Stream power

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

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

Abstract: Stream power is a measure of the main driving forces acting in a channel and determines a river's capacity to transport sediment and perform geomorphic work. Recent digital elevation models allow the calculation of channel gradient and consequently stream power at unprecedented spatial resolution, opening promising and novel opportunities to investigate river geomorphic processes and forms. The present paper investigates the suitability of map-derived information on total and specific stream power (SSP) to identify dominant processes within the channel (i.e. erosion, transport or deposition). SSP has been already used to identify a threshold for channel stability. This paper tests this knowledge and investigates whether or not attributes of stream power profiles are statistically correlated with distinctive field morphological forms. Two gravel bed single-thread English rivers are used as case studies, the Lune and the Wye. Available deposition and erosion features surveyed in the field from 124 different locations are used to classify channel reaches as erosion, transport or deposition dominated. Meaningful patterns emerge between the stream power attributes and the field-based channel classification. An SSP threshold, which erosion is triggered, compares favourably with the ones in the literature. Information about upstream stream power profiles helps to determine the dominant processes. The joint configuration of local and upstream stream power information uniquely classifies reaches into four classes of different sensitivity to erosion and deposition. Copyright © 2013 John Wiley & Sons, Ltd.

The distribution and management of channelized streams in Denmark

Abstract: The Danish Watercourse Law of 1982 states that major river works and maintenance procedures must be planned and undertaken with regard to water quality and the physical form of the river channel. Fluvial geomorphology is an essential component of alternative procedures of river management which work with nature rather than against it. A survey of Danish stream channels has been produced by collating data obtained from maps, field surveys and engineering documents. This indicates that 97.8 per cent of Danish watercourses have been artificially straightened and that only 2.2 per cent (880 km) have natural morphological characteristics. The density of channel works is 300 times greater than in the U.S.A. and 15 times greater than in England and Wales. It is suggested that since there are only a few naturally sinuous channels in Denmark these should be given special consideration with regard to stream management practices. Measurements undertaken at approximately 300 sites in Denmark indicate five major processes of adjustment within straightened reaches. These adjustments include degradation of the channel bed with associated bank slumping, armouring of the bed, the development of a sinuous thalweg by the deposition of sediment at low gradients, and restoration of meanders. Channel stability is related to specific stream power and the results may be useful in predicting potential adjustments following channel straightening. Deposition in natural reaches below straightened channels often obliterates pool and riffle sequences but several channel adjustments may provide a greater variability of physical habitats than the initial uniform straightened channel; their significance for the biology of the watercourse is best considered before traditional management practices are carried out to control the adjustment.

Modeling Interrill Erosion on Unpaved Roads in the Loess Plateau of China

Abstract: Unpaved roads play an important role in soil loss in small watersheds. In order to assess the impact of these unpaved roads in the Loess Plateau of China, runoff and sediment yields from road-related sources must be quantified. Field rainfall simulation experiments were conducted under three slope gradients and five rainfall intensities on unpaved loess roads in a small watershed. Results showed that the runoff generation was very fast in loess road surface (time to runoff 0·8). Soil loss rates were decreased as surface loose materials were washed away during a rainstorm. Rainfall intensity, initial soil moisture, and slope gradient are key factors to model surface runoff and sediment yield. Soil loss on loess road surface could be estimated by a linear function of stream power (R2 = 0·907). Four commonly interrill erosion models were evaluated and compared, and the interrill erodibility adopted in the Water Erosion Prediction Project model was determined as 1·34 × 106 (kg s m−4). A new equation taking into account different parameters like rainfall intensity, surface flow discharge, and slope gradient was established. Copyright © 2013 John Wiley & Sons, Ltd.

Nonlinear Downstream Changes in Stream Power on Wisconsin's Blue River

Abstract: Spatial characteristics of stream power are examined along four stream reaches through the 208-km2 Blue River watershed in southwestern Wisconsin. Although prevailing theoretical arguments often use spatially aggregated data and power functions derived from hydraulic geometry to suggest that stream power increases linearly downstream, analysis of stream-power trends along the Blue River's spatially connected stream pathways in southern Wisconsin shows that these pathways exhibit varying degrees of nonlinearity in the downstream distribution of stream power. In three of the four stream pathways, cross-sectional stream power and mean stream power reach maximum values at drainage areas between 10 and 100 km2 before decreasing rapidly downstream. Geomorphic and lithologic controls, which produce unusually steep channel slopes in mid-basin locations, are primarily responsible for the nonlinear downstream trends in stream power. Wide valley bottoms and gentle channel gradients occur in erodible lithologies, whi...