Stream power

About: Stream power is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 51324 citations.

Mapping debris flow susceptibility using analytical network process in Kodaikkanal Hills, Tamil Nadu (India)

Abstract: Rapid debris flows, a mixture of unconsolidated sediments and water travelling at speeds > 10 m/s are the most destructive water related mass movements that affect hill and mountain regions. The predisposing factors setting the stage for the event are the availability of materials, type of materials, stream power, slope gradient, aspect and curvature, lithology, land use and land cover, lineament density, and drainage. Rainfall is the most common triggering factor that causes debris flow in the Palar subwatershed and seismicity is not considered as it is a stable continental region and moderate seismic zone. Also, there are no records of major seismic activities in the past. In this study, one of the less explored heuristic methods known as the analytical network process (ANP) is used to map the spatial propensity of debris flow. This method is based on top-down decision model and is a multi-criteria, decision-making tool that translates subjective assessment of relative importance to weights or scores and is implemented in the Palar subwatershed which is part of the Western Ghats in southern India. The results suggest that the factors influencing debris flow susceptibility in this region are the availability of material on the slope, peak flow, gradient of the slope, land use and land cover, and proximity to streams. Among all, peak discharge is identified as the chief factor causing debris flow. The use of micro-scale watersheds demonstrated in this study to develop the susceptibility map can be very effective for local level planning and land management.

Erosion, deposition and basin-wide variations in stream power and bed shear stress

Abstract: Field data from four separate locations indicate that the rate at which river channel gradient decreases downstream is fundamentally different in areas of long-term erosion and deposition. Gradient (S) and distance from the drainage divide (x) are related such that S is proportional to xΦ. In areas of deposition Φ −1.1. These differences produce downstream increases and decreases in stream power and bed shear stress which also coincide with areas of erosion and deposition. This is the first time that such a basin-wide coincidence has been demonstrated. A strong positive correlation between stream power, bed shear stress and bedload transport rates has been clearly shown by previous empirical studies of loose-bed channels. It is proposed that large-scale patterns of erosion and deposition in alluvial basins result from downstream changes in bedload transport rates, produced by the observed trends in these two parameters. If this proposal is to be fully tested, further work is needed to assess the affects of downstream fining of bed material, short-term fluctuations in discharge and downstream exchange of particles between the suspended load and bedload.