Morphological field investigation of river bed changes Case study: Dez River Bed

The construction of the Dez dam caused a major decrease in the sediment load downstream from the dam, and this inevitably resulted in channel degradation, which has important implications for flood control, navigation conditions and aquatic ecology in the whole river basin. Based on analysis of field data and statistical calculation, estimates of the channel degradation in the Dez River downstream from the dam can bring many helpful information to engineering community. In this study it is proofed that 200 to 300 meter after the dam location has the most aggradation range while 100 to 200 meter and 300 to 500 meter after the dam degradation took place. Besides the correlation of river bed median size indicated that the bed didn’t change anymore in recent years of the study compare to initial years, so the forming of armor layer has started and the river bed grows in a stable form pattern.

Keywords:

Dez River , Bed changes , Scouring , Median size