UNIT 4: AGENTS OF EROSION

UNIT BIG IDEA/ESSENTIAL QUESTIONS Water and wind are active agents of erosion

that constantly reshapes the earth’s surface. Essential Questions

How does porosity, permeability, aquitards, and aquifers influence groundwater?

What conditions would create karst topography? What importance does deltas have? How can glaciation erode, alter, and reshape the

earth’s surface?

ES Standards: 3.1, 3.4, 3.5

KEY VOCABULARY Alluvial fan Delta Drainage basin Infiltration Karst topography Meander Natural levee Oxbow lake Permeability Porosity

Alpine glacier Arete Cirque Deflation Drumlin Moraine (lateral,

medial) Till Zone of accumulation Zone of wastage

RECAPWeathering-process that breaks

downs materials (chemical and/or mechanically) at the earth’s surface.

Erosion- removes weathered material by wind and water.

Deposition- deposits eroded material in a new location making new features

QUESTION OF THE DAY

What is the hydrological cycle?

WATER Infiltration depends on

Intensity/duration of rainfallPrior wetted condition of soilSoil textureSlope of the landNature of vegetative cover

What is a Drainage Basin? River Systems

3 parts: zone of erosion, zone of sediment transport, zone of sediment deposition

STREAMFLOW Laminar or Turbulent

Which type of flow is responsible for whitewater rapids?

Stream Velocity is based uponGradientShape, size, and roughness of

channelDischarge

Width x depth x velocity

TRANSPORTATION OF ERODED MATERIAL Dissolved load, Suspended Load, Bed Load

Competence determines the maximum size of particles that can be carried

Capacity is based upon a streams discharge

Stream ChannelsBedrockAlluvial

Meanders, Oxbow Lakes, Cut banks and Point bars

Stream Valleys

DEPOSITIONAL FEATURES Floodplains Delta Levees Alluvial Fans

QUESTION OF THE DAYWhat are some ways to control flooding?

GROUNDWATERRate of movement and amount

depends onPorosityPermeabilityAquitardsAquifers

GLACIATION Two types Glacial Movement

Zone of accumulation Zone of wastage

Erosion by plucking and abrasion

GLACIAL FEATURES VIA EROSION Glacial Trough Hanging Valleys Cirques Aretes Horns Fjords

DEPOSITIONAL FEATURES Till vs. Stratified Drift Glacial Erratics Moranines Outwash Plains Drumlins Eskers Kames Kettle Lakes

CAUSES OF GLACIATION Plate Tectonics Changes in Earth’s Orbit Changes in output energy from Sun Albedo and Atmosphere composition

WIND EROSION AND DEPOSITION Deflations and Abrasion Loess Sand Dunes