Study of Stream Channel

The variations of channel geometry

Group 4

Discussion Topic

1. Summarize and describe the main findings the variations of channel geometry.

Upper course

Middle course

Lower course

River

(Area A1&2) (Area B3&4) (Area C5&6)

Channel geometrye.g. the width, depth, length, gradient and wetted perimeter

Upper course

Middle course

Lower course

Area B4

Area C5

Area A2

Compare of the channel Geometry

Area A2 Area B4 Area C5Average depth(cm)

17.1 13.347 12.45

Width(cm) 386 760 2060Wetted perimeter(m)

8.2 7.6 20.6

Average gradient

4 degrees 45 min

0 degrees 50 min

3 degrees 10 min

Upper Course (Area A2)

Middle course

Area B4

Lower course (Area C5)

Upper course Width: less lateral erosion narrow Depth: serious vertical erosion deep Length: straight river course short Gradient: serious erosion steep slope Wetted perimeter: narrow

Factors affecting geometry

Middle course Width: more lateral erosion than upper cours

e Depth: less vertical erosion than the upper co

urse Length: meanders exist longer than upper course Gradient: less erosion less steep slope Wetted perimeter: wide

Lower course Width: serious lateral erosion wide Depth: less vertical erosion and

deposition shallow Length: ** more meanders exist longest Gradient : deposition gentle slope Wetted perimeter :very wide

Conclusion Description of channel geometryDescription of channel geometry

gradient Velocity Depth / Width / Length

A Steep Rapid Deep (vertical erosion)/ Narrow / Short

B Less steep

Slow Medium / Medium / Medium

C Gentle Rapid Shallow / Wide / Long

The End~~ Thank you!