Presentation on theme: "Fluvial Morphology: Landforms Made by Running Water"— Presentation transcript:
1 Fluvial Morphology: Landforms Made by Running Water
2 RUNNING WATER Rivers and Streams What is the most important geomorphic agent shaping the landscape?RUNNING WATER Rivers and StreamsWhat is the work of rivers and streams?ErosionTransportationDepositionFluvial Morphology: Study of Landforms Made by Running WaterFLUVIAL: from the Latin fluvins for ‘running water’ or streamflow2
4 The Long Profile of Streams At their headwaters, the grade of a stream is usually steep.At Mid-streams, the angle of the grade becomes more gently sloping.Near the mouth of the stream, the grade becomes almost flat.
9 The Cycle of Erosion Youthful stage headward erosion and vertical downcutting dominantsteep stream gradients promote valley deepeningnarrow, V-shaped valleys9
10 The channel at upstream point A-B This channel is located in the stream's headwaters.The stream gradient and surrounding topography is quite steep.Stream velocity is at a maximum and cuts a narrow deep channel.The floodplain is minimal as high velocities carry all sizes of load down stream.Stream load is high as the steep gradient provides the energy for extensive erosionProducing a V-shaped river valley.
14 Waterfalls and RapidsHard rock layers have not yet been smoothed awayA waterfall is a vertical drop in a streambedRapids are stream sections with extremely strong currents.Both are sites of vigorous erosionPotential Hydro Electric Power
18 Figure c-d: Stream channel near the middle of a typical stream profile.
19 Causes a sudden reduction in the stream's velocity. The channel is now leaving the mountainous terrain and entering a landscape that is more gently sloping.Causes a sudden reduction in the stream's velocity.The stream adjusts to this change, by depositing most of its coarse stream load onto the floodplain.The stream also takes on a braided channel form.These channels are always changing in size, number, and location
20 Lateral Erosion - Valley Widening Begins Erosion is greatest on the outside bendCut-banksDeposition on the inside bendMeandersWiden the valleyForm cutoffsCreate oxbow lakes
24 Stream Stage 3 - Old AgeCharacteristics of Old Age StreamsWide Alluvial Valley StageNatural LeveesDepositional featureParallel to the stream channel on both banks
25 The channel near the mouth of the stream (Figure E-F). Extensive flat floodplain is composed of Deposits from channel meandering.The channel is quite large and U-shaped.Stream discharge is at a maximum and sediment load is generally composed of finer materials.
32 . Some deltas, like the Nile, have a triangular shape Fig a, p. 49132
33 Ganges River Delta Image taken 2/28/2000 The Ganges River forms an extensive delta where it empties into the Bay of Bengal. The delta is largely covered with a swamp forest known as the Sunderbans, which is home to the Royal Bengal Tiger.The Ganges River Delta can be found on Landsat 7 WRS Path 137 Row 44, center: 23.12,