ABSTRACT: DEM-based stream power estimates for fluvial erosion hazard.

CGRG Bibliography of Canadian Geomorphology
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Abstract

Large floods often have very large total sediment loads and cause major changes to river channel and floodplain morphology. Total (or cross-sectional) stream power represents the total, instantaneous energy available for geomorphic work in a channel, and, integrated over a flood event could provide an estimate of total event-related work. For a given catchment, the peak stream power for an event may be a good index approximation for the total work. Total stream power can be estimated from flood discharge and local channel (or water surface) gradient. Gradient can be derived from DEM data and discharge from a variety of methods based on DEM analysis of upstream drainage area. Together these can be used to map the spatial pattern of peak stream power, and along-channel changes in stream power. This is illustrated using a case of extreme increases in flood power from an urbanized catchment in Toronto in which local stream power at regulatory flood levels exceeds 104 (and possibly 105) W m-1. These estimates compare well with those derived from a standard1D open channel hydraulic model and with reaches known to have experienced catastrophic erosion during a recent extreme flood. In future this could be extended to unit stream power for sediment load estimates and to event-integrated geomorphic work.

Bibliography of Canadian Geomorphology