CGRG Bibliography of Canadian Geomorphology
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Author : Bovis, M.J.; and Dagg, B.R.
Date : 1988
Title : A model for debris accumulation and mobilization in steep mountain streams
Publication : Hydrological Sciences
Issue : 33(6):
Page(s) : 589-604.
Abstract
Previous work on the initiation of debris flows has emphasized the roles played by material strength, stream gradient, and fluid pressure, but in most published models the friction angle of the channel material is assigned some characteristic or constant value. A model is presented that retains gradient and pressure as variables, and considers the probable changes in friction angle and hydraulic conductivity, K, of channel debris over time. Preliminary results from the Howe Sound area in southwest British Columbia suggest that stream reworking may lead to small increases in friction angle and large increases in K, rendering channel debris more stable with time. This is partially offset by a local increase in channel gradient as debris accumulates. These factors favor the growth of large, marginally stable debris deposits, and may lead to high-magnitude, low-frequency debris torrents in channels not steep enough to produce torrents directly from hillslope failure events. An important part of this ongoing study is to monitor peak water levels associated with winter storms using rapid response pressure transducers. This program, combined with the measurement of spatial variability of high intensity rainfall, may clarify some of the important hydrological aspects of debris torrent initiation in the Howe Sound area.
Bibliography of Canadian Geomorphology