Vegetation and River Channel Dynamics

Hickin, Edward J.

doi:10.1111/j.1541-0064.1984.tb00779.x

Cited by 290 publications

(183 citation statements)

References 23 publications

Supporting

Mentioning

175

Contrasting

Unclassified

Order By: Relevance

“…Although it was clearly not a meandering river, it was shifting toward a meandering behavior rather than strictly braiding. It has proven quite difficult to model true meanders in a flume [Smith, 1998], and one of the main reasons may be lack of vegetation [Hickin, 1984]. In order to determine how strong the helical flow generated by oblique bank impingement might be we developed a simple model of an impingement-driven vortex.…”

Section: Methodsmentioning

confidence: 99%

Riparian vegetation controls on braided stream dynamics

Gran¹,

Paola²

2001

Water Resources Research

350

314

View full text Add to dashboard Cite

Abstract. Riparian vegetation can significantly influence the morphology of a river, affecting channel geometry and flow dynamics. To examine the effects of riparian vegetation on gravel bed braided streams, we conducted a series of physical experiments at the St. Anthony Falls Laboratory with varying densities of bar and bank vegetation. Water discharge, sediment discharge, and grain size were held constant between runs. For each run, we allowed a braided system to develop, then seeded the flume with alfalfa (Medicago sativa), allowed the seeds to grow, and then continued the run. We collected data on water depth, surface velocity, and bed elevation throughout each run using imagebased techniques designed to collect data over a large spatial area with minimal disturbance to the flow. Our results show that the influence of vegetation on overall river patterns varied systematically with the spatial density of plant stems. Vegetation reduced the number of active channels and increased bank stability, leading to lower lateral migration rates, narrower and deeper channels, and increased channel relief. These effects increased with vegetation density. Vegetation influenced flow dynamics, increasing the variance of flow direction in vegetated runs and increasing scour depths through strong downwelling where the flow collided with relatively resistant banks. This oblique bank collision also provides a new mechanism for producing secondary flows. We found it to be more important than the classical curvature-driven mechanism in vegetated runs.

show abstract

Section: Methodsmentioning

confidence: 99%

Riparian vegetation controls on braided stream dynamics

Gran¹,

Paola²

2001

Water Resources Research

350

314

View full text Add to dashboard Cite

show abstract

“…In fact, saltcedar was intentionally introduced to the Rio Puerco in 1926 to reduce damage caused by sedimentation in the Rio Environmental Management (2009) 44:218-227 225 Grande and in Elephant Butte Reservoir (Bryan and Post 1927;Pierce 1962). The importance of vegetation for bank stability is well known (Smith 1976;Hickin 1984;Simon and Collison 2002;Kean and Smith 2004). Measurements of the erosional consequences of vegetation removal at the riverreach scale, however, are scarce (Pollen-Bankhead and others 2009).…”

Section: Management Implicationsmentioning

confidence: 99%

Erosional Consequence of Saltcedar Control

Vincent

Friedman

Griffin

2009

Environmental Management

View full text Add to dashboard Cite

Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar (Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow (Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m 3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects.

show abstract

“…Additionally, the root systems of riparian plants help to stabilize streambanks by slowing or preventing streambank erosion (e.g. particle entrainment, mass wasting) (Simon and Collison, 2002;Murray and Paola, 2003), thereby reducing rates of channel migration for floodplain systems (Hickin, 1984;Micheli and Kirchner, 2002a). Recent studies have begun to report specific relationships relating the role of roots to streambank stability (Micheli and Kirchner, 2002b;Murray and Paola, 2003;Gray and Barker, 2004) as well as how these root systems are affected by environmental gradients (Dwire et al, 2004) and herbivores (Kauffman and Krueger, 1984;Belsky et al, 1999;Brookshire et al, 2002).…”

Section: Introductionmentioning

confidence: 99%