Landform Formation by Erosion

Water Cycle = Hydrological Cycle

• A series of events where water is stored and/or transferred.

Water Storage

                  

            

• Water is stored in lakes, rivers, clouds, snow, and glaciers.

Methods of Transfer• Precipitation (rain), rain runoff, condensation, sublimation,

evaporation, transpiration, and snowmelt.

                                                                         

• Weathering is the slow breakdown of rock through chemical, biological and physical processes

Weathering

Erosion• The breakdown of rock by wind,

gravity, water, and ice

Wind • AKA – Aeolian or alluvial Erosion• Causes sand dunes and alluvial fans

Gravity • Mass movement of sediment. • Ex. Landslides, mudslides,

avalanches

Water Erosion• Splash Erosion – caused by

raindrops• Sheet Erosion – caused by

flat sheets of rain pouring off

• Rill Erosion – caused by small narrow areas where rain gathers and drains.

• Gully Erosion – water then erodes away larger gullies.

Lateral Erosion• Erodes the sediments on

the sides of streams.• Meanders are the S

shaped bends in a river formed when a river flows over a flat plain.

• Rivers deposit sediment on the inside of curves and erode banks on the outside.

• The downward cutting into bedrock by a stream forming valleys (hilly) and gorges (mountainous).

Vertical Erosion

Oxbow Lakes• Sickle shaped lakes

that form from meanders.

• A meander is cutoff from the river leaving an oxbow lake.

River Delta

• River deltas are formed by constant deposition of sediment being deposited in the ocean or large lakes in a fan shape.

Shoreline Erosion• Caused by the

pounding of surf and tidal movements.

• Creates crescent shaped beaches.

Human Effects• Any process that

removes vegetation (ranching and some construction) increases erosion.

• Topsoil removal for farming also increases erosion.

Erosion in Alaska

• Matanuska River• Revegitation

and Erosion Control• Shishmaref Village (video)