Overbank Flood Routing Regularity for Transitional Stretch of Lower Yellow River

By use of the observed data from Gaocun—Sunkou reaches on the down stream of the Yellow River analysed the overbank flood routing regularity and the impact of transitional reach are analysed.The result shows that these transitional reaches are characterized by winding river channels,multi river floodplain,large area and poor linking and passing ability.By means of controlling and protecting projects of those flood plains,the main river channel has become stable,however,the distribution of siltation in the lateral direction is uneven.The main cause of the peak overbank flow deduction,change of the peakflow shape and change of the transition time is the different combinations of the abilities of flood storage and detention of floodplains,and the flood carrying capacity of the main river channel.