Fluvial Processes & LandformsLN 308 Natural Process: Fa LikitswatFaculty of Architecture and PlanningThammasat University10 July 2013

Earth as a System : The Hydrologic CycleRunning Water Stream FlowGradient and Channel CharacteristicsDischargeChanges from Upstream to Downstream

The Work of Running WaterErosionTransportationDeposition

Stream ErosionStream Transportation and SedimentStream DepositionStreams and Point BarsFansFluvial landforms

http://ngm.nationalgeographic.com/2010/04/water/water-animation

http://blog.art21.org/2013/05/03/exclusive-maya-lin-reflects-on-new-yorks-ecology-and-the-effects-of-hurricane-sandy/Maya Lin : Pin River-Hudson (2009)

The Hydrologic CycleWhy the ocean is not full?Endless water cycle =

The Hydrologic Cycle

The continuous interchange of water among the ocean, atmosphere, and continents

The processes involved in the hydrologic cycle include precipitation, evaporation, infiltration, runoff, and transpiration.

The Hydrologic Cycle

Running Water // LandformsVolume of moving water is the single most important agent sculpturing Earth's land surface

The term fluvial is applied to the processes and landforms associated with the action of running water

Running Water Drainage BasinParticipationInfiltration

Stream Flow

Gradient and Channel Characteristics

Discharge

Changes from Upstream to Downstream

Stream FlowThe factors that determine a stream's velocity

Gradient = slope of the stream channel

Shape

Size

Roughness

Discharge

Most often, the gradient and roughness of a stream decrease downstream, while width, depth, discharge, and velocity increase.

Stream ChannelsStream channels are two basic types: bedrock channels and alluvial channels.

Bedrock channels are most common in headwaters regions where the gradients are steep. Rapids and waterfalls are common features.

Two types of alluvial channels are meandering channels and braided channels.

Source: The Federal Interagency Stream Restoration Working Group

The Work of Running Water

Erosion

Transportation

Deposition

A river process is something that happens in the river. The main processes in the river are

Erosion - where parts of the river bed and bank get eroded / removed from the landscape Transportation - where the eroded material is carried from one place to another through the river system Deposition - where the river load becomes too heavy for the river to carry and is dumped down / deposited.

Stream Erosion

The cycle of Stream Erosion

The cycle of Stream Erosion

The cycle of Stream ErosionThe sequence of forms: 1) youth 2) maturity 3) old age

Stream Transportation and Sediment

Stream Transportation and Sediment

solutionStream Transportation and Sediment

Stream DepositionStreams and Point BarsFans

Stream DepositionStreams deposit sediments when velocity slows and competence is reduced. This results in sorting, the process by which like-sized particles are deposited together. Stream deposits are called alluvium and may occurs as channel deposits calls bars, as floodplain deposits, which include natural levees, and as deltas or alluvial fans at the mouths of streams.

Cross-sectional profiles of riffle and pools within a meandering river. Note the asymmetric profile ofpools located in meander bends and symmetrical profiles of riffle sections within straight channel reaches.

Can you mark on this the fastest flow?What is a meander?

where do you think erosion would take place?What is a meander

Can you draw a cross section x-y?

this is what a cross section through a meander looks like

What is a meander?

Drainage PatternsThe form of a network of streams

http://www.nasa.gov/pdf/703154main_earth_art-ebook.pdf

Why do we need to understand about all of these? dynamicsmanagement

Geologic time

Water Fall

Canyon

Pothole

Floodplain

Oxbow lake

Alluvial Fan

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DiscussionFluvial Landforms