Gravel sediment routing from widespread, low- intensity landscape disturbance, Current River Basin, Missouri

Abstract

During the last 160 years, land‐use changes in the Ozarks have had the potential to cause widespread, low‐intensity delivery of excess amounts of gravel‐sized sediment to stream channels. Previous studies have indicated that this excess gravel bedload is moving in wave‐like forms through Ozarks drainage basins. The longitudinal, areal distribution of gravel bars along 160 km of the Current River, Missouri, was evaluated to determine the relative effects of valley‐scale controls, tributary basin characteristics, and lagged sediment transport in creating areas of gravel accumulations. The longitudinal distribution of gravel‐bar area shows a broad scale wave‐like form with increases in gravel‐bar area weakly associated with tributary junctions. Secondary peaks of gravel area with 1·8–4·1 km spacing (disturbance reaches) are superimposed on the broad form. Variations in valley width explain some, but not all, of the short‐spacing variation in gravel‐bar area. Among variables describing tributary drainage basin morphometry, present‐day land use and geologic characteristics, only drainage area and road density relate even weakly to gravel‐bar areal inventories. A simple, channel network‐based sediment routing model shows that many of the features of the observed longitudinal gravel distribution can be replicated by uniform transport of sediment from widespread disturbances through a channel network. These results indicate that lagged sediment transport may have a dominant effect on the synoptic spatial distribution of gravel in Ozarks streams; present‐day land uses are only weakly associated with present‐day gravel inventories; and valley‐scale characteristics have secondary controls on gravel accumulations in disturbance reaches. Copyright © 1999 John Wiley & Sons, Ltd.

Tributaries and the Management of Main‐Stem Geomorphology

“…We think that the most important challenge is to understand sediment routing through the channel network. This can be achieved through both the development of theoretical tools that address this spatial scale (Benda and Dunne, 1997;Sklar et al, 2006) and field observations and measurements of channel responses to disturbed sediment regimes in adjusting river systems (Jacobson and Gran, 1999;Kasai et al, 2004). It is the confrontation of such approaches that will give us the opportunity to develop and test decision-making tools adapted for the integrative management of fluvial systems.…”

“…landslides and bank erosion). Thus, in some catchments, it has been demonstrated that tributaries only have a small effect on the longitudinal patterns of main-stem morphology and sedimentology, these patterns being mostly controlled by the processes of sediment-wave propagation through the drainage network (Jacobson and Gran, 1999). The diachronic study of the changing nature of tributaries is presented as a possible approach for evaluating their geomorphic impact.…”

Ecoregions and stream morphology in eastern Oklahoma

“…In gravel-bed streams the downstream fining of bed material does not always occur orderly because of the influence of tributaries, large woody debris, and colluvial deposits (Dawson, 1988;Rice and Church, 1996;Powell, 1998). Land use disturbance in the Missouri Ozark Highlands is responsible for increased sediment in select basins, which has led to increased sediment routing through the system (Jacobson and Gran, 1999).…”

Development of sediment slug upstream from the Czorsztyn Reservoir (southern Poland) and its interaction with river morphology

“…The slugs may be generated through riverbed or bank erosion (endoslugs), or they may be formed by sediments from sources external to the river (exoslugs); furthermore, they may be associated with minor (macroslugs) or major (megaslugs) channel changes, or a major valley-floor adjustment (superslugs) (Nicholas et al, 1995). For example, in single-thread, gravel-bed rivers the process-form interaction between deposited bars and channel banks may lead to bank erosion (Nicholas et al, 1995;Wathen and Hoey, 1998;Klösch et al, 2015) and result in an increased local channel instability leading to the increased remobilization of floodplain sediments (Jacobson and Gran, 1999), causing channel widening or shallowing (Hoey, 1994;Wathen and Hoey, 1998;Klösch et al, 2015) and bend initiation (Leopold et al, 1964). This bar-bank interaction, in turn, may increase the magnitude of the initial sediment forms (Wathen and Hoey, 1998;Klösch et al, 2015).…”