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Channel geometry of mountain streams

University of British Columbia

Channel networks in the glaciated mountain basins of Coastal and southern interior British Columbia (Ashnola River Basin) offer opportunities for morphometric studies relating the parameters of the flow area (A) - discharge (Q) relationship to readily available channel and basin parameters. Steady flow conditions in rough channels are approximated by equations of the form A = a[formula omitted]Q[formula omitted] . The parameters, a[formula omitted] and b[formula omitted], vary individually with each channel and are related to channel dimensions; a[formula omitted] = .94 W[formula omitted]·⁴⁷ and b[formula omitted] = .3 W[formula omitted]·¹⁷. These results are independent of climate and under normal conditions give excellent predictions of the Q-A relations for rough channels in both regions. The systematic variation of channel dimensions within a basin are related to drainage area:W[formula omitted] = 3.7 DA·[formula omitted] for coastal basins and W[formula omitted] = 1.3 DA[formula omitted] for Ashnola basins. The influence of climate is reflected in the constants, with areas of higher precipitation having larger constants. Drainage area can replace W[formula omitted]: a[formula omitted] = 1.74 DA[formula omitted] and b[formula omitted] = .37 DA[formula omitted]. These relations are applicable only within a climatically homogeneous region. In rough channels the Q-A relations are considered independent of slope, a result of energy dissipation through frequent hydraulic jumps. The hydromorphological equations developed here are valid only for rough channels where tumbling flow predominates.

Text

2011-05-27

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http://hdl.handle.net/2429/34941

Geography

University of British Columbia

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