Stream power

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

Empirical evidence of climate's role in Rocky Mountain landscape evolution

Abstract: [1] Climate may be the dominant factor affecting landscape evolution during the late Cenozoic, but models that connect climate and landscape evolution cannot be tested without precise ages of landforms. Zircon (U-Th)/He ages of clinker, metamorphosed rock formed by burning of underlying coal seams, provide constraints on the spatial and temporal patterns of Quaternary erosion in the Powder River basin of Wyoming and Montana. The age distribution of 86 sites shows two temporal patterns: (1) a bias toward younger ages because of erosion of older clinker and (2) periodic occurrence of coal fires likely corresponding with particular climatic regimes. Statistical t tests of the ages and spectral analyses of the age probability density function indicate that these episodes of frequent coal fires most likely correspond with times of high eccentricity in Earth's orbit, possibly driven by increased seasonality in the region causing increased erosion rates and coal exhumation. Correlation of ages with interglacial time periods is weaker. The correlations between climate and coal fires improve when only samples greater than 50 km from the front of the Bighorn Range, the site of the nearest alpine glaciation, are compared. Together, these results indicate that the interaction between upstream glaciation and downstream erosion is likely not the dominant control on Quaternary landscape evolution in the Powder River basin, particularly since 0.5 Ma. Instead, incision rates are likely controlled by the response of streams to climate shifts within the basin itself, possibly changes in local precipitation rates or frequency-magnitude distributions, with no discernable lag time between climate changes and landscape responses. Clinker ages are consistent with numerical models in which stream erosion is driven by fluctuations in stream power on thousand year timescales within the basins, possibly as a result of changing precipitation patterns, and is driven by regional rock uplift on million year timescales.

Predicting Channel Recovery from Sand and Gravel Extraction in the Naugatuck River and Adjacent Floodplain

Abstract: Gravel extraction at five sites along the Naugatuck River in Connecticut is of sufficient magnitude that channel recovery to pre-mining morphology is expected to require up to several hundred years for instream sites and longer for riparian pits. The bases for this prediction are: a geomorphic evaluation of the channel from sequential aerial photography; hydrographers' records of gaging stations in the basin; and limited calculations of bedload transport, based upon stream power - instantaneous transport rate relations. The pre-mining response of the channel to an extreme flood in 1955 was also examined to determine how the channel might adjust to major disturbance.

Study on Landscape Patches Influencing Hillslope Erosion Processes and Flow Hydrodynamics in the Loess Plateau of Western Shanxi Province, China

Abstract: Although vegetation restoration plays an important role in the management of surface runoff and soil erosion, the large-scale restoration of vegetation can increase water consumption and reduce surface water resources, thus affecting the health of river ecosystems. Therefore, vegetation restoration should aim to achieve a vegetation landscape pattern that optimizes protection of soil resources while limiting water consumption. This study established field runoff plots with different landscape patch types, including bare land, S-road patches, strip patches, grid patches, and random patches, as well as different quantities patches of 5, 10, 15, and 20. An artificial rainfall experiment was conducted to determine the effect of different vegetation patches in reducing runoff and sediment, and the relationship between the types and number of vegetation patches and hydrodynamic parameters. The results showed that the runoff yields of the four vegetation patch types decreased by 16.1–48.7% compared with that of bare land, whereas sediment yields decreased by 42.1–86.5%. In addition, the resistance coefficients of the poorly connected patch patterns, including strip patches, grid patches, and random patches, ranged between 0.2–1.17 times higher than that of the well-connected S-road patch pattern, and the stream power decreased by 33.3–50.7%. Under a set vegetation coverage rate, an increase in the number of vegetation patches resulted in a significant reduction in runoff velocity, runoff yield, and sediment yield, increases in surface roughness and flow resistance, and reductions in runoff shear force and stream power. Besides, the sensitivity of soil to erosion decreased with an increasing number of the patch in the vegetation landscape, whereas the sensitivities of patch combinations with poor connectivity were lower than those with good connectivity. The results of this study highlight the importance of vegetation patch type and quantity for control of soil erosion.

Influences of Tectonic Uplift and Climate Changes on the Yazheku River Terraces in the Eastern Tibetan Plateau

Abstract: Tectonic uplift and climate change are two key factors in controlling the development of river terraces in hinterlands.Rivers in different areas,however,correspond to them in various ways.The Haizi Shan,located in the central Shaluli Mountain,eastern Tibetan Plateau,experienced tectonic uplift of great amplitude and extensive glaciation during the Quaternary.Six order river terraces have been preserved on both bands of the Yazheku River in the northern margin of the Haizi Shan,while to the south are glacial sediments in the Daocheng River valley in the southern Haizi Shan.Electron Spin Resonance(ESR) was applied to date the sediments of the 4 higher terraces(T3~T6,from the lower to higher order) and the glacial sediments in the Daocheng River valley.The evolution process of the 4 terraces was analyzed on the basis of the dating results and the geomorphological and sedimentological characteristics of the terraces.The strath formation and sediment aggradation of the 4 terraces occurred during the period of glacier melting,which corresponds to the late period of deep-sea oxygen isotopic stages 2,6,12,and 16.With climate getting warmer,glaciers on the Haizi Shan gradually melted and disappeared eventually after climate turned into interglacial condition.As a result,the loading of the underlying crust dramatically decreased,which led to tectonic uplift and the deglaciation-induced isostatic uplift of the underlying crust.Accordingly,the longitudinal profile of the Yazheku River steepened,together with increased water supply resulting from the strengthened Indian monsoon precipitation,the stream power highly increased.Lesser amount of contemporary river sediment resulted in that previously deposited sediment and underlying basement were incised,thus forming a new terrace.The incision ratio of the Yazheku River was ~0.43 mm/a since late deep-sea isotope stage 16,less than the uplifting ratio(2 mm/a) of the Haizi Shan,which is consistent with the conclusion that the incision ratio is no more than the uplifting ratio.