Stream power

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

Impact of river interventions on alluvial channel morphology

Abstract: Rivers play a significant role for sustainment and development of human race. The number of river interventions is increasing to meet water and energy demand. The present paper discusses impacts of...

Morphology and mechanism of the very large dunes in the tidal reach of the Yangtze River, China

Abstract: High-resolution multibeam data was used to interpret the surface morphology of very large dunes (VLDs) in the tidal reach of the Yangtze River, China. These VLDs can be divided into three categories according to their surface morphological characteristics. (1) VLDs-I: those with a smooth surface and cross-section; (2) VLDs-II: those accompanied by secondary dunes; (3) VLDs-III: those accompanied by secondary dunes and numerous elliptical pits. Parameters and spatial distribution of VLDs, and bed surface sediment were analyzed in the laboratory. Overall, channel morphology is an important factor affecting the development of VLDs, and channels with narrow and straight and certain water surface slope are facilitating the development of VLDs by constraining stream power. Meanwhile, distribution density of VLDs depicts a decreasing trend from Chizhou towards the estuary, are probably influenced by channel morphology and width. Associated pits in VLDs-III change the 3D dune morphology by distributing in secondary dunes as beads. The Three Gorges Dam project (TGP) leads to the bed surface sediment activity frequently and leads to the riverbed surface sediment coarsens, which promotes the further development of dunes. Moreover, other human activities, such as river regulation project, sand mining and Deep Water Channel Regulation Project have changed the regional river boundary conditions and hydrodynamic conditions are influential on the development of VLDs.

Deriving and evaluating hydraulics and detachment models of rill erosion for some calcareous soils

Abstract: Rill erosion plays an important role in the amount of soil detachment and the transport sediment load on hillslope. Quantification of the soil erosion requires a more precise understanding of the processes and development of rill erosion models. The objective of this study was to derive and evaluate hydraulics and detachment models of rill erosion in calcareous soils of northwestern Iran. Rill erosion experiments were carried out at 55 locations with three replications under field conditions. At each point, the rill plots were created with a 0.2 m width and 4 m length on agricultural soils. The inflow rates were 4, 12, 20 and 30 l min−1 with varying slope from 4 to 25.5%. The results indicated that all conditions of flow regimes including sub- and super-critical (laminar and turbulent) were observed in created rills by overland flow. The mean flow velocity and rill depth have been described well by flow rate and slope gradient, while rill width and flow depth have been explained well by flow rate. The prediction detachment rate by rill flow based on stream power model by non-linear regression yielded the best results (R2 = 0.545 and RMSE = 0.00213 kg m−2 s−1) for all combinations of slope classes. However, there are no significant differences between prediction accuracy of linear and non-linear models, when individual slope classes were considered.

Cosmogenic 10Be and OSL dating of fluvial strath terraces along the Osip-cheon River, Korea: tectonic implications

Abstract: The Osip-cheon River flows along a linear valley that runs approximately parallel to the Osip-cheon Fault. The present study was undertaken to elucidate the tectono-geomorphic evolution of the Osip-cheon Basin during the late Quaternary by employing cosmogenic 10Be surface exposure dating and optically stimulated luminescence (OSL) dating on a flight of fluvial strath terraces. Several morphometric indices (e.g., stream length-gradient index, asymmetry factor, transverse topographic symmetry factor, stream power incision) for relative tectonic activity are determined with the help of GIS analysis, suggesting minimal tilt of the blocks on either side of the Osip-cheon Fault, with displacement being mainly strike-slip. Thus, it is suggested that the Osipcheon River is a kind of subsequent stream that follows the weakened fault-line in the center of the basin. To determine the fluvial incision rate as an equivalent to the rate of local tectonic uplift, samples for cosmogenic 10Be dating and OSL dating were collected from the surfaces of strath terraces at two different areas along the Osip-cheon River. The terraces can be divided into three groups (T1: oldest to T3: youngest) depending on the height above the present river level. According to our data, the strath terraces formed at ca. 200 ka for T1, ca. 104 ka for T2, and ca. 14 ka for T3. The fluvial incision rate was determined by dividing the height of the terraces above the river by their respective ages. The fluvial incision rate has decreased over the last 200 ka, with a maximum rate of 0.28 mm/yr occurring between T1 and T2 (i.e., ca. 200 ka to 104 ka) followed by a rate of 0.21 mm/yr for the period from T2 to T3 (i.e., ca. 104 ka to ca. 14 ka), and a minimum rate of 0.17 mm/yr since the abandonment of T3 (i.e., over the last 14 ka). Tong-ri Canyon is deeply incised up to the major knickpoint of the Mi-in Falls. Here, the rock-cut strath terraces can be divided into two groups: the farther upstream part of the Tong-ri area (Site-1) was dated to 5.5 ± 0.5 ka, equivalent to the incision rate of 0.26 mm/yr, and the downstream part of the Tong-ri area (Site-5) was dated to 18.5 ± 1.8 ka, equivalent to the incision rate of 0.23 mm/yr. Given the active upstream migration of the knickpoint (Mi-in Falls) found in the upper reach of the river, the incision rate provided by the ages of the strath terraces in the Tong-ri Canyon should be higher than that for any other reach of the river. However, the incision rate of the reach below the mouth of Tong-ri Canyon is similar to the value of the reach above the major knickpoint, suggesting that knickpoint migration in the Tong-ri area was not active during the last 18.5 ka. Rather, it seems to have advanced to a certain level of incision in the past. Along the Osip-cheon River, the values of stream power incision and stream length-gradient show a contrasting distribution. The highest and most anomalous values of these indices are found along the upstream part of the Osip-cheon River. These indices values are likely to be associated with stream piracy. Given the geomorphic features (e.g., elbow of capture, wind gap, waterfall) found in the Tong-ri Canyon area, stream piracy might have been caused by Quaternary reactivation of the Osip-cheon Fault or by the ongoing but slowing, long-term regional tectonic uplift, with an axis along the Taebaek Mountain Range.