Seasonal regime of bedform and hydraulic geometry, Lillooet River, Pemberton, British Columbia.

摘要

The aim of this thesis is to examine the seasonal regime of dune geometry and channel-bed elevations in a reach of Lillooet River, British Columbia, Canada. Measurements of dune height, length, steepness, water-depth and channel-bed elevation were made from echo-sounding profiles collected regularly during the 1995-1996 hydrologic year.; At least two different relations between dune geometry and discharge (or water-depth) exist for discharge events in which samples were collected. The two trends correspond to the less than, and greater than, 125 {dollar}rm msp{lcub}3{rcub}ssp{lcub}-1{rcub}{dollar} ranges of discharge. These trends may reflect how discharge is accommodated in the channel and how both sediment characteristics and supply vary with discharge.; No lag period exists between changes in discharge and dune geometry. Dune size is influenced by discharge events preceding the sample day.; As discharge changes, the channel-bed elevation responds in one of two ways: (1) fluctuating about a nearly horizontal average as discharge increases; (2) fluctuating about a horizontal average and decreasing only after a threshold discharge is exceeded.; The bed-elevation data vary out-of-phase with the field-season hydrograph. (Abstract shortened by UMI.)