| Abstract/Description or Keywords |
The morphodynamics of the anastomosing channel system of upper Columbia River in southeastern British Columbia, Canada, is examined using an adaptation of conventional hydraulic geometry termed ‘interchannel hydraulic geometry’. Interchannel hydraulic geometry has some of the characteristics of downstream hydraulic geometry but differs in that it describes the general bankfull channel form and hydraulics of primary and secondary channels in the anastomosing channel system. Interchannel hydraulic geometry generalizes these relationships and as such becomes a model of the geomorphology of channel division and combination. Interchannel hydraulic geometry of upper Columbia River, based on řeld measurements of Ŗow velocity and channel form at 16 test sections, is described well by simple power functions: wbf = 3Š24Qbf0Š64; dbf = 1Š04Qbf0Š19; vbf = 0Š30Qbf0Š17. These results, with other related measurements of Ŗow resistance, imply that channel splitting leads to hydraulic inefřciency (higher Ŗow resistance) on the anastomosing Columbia River. Because these řndings differ from those reported in studies elsewhere, we conclude that hydraulic efřciency does not provide a general explanation for anabranching in river channels. hydraulic geometry; hydraulic efřciency; anastomosing river |
