Erosion and deposition are processes that alter Earth’s surface. These occur when pieces of rocks and soil are carried away by flowing water, waves, winds, ice sheets or gravity and carried off to another part of Earth.
Erosion can wreak havoc with crops, alter coastlines and alter the entire landscape of a country, as well as cause air pollution. Climate is the primary factor behind erosion.
Weathering
Weathering, or the gradual breakdown of rocks under surface conditions, consists of their gradual dissolving or wearing away to form smaller and smaller fragments over time. This process may occur via physical processes (mechanical weathering) or chemical activities (chemical weathering).
Weathering occurs depending on factors like water, ice, acids, salts and the presence of plants and animals. Biologic weathering involves living things such as roots that penetrate cracks in rocks and plant growth that accelerate weathering processes.
Chemical weathering occurs when chemical changes to rock are hastened by external environmental influences like rainfall and temperature; water and warmer temperatures increase its rate. Oxygen attacks minerals to form alteration products which dissolve or transform them over time.
Weathering causes deposits of altered and loose material to be exposed to wind, running water, waves and glaciers for transport across Earth’s surface and eventually away from their source area. Erosion then carries this material, often transporting fragments of rock from its original location with it.
Runoff
Rain does not just fall on land; rather, some of it runs off as runoff and affects the landscape in various ways, including erosion and deposition.
Erosion and deposition can impact everything from topsoil, vegetation, wildlife habitat and runoff into streams or rivers causing water pollution.
Human activities can increase erosion by altering ecosystems and habitats, for instance by cutting trees down, plowing fields, or overgrazing livestock – actions which disrupt roots that help hold soil together, as well as alter ecosystems and habitats.
Climate change is altering precipitation patterns and can increase erosion. Because more rain than snow falls as raindrops, melting takes place faster.
Groundwater
Groundwater is defined as any body of water found underground that accumulates between rock particles or in fractures in rocks, providing us with drinking and bathing water, or being used for daily tasks like dish-washing and clothing cleaning.
Once water reaches these saturated zones, it seeps downward through an area aerated with both air and moisture – this area is known as the water table.
As rainwater and snowmelt evaporates onto the earth’s surface, they collect in saturated zones until eventually being deposited in dense rock called an aquifer.
Aquifers store water underground for long periods, providing access to surface supplies in times of drought. In addition, aquifers may also help recharge surface supplies when necessary.
People relying on groundwater for drinking, agriculture and industry can rely on it for safe supplies of drinking water and industrial applications; however, groundwater sources are vulnerable to pollution from sources like fracking chemicals, leaky landfills or septic tanks as well as other point and nonpoint sources of pollution.
Ocean waves
Ocean waves are powerful forces at work along the coastline that can alter landforms. For instance, they may erode cliffs or deposit sand on beaches.
Erosion also plays an integral part in shaping distinct landforms such as sea-arches, sea stacks and wave-cut cliffs. Erosion occurs when water penetrates cracks in rocks near the shoreline, forcing air into them and breaking off pieces of rock formation from within them.
Sediments carried by rivers, runoff and streams act like sandpaper to erode shorelines. The larger and heavier waves are, and more sediment they carry with them, the more erosion they cause.
Waves can erode rocky shorelines through hydraulic action, attrition and abrasion. Hydraulic action uses water pressure to force air through cracks in cliffs to break off pieces of rock; attrition separates out soluble rocks while abrasion grinds and smashes the surface, smoothing it while breaking off bits off as it goes along; these three forms of erosion all work in concert to erode rock edges away from shorelines.