through a combination of physical, chemical, and mechanical processes.

Weathering Processes

Water contributes to the disintegration and decay of rock through several mechanisms:
* Physical Weathering: The alternate freezing and thawing of water within rock cracks and fissures exerts mechanical force, causing the rock to break apart.1
* Chemical Weathering: Circulating water facilitates processes such as solution, carbonation, hydration, and oxidation, which alter or redistribute the mineral composition of rocks.1
* Glacial Action: Temperate glaciers use water-derived processes to erode their beds. Basal sliding, enabled by meltwater, allows glaciers to act like sandpaper, using trapped rock debris to abrade and carve the landscape. Glaciers also perform "plucking," where hydraulic pressure and the refreezing of water (regelation) help remove large pieces of bedrock.2

Landscape Evolution

Rivers are primary agents in sculpting the Earth's surface. They create the valleys and canyons through which they flow by expending energy in vertical entrenchment and lateral erosion. Over time, rivers work toward a graded condition, balancing the resistance of rocks with erosional processes. As rivers approach base level, they shift from deep, narrow downcutting to lateral widening, gradually transforming the morphology of valleys and plains.345