Bankfull Discharge Recurrence Interval in Gravel-bed Rivers

✍ Scribed by Petit, F.; Pauquet, A.

• Book ID: 101219031
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 118 KB
• Volume: 22
• Category: Article
• ISSN: 0360-1269
• DOI: 10.1002/(sici)1096-9837(199707)22:7<685::aid-esp744>3.0.co;2-j

✦ Synopsis

Bankfull discharge was identified in some 30 gravel-bed rivers representing in total c. 40 gauging stations. The catchment sizes vary from 4 km 2 to nearly 2700 km 2 . Bankfull discharge value increases with basin size. In the case of gravel-bed rivers developed on an impermeable substratum, the following equation emerges:

Bankfull discharge recurrence interval was determined by fitting maximum annual floods (T a ) into Gumbel's distribution and then using the partial duration series (T p ) in this same distribution. Recurrence interval is below 0•7 years (T p ) for small pebble-bed rivers developed on an impermeable substratum; it reaches 1•1 to 1•5 years when the catchment size of these rivers exceeds 250 km 2 . Rivers incised in the soft schists of the Famenne show larger channel capacity at bankfull stage, a small width/ depth ratio and thus higher recurrence intervals (1•4-5•3 years with T a and 1-4•4 years with T p ). Baseflow-dominated gravel-bed streams and sandy or silty rivers experience less frequent bankfull discharges, with a recurrence interval higher than 2 or even 3 years (T p ).