fluvial processes and landforms
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Fluvial Processes and Landforms on natural process courseTRANSCRIPT
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Fluvial Processes & LandformsLN 308 Natural Process: Fa LikitswatFaculty of Architecture and PlanningThammasat University10 July 2013
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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
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http://ngm.nationalgeographic.com/2010/04/water/water-animation
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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)
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The Hydrologic CycleWhy the ocean is not full?Endless water cycle =
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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.
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The Hydrologic Cycle
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Running Water // LandformsVolume of moving water is the single most important agent sculpturing Earth's land surface
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The term fluvial is applied to the processes and landforms associated with the action of running water
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Running Water Drainage BasinParticipationInfiltration
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Stream Flow
Gradient and Channel Characteristics
Discharge
Changes from Upstream to Downstream
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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.
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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.
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Source: The Federal Interagency Stream Restoration Working Group
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The Work of Running Water
Erosion
Transportation
Deposition
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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.
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Stream Erosion
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The cycle of Stream Erosion
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The cycle of Stream Erosion
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The cycle of Stream ErosionThe sequence of forms: 1) youth 2) maturity 3) old age
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Stream Transportation and Sediment
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Stream Transportation and Sediment
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solutionStream Transportation and Sediment
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Stream DepositionStreams and Point BarsFans
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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.
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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.
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Can you mark on this the fastest flow?What is a meander?
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where do you think erosion would take place?What is a meander
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Can you draw a cross section x-y?
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this is what a cross section through a meander looks like
What is a meander?
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Drainage PatternsThe form of a network of streams
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http://www.nasa.gov/pdf/703154main_earth_art-ebook.pdf
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Why do we need to understand about all of these? dynamicsmanagement
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Geologic time
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Water Fall
Canyon
Pothole
Floodplain
Oxbow lake
Alluvial Fan
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DiscussionFluvial Landforms