Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity...
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Transcript of Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity...
![Page 2: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/2.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
![Page 3: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/3.jpg)
![Page 4: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/4.jpg)
![Page 5: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/5.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Discharge
• The volume of water that passes through a cross-section per unit of time.
• Cubic metres per second.
• Increases due to the input from a greater amount of the river basin above that point.
![Page 6: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/6.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Occupied Channel Width
• Distance across the actual channel, measured at the water surface.
• Increases due to increase in discharge, input from tributaries etc.
![Page 7: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/7.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Channel Depth
• The height from the water surface to the stream bed.
• Increase downstream as does the size of the river.
• Line connecting places of greatest depth is called the thalweg.
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![Page 9: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/9.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Average Velocity
• Is the speed of water flow (distance travelled per unit of time).
• Steady increase downstream.
• How can it be so if the gradient is deceasing? (imagine 2 slides – one steep, one less so).
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• Downstream the river becomes more efficient with proportionally less contact with its bed and banks.
• Shown by higher Hydraulic Radius and lower Channel Bed Roughness.
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![Page 12: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/12.jpg)
Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Load Quantity
• Capacity of the river.
• Total load of all sizes.
• Increases with discharge and velocity.
![Page 13: Bradshaw Model. Upstream Downstream Discharge Occupied channel width Channel depth Average velocity Load quantity Load particle size Channel bed roughness.](https://reader036.fdocuments.net/reader036/viewer/2022081421/5697c00d1a28abf838cc9912/html5/thumbnails/13.jpg)
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Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Load Particle Size
• Decreases considerably downstream.
• Angular pebbles become more rounded.
• Attrition.
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Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Channel Bed Roughness
• Decreases because of fewer stones etc, small load particle size etc.
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Upstream Downstream
Discharge
Occupied channel width
Channel depth
Average velocity
Load quantity
Load particle size
Channel bed roughness
Slope angle (gradient)
Slope Angle
• Decreases.
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