Stream power

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

An integrated approach for evaluating the flash flood risk and potential erosion using the hydrologic indices and morpho-tectonic parameters

Abstract: An arid climate and lacking adequate flood management systems are the main reasons for flash flood events in arid and semi-arid areas. The study area is a part of the Sinai Peninsula in Egypt, Wadi Gharandal subjected to several flooded events during the past decades. The present study incorporated hydrologic indices and morpho-tectonic parameters to identify the potential sediment accumulation and erosion. Integration of hydrologic indices, stream power index, sediment transport, and topographic wetness indices with morpho-tectonic parameters to produce and detect erosion and sedimentation associated with flash floods is the main objective. Consequently, the geographic information system (GIS) and the fuzzy k-means clustering algorithm were implemented for spatial data classification and management. The applied method revealed that the hydrologic and morphometric parameters play major roles in flash flood contributing factors. The low slope areas are associated with low run-off connected with a high sediment accumulation. Conversely, a high level of erosion is encountered in the steeper slope areas. Furthermore, terrain and lithology are decisive in sediment accumulation and erosion risk in the study area. The present study demonstrates the hydrologic and morpho-tectonic parameters with remote sensing data set are efficient tools in evaluating flash floods, potential erosion, and management, supporting the urban planner for future development.

The Mekong River: Morphology, Evolution and Palaeoenvironment

Abstract: The Mekong, the largest river in Southeast Asia, shows striking variations in channel form and behaviour along its course. It appears to link several different types of channel rather than continuing in an orderly progression. Eight different river units have been identified along the lower 2000+ km of the river from the Chinese border to the sea across Southeast Asia. The exercise was carried out using satellite images, field visits, topographical maps, and various publications of the Mekong River Commission including large-scale river maps. The boundaries between such units are sharp and not gradual. They are different from each other depending on their morphological characteristics, their behaviour and whether the channel is bedrock-controlled. The Mekong flows for nearly 4000 km before being a freelymoving river with overbank flooding and course changes across the wide plain of Cambodia. Prior to that the channel is essentially structure-guided. It is a seasonal river with high flows during the southwestern monsoon and periodic floods late in the wet season. This linkage of several identifiable river units and the location of the present course of the river have not been properly explained. The estimated stream power of the Mekong in large floods seems to be very low when compared to what is required to erode a large channel in rock even along geological lineations. The opening of the South China Sea and the lowlands of Southeast Asia are associated with extrusion tectonics resulting from the Indian Plate colliding with the Eurasian Plate and building of the Himalaya Mountains from Eocene onwards. The present course of the river is likely to have been determined at least primarily from this event, and possibly also associated with stronger monsoon systems in the Early Holocene as recognised for South Asia. Morphology comparable to that of the Mekong seems to exist in several other major rivers of Southeast Asia and there could be a regional pattern, but investigation on this topic has hardly started.

Hydrogeomorphic and Biotic Drivers of Instream Wood Differ Across Sub‐basins of the Columbia River Basin, USA

Abstract: Instream wood promotes habitat heterogeneity through its influence on flow hydraulics and channel geomorphology. Within the Columbia River Basin, USA, wood is vital for the creation and maintenance of habitat for threatened salmonids. However, our understanding of the relative roles of the climatic, geomorphic, and ecological processes that source wood to streams is limited, making it difficult to identify baseline predictions of instream wood and create targets for stream restoration. Here, we investigate how instream wood frequency and volume differ between seven sub-basins of the interior Columbia River Basin and what processes shape these differences within these sub-basins. We collected data on wood volume and frequency, discharge and stream power, and riparian and watershed forest structure for use in modelling wood volume and frequency. Using random forest models, we found that mean annual precipitation, riparian tree cover, and the individual watershed were the most important predictors of wood volume and frequency. Within sub-basins, we used linear models, finding that some basins had unique predictors of wood. Discharge, watershed area, or precipitation often combined with forest cover, riparian conifer, and/or large tree cover in models of instream large wood volume and frequency. In many sub-basins, models showed at least one hydrologic variable, indicative of transport competence and one ecological variable, indicative of the reach or upstream watershed's capability to grow measurable instream wood. We conclude that basin-specific models yield important insights into the hydrologic and ecological processes that influence wood loads, creating tractable hypotheses for building predictive models of instream wood. Copyright © 2015 John Wiley & Sons, Ltd.

Modelling surface geomorphic processes using the RUSLE and specific stream power in a GIS framework, NE Peloponnese, Greece

Abstract: Mediterranean regions, with climate variability and long histories of human disturbance, are particularly vulnerable to soil erosion and sediment redistribution. This study examines surface soil stability and stream energy of the 243 km2 Inachos River watershed in the northeast Peloponnese, Greece. This mountainous, semi-arid Mediterranean region has an extensive history of human activity. Soil loss and stream energy are each quantified by applying the Revised Universal Soil Loss Equation (RUSLE) using the Unit Stream Power Erosion Deposition (USPED) method and the specific stream power approach to the main river channels. These models are used to indicate the spatial variability in geomorphic activity. Results show an average soil loss for the Inachos River catchment of 15.0 t ha−1 a−1, exceeding the rate of soil formation. Values range from nil in low gradient environments to 4287 t ha−1 a−1 in steep, mountainous regions. Gradient and rainfall erosivity are the primary factors. High specific stream power in the upper watershed exceeds 17,100 W m−2, resulting in the mobilization of sediment into channelized debris flows that transport sediment from the steep hillslopes. Episodic high-magnitude precipitation events promote the longitudinal connectivity of the catchment. The long occupation and agricultural history, extending as far back as Neolithic time, has accelerated downslope sediment transport.