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 flow variability on the morphology of a low-energy meandering river

Abstract: Few studies have precisely documented the response of stream channels to short-term flow variability. This paper examines the impact of sequential flows of various magnitudes on the morphology of a low-energy river in northeastern Illinois, U.S.A. Between June 1986 and November 1988 channel cross-sections were surveyed on a semiannual basis at 26 locations along a 7.2 km stretch of the Des Plaines River. During this period an estimated 100-year flood, several bankfull flows, and an extreme low flow associated with a severe drought occurred. The response of the river channel to each of these events was relatively minor. Mean changes for the reach were generally less than 3 per cent for mean depth and less than 1 per cent for width. Statistical analysis indicates that net changes in width and depth over the entire period were not significantly different from zero. This lack of geomorphic response is attributable to low stream power, low hydrologic variability, fine bed materials, and cohesive banks along this stretch of river. Although dramatic changes in channel morphology did not occur, subtleties in geomorphic response were observed that reflect the temporal ordering of hydrologic events.

Modeling the effects of variable annual flow on river channel meander migration patterns, sacramento river, California, USA

Abstract: Flow regulation impacts the ecology of major rivers in various ways, including altering river channel migration patterns. Many current meander migration models employ a constant annual flow or dominant discharge value. To assess how flow regulation alters river function, variable annual flows -based on an empirical relationship between bank erosion rates and cumulative effective stream power - were added into an existing migration model. This enhanced model was used to evaluate the potential geomorphic and ecological consequences of four regulated flow scenarios (i.e., different hydrographs) currently being proposed on the Sacramento River in California. The observed rate of land reworked correlated significantly with observed cumulative effective stream power during seven time increments from 1956 to 1975 (r 2 = 0.74, p = 0.02). The river was observed to rework 3.0 ha/yr of land (a mean channel migration rate of 7.7 m/yr) with rates ranging from 0.8 ha/yr to 5.1 ha/yr (2.0 to 13.3 m/yr), during the analyzed time periods. Modeled rates of land reworked correlated significantly with observed rates of land reworked for the variable flow model (r 2 = 0.78, p = 0.009). The meander migration scenario modeling predicted a difference of 1 to 8 percent between the four flow management scenarios and the base scenario.

A theoretical model for fluvial channel response time during time-dependent climatic and tectonic forcing and its inverse applications

Abstract: The fluvial response time dictates the duration of fluvial channel adjustment in response to changing climatic and tectonic conditions. However, when these conditions vary continuously, the channel cannot equilibrate and the response time is not well defined. Here I develop an analytical solution to the linear stream power model of fluvial incision that predicts the channel topography as a function of time-dependent climatic and tectonic conditions. From this solution, a general definition of the fluvial response time emerges: the duration over which the tectonic history needs to be known to evaluate channel topography. This new definition is used in linear inversion schemes for inferring climatic or tectonic histories from river long profiles. The analytic solution further reveals that high-frequency climatic oscillations, such as Milankovitch cycles, are not expected to leave significant fingerprints on the long profiles of fluvially incised detachment-limited rivers.