Erosion
 Rocks breaking down into smaller pieces
Runoff
 Water that moves over Earth’s surface
 Causes sheet erosion
 Moves downhill
 Forms rills, gullies, streams, rivers, tributaries
 When runoff flows in a thin layer it may cause sheet erosion
 Amount of runoff depends on amount of rain, vegetation in area, type of soil, land
shape, and how people use the land
 Increases due to pavement, like parking lots because water cannot be absorbed into
asphalt
 Increases due to farming because vegetation (trees, shrubs) is cut down
 Rills- tiny grooves in the soil
 Gully- large groove or channel in the soil that carries runoff
 Tributary-stream or river that flows into a larger river
Rivers
 Erosion creates valleys, waterfalls, flood plains, meanders, oxbow lakes
 Deposition creates alluvial fans, deltas, add soil to flood plain
 Waterfalls wear down softer rock
 Flood plain- flat, wide area of land around river, covered by water when river floods, in
places like Egypt flood plains provide fertile soil for growing crops along big rivers like
the Nile
 Meander-looplike bend in a river, becomes more and more curved over time
 Oxbow lake- meander that has been cut off from river, can form during flooding
 alluvial fans- wide sloping deposit of sediment where a stream leaves a mountain range
 deltas- sediment deposited when a river enters the ocean, example- Mississippi River
creates a delta when it enters the Gulf of Mexico in New Orleans
Groundwater
 Underground water
 Chemical weathering-water sinks into the ground and combines with CO2 to form
carbonic acid in a chemical reaction, breaks down limestone
 Forms caves, stalactite (roof) and stalagmite (floor)

Glaciers
 Continental glaciers-covers much of continent, island, like Greenland and Antarctica, ice
age is when continental glaciers cover most of the Earth
 Valley glaciers-long, narrow glacier from snow and ice in mountain valley, usually move
down valleys that have been cut by rivers
 Glaciers form when more snow falls than melts, snow and ice builds up
 Plucking-picks up rocks as the glacier flows, can crush rocks, can move big boulders
 Breaks rocks
 Drags rocks which scratches bedrock, called abrasion
 Deposits sediment when it melts- till, moraine, kettle
 till- sediments and particles left by a glacier when it melts
 Moraine- till deposited at edge of glacier, forms ridge, Long Island is a moraine
 KettleWaves
 Energy comes from wind blown across water’s surface
 Break apart rocks on shore
 Abrasion-headland, arch, cave
 Deposit sediment-beaches, spits, sandbars, barrier beaches
Wind
 Deflation-wind removes surface materials, Dust Bowl
 Abrasion-Polishes rock, little erosion
 Deposits-sand dunes, loess-sediment that is finer than sand