1. BASIC SEDIMENT TRANSPORT AND RIVER MORPHOLOGY
6.2
BASIC SEDIMENT TRANSPORT AND RIVER MORPHOLOGY

2. STATEMENT: IN SPATE IRRIGATION MANAGING SEDIMENTATION IS AS IMPORTANT AS MANAGING WATER

3. THE WIDE FLOOD CHANNEL IN THE UPPER SECTION TYPICALLY CONTAINS A NUMBER OF LOW FLOOD CHANNELS – THAT ARE FORMED BY THE PRECEEDING HIGH FLOWS AND THE RECESSION FLOWS
IN THIS SECTION EPHEMERAL RIVERS CAN BE QUITE UNSTABLE AND EVEN CHANGE DIRECTION IN A HIGH FLOODS UNLESS THEY ARE CONTAINED – IN THESE AREAS EMBANKMENTS AND GUIDE BUNDS ARE IMPORTANT

4. BECAUSE OF SEEPAGE, CHANNEL STORAGE AND IRRIGATION ABSTRACTIONS, FLOODS FLOW REDUCE AS THEY PASS DOWN AND THE EPHEMERAL RIVER OFTEN REDUCES IN DEPTH IN THE LOWER SECTIONS

5. NEW BED LEVEL OLD BED LEVEL YANDOFERO RIVER, KONSO, ETHIOPIA
RIVER MORPHOLOGY GONE WRONG:AFTER THE CUTTING OF
A RIVERAINE FOREST THE YANDOFERO RIVER CHANGE ITS
DOWNSTREAM COURSE AND BED LEVELS DROPPED 1-3 METERS

6. SEDIMENT TRANSPORT

7. SEDIMENT LOADS OF 5% OF WEIGHT ARE COMMON IN FLOODS
HIGH FLOODS MAY CARRY AS MUCH AS 10%

8. WITHIN THE EPHEMERAL RIVER SYSTEM A MIX INCLUDING COARSE MATERIAL IS USUALLY FOUND IN THE UPPER SECTIONS

9. CLAYS AND FINE MATERIAL SETTLE MORE IN THE TAIL

10. The fine sediment in one irrigation may reach 15 cm height!