Assessment of Recent Lateral Channel Migration characteristics of the Lower Section of River Digil, Mubi North, Adamawa State, Nigeria

Dimensions of Holocene relict channels and sedimentological characteristics of point bars associated with these relict channels were used to reconstruct a Holocene history of long-term changes in magnitudes of 1.58-yr floods in Upper Mississippi Valley watersheds of southwestern Wisconsin. The reconstructed record of floods shows relatively large and persistent (nonrandom) departures from contemporary long-term average flood magnitudes. The flood history indicates climatic changes that are broadly similar to climatic changes indicated from fossil pollen in the same region. The Holocene floods ranged from about 10–15% larger to 20–30% smaller than contemporary floods of the same recurrence frequency. Large floods were characteristic between about 6000 – 4500 and 3000 – 2000 yr B.P., and during a brief interval after 1200 yr B.P. Small floods were common between about 8000 – 6500, 4500 – 3000, and 2000 – 1200 yr B.P. These fluvial responses were found to be closely associated with a long-term episodic mobility and storage of sediments in the Wisconsin watersheds. During periods of relatively large floods, relatively rapid lateral channel migration either reworked or removed extensive tracts of valley bottom alluvium. In contrast, during periods of relatively small floods, relatively slow lateral channel migration is apparent and the channel and floodplain system appear to have been relatively stable.

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Lateral channel migration effects on riparian forest structure and composition, Congaree River, South Carolina, USA

Wetlands ◽

10.1672/08-45.1 ◽

2009 ◽

Vol 29 (2) ◽

pp. 465-475 ◽

Cited By ~ 22

Author(s):

Kimberly M. Meitzen

Keyword(s):

South Carolina ◽

Forest Structure ◽

Riparian Forest ◽

Channel Migration ◽

Lateral Channel

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Controls on the lateral channel migration rate of braided alluvial channel systems

10.5194/egusphere-egu2020-10211 ◽

2020 ◽

Author(s):

Aaron Bufe ◽

Jens Turowski ◽

Douglas Burbank ◽

Chris Paola ◽

Andrew Wickert ◽

...

Keyword(s):

Boundary Conditions ◽

Migration Rate ◽

External Boundary ◽

Lateral Migration ◽

Channel Migration ◽

Channel System ◽

Migration Rates ◽

Lateral Channel ◽

Channel Slope ◽

Channel Systems

<p>Lateral movements of alluvial river channels control the extent and reworking rates of alluvial fans, floodplains, deltas, and alluvial sections of bedrock rivers. These lateral movements can occur by gradual channel migration or by sudden changes in channel position (avulsions). Whereas models exist for rates of river avulsion, we lack a detailed understanding of the rates of lateral channel migration on the scale of a channel belt. Here we develop, for the first time, an expression that describes the lateral migration rate of braided alluvial channels in non-cohesive sediment. On the basis of photographic and topographic data from laboratory experiments of braided channels performed under constant external boundary conditions, we first explore the impact of autogenic variations of the channel-system geometry (i.e., channel-bank heights, water depths, channel-system width, and channel slope) on channel-migration rates. In agreement with theoretical expectations, we find that, under such constant boundary conditions, lateral channel-migration rates scale inversely with the channel-bank height. Furthermore, when changes in channel-bank heights are accounted for, lateral migration rates appear independent of channel slope, channel-system width, and water depth. These constraints allow us to derive two dimensionally consistent expressions for lateral channel-migration rates under different boundary conditions. We find that migration rates are strongly sensitive to channel-bank heights and water discharges and more weakly sensitive to sediment discharges in braided equilibrium channel systems. In addition, the strong dependence of lateral migration rates on channel-bank heights implies that external perturbations (for example, perturbations of sediment and water discharges) that modulate the depth of channel incision and can indirectly affect lateral channel-migration rates.</p>

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Predicting River Floodplain and Lateral Channel Migration for Salmon Habitat Conservation

JAWRA Journal of the American Water Resources Association ◽

10.1111/j.1752-1688.2007.00063.x ◽

2007 ◽

Vol 43 (3) ◽

pp. 786-797 ◽

Cited By ~ 26

Author(s):

Jason E. Hall ◽

Damon M. Holzer ◽

Timothy J. Beechie

Keyword(s):

Habitat Conservation ◽

Channel Migration ◽

River Floodplain ◽

Lateral Channel

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A remote sensing-based evaluation of channel morphological characteristics of part of lower river Niger, Nigeria

SN Applied Sciences ◽

10.1007/s42452-021-04215-1 ◽

2021 ◽

Vol 3 (3) ◽

Author(s):

M. O. Ibitoye

Keyword(s):

Morphological Changes ◽

Morphological Characteristics ◽

River Channel ◽

Lower Section ◽

River Bank ◽

Spatial Changes ◽

Lateral Channel ◽

The Right ◽

Cost Implications ◽

River Niger

AbstractRiver bank erosion, accretion and lateral channel migration are important geomorphological processes, which attract a great deal of attention of river engineering scientists in many parts of the world. The present study assesses the morphological characteristics of parts of the lower section of River Niger, where field data are scarce and difficult to access for security and cost implications. Multi-date (1990, 2002 and 2017) Landsat imageries were used for the study, the imageries were corrected for geometric and radiometric errors, classified and analysed for changes in major land cover classes within the river channel, to assess river planform, riverbank pattern, channel width, bankline migration and centreline using ArcGIS software. The results revealed a decrease in water body and riparian vegetation by 27.64% and 9.77%, respectively, between 1990 and 2017. Sediment yield, however, increased by 75.61%. In addition, the river channel exhibited significant spatial changes within the study period; centreline at left flange shifted eastwards by about 1347.3 m at the upper section but westward at the lower section by 123.1 m. The bankline shifted prominently eastwards at right flange and westwards at the right flange. The study concluded that the studied channel had actually undergone some critical morphological changes greatly affected by erosion and accretion processes that are easily captured with remote sensed imageries.

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