scholarly journals Development of gullies on the landscape: A model of headcut retreat resulting from plunge pool erosion

2006 ◽  
Vol 111 (F1) ◽  
Author(s):  
Javier H. Flores-Cervantes ◽  
Erkan Istanbulluoglu ◽  
Rafael L. Bras
Keyword(s):  
Plunge Pool ◽  
Headcut Retreat

scholarly journals A Mechanistic Model of Waterfall Plunge Pool Erosion into Bedrock

2017 ◽  
Vol 122 (11) ◽  
pp. 2079-2104 ◽  
Author(s):  
Joel S. Scheingross ◽  
Michael P. Lamb
Keyword(s):  
Mechanistic Model ◽  
Plunge Pool

Mass balance controls on sediment scour and bedrock erosion in waterfall plunge pools

Geology ◽  
2021 ◽  
Author(s):  
Joel S. Scheingross ◽  
Michael P. Lamb
Keyword(s):  
Sediment Transport ◽  
Mass Balance ◽  
River Discharge ◽  
Sediment Load ◽  
Sediment Flux ◽  
Habitat Availability ◽  
Flux Divergence ◽  
Plunge Pool ◽  
Bedrock Erosion ◽  
Recurrence Intervals

Waterfall plunge pools experience cycles of sediment aggradation and scour that modulate bedrock erosion, habitat availability, and hazard potential. We calculate sediment flux divergence to evaluate the conditions under which pools deposit and scour sediment by comparing the sediment transport capacities of waterfall plunge pools (Qsc_pool) and their adjacent river reaches (Qsc_river). Results show that pools fill with sediment at low river discharge because the waterfall jet is not strong enough to transport the supplied sediment load out of the pool. As discharge increases, the waterfall jet strengthens, allowing pools to transport sediment at greater rates than in adjacent river reaches. This causes sediment scour from pools and bar building at the downstream pool boundary. While pools may be partially emptied of sediment at modest discharge, floods with recurrence intervals >10 yr are typically required for pools to scour to bedrock. These results allow new constraints on paleodischarge estimates made from sediment deposited in plunge pool bars and suggest that bedrock erosion at waterfalls with plunge pools occurs during larger floods than in river reaches lacking waterfalls.

scholarly journals Experimental migration of knickpoints: influence of style of base-level fall and bed lithology

2016 ◽  
Vol 4 (1) ◽  
pp. 11-23 ◽  
Author(s):  
J.-L. Grimaud ◽  
C. Paola ◽  
V. Voller
Keyword(s):  
Fall Rate ◽  
Pool Depth ◽  
Similar Shape ◽  
Base Level ◽  
Self Organized ◽  
Plunge Pool ◽  
Source To Sink ◽  
Constant Rate ◽  
Geomorphic Features ◽  
River Profiles

Abstract. Knickpoints are fascinating and common geomorphic features whose dynamics influence the development of landscapes and source-to-sink systems – in particular the upstream propagation of erosion. Here, we study river profiles and associated knickpoints experimentally in a microflume filled with a cohesive substrate made of silica, water and kaolinite. We focus on the effect on knickpoint dynamics of varying the distribution of base-level fall (rate, increment, and period) and substrate strength, i.e., kaolinite content. Such simple cases are directly comparable to both bedrock and alluvial river systems. Under a constant rate of base-level fall, knickpoints of similar shape are periodically generated, highlighting self-organized dynamics in which steady forcing leads to multiple knickpoint events. Temporary shielding of the bed by alluvium controls the spacing between these unit knickpoints. Shielding is, however, not effective when base-level drops exceed alluvium thickness. While the base-level fall rate controls the overall slope of experiments, it is not instrumental in dictating the major characteristics of unit knickpoints. Instead the velocity, face slope and associated plunge pool depth of these knickpoints are all strongly influenced by lithology. The period between knickpoints is set by both alluvium thickness and base-level fall rate, allowing use of knickpoint spacing along rivers as an indicator of base-level fall rate.

scholarly journals Experimental investigation of the effect of flip bucket splitters on plunge pool geometry

2010 ◽  
Vol 100 (4) ◽  
pp. 110-112 ◽  
Author(s):  
Sébastien Erpicum ◽  
Pierre Archambeau ◽  
Benjamin Dewals ◽  
Michel Pirotton
Keyword(s):  
Experimental Investigation ◽  
Plunge Pool

scholarly journals Numerical Simulation of the Hydraulic Performances and Flow Pattern of Swallow-Tailed Flip Bucket

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Lifang Zhang ◽  
Jianmin Zhang ◽  
Yakun Guo ◽  
Yong Peng
Keyword(s):  
Pressure Distribution ◽  
Flow Pattern ◽  
Width Ratio ◽  
Unit Discharge ◽  
Plunge Pool ◽  
Strip Shape ◽  
Pressure Peak ◽  
The Impact ◽  
Discharge Distribution ◽  
Opening Width

In this study, the evolution process of the swallow-tailed flip bucket water nappe entering into the plunge pool is simulated by using the standard k-ε turbulence model and the volume-of-fluid method. The effects of the upstream opening width ratio and downstream bucket angle on the flow pattern, the unit discharge distribution, and the impact pressure distribution are studied. Based on the numerical results, the inner and outer jet trajectories are proposed by using the data. Results show that the longitudinal stretching length decreases with the increase of the upstream opening width ratio and increases with the increase of the downstream bucket angle. The water nappe enters the plunge pool in a long strip shape. Thus, the unit discharge distribution of water nappe entry is consistent with the pressure distribution at the plunge pool bottom. The upstream opening width ratio and downstream bucket angle should be chosen as their intermediate values in order to have a uniform discharge distribution and to reduce the pressure peak at the plunge pool floor, which is effectively to avoid instability and destruction of plunge pool floor.

scholarly journals Experimental Study on the Air Concentration Distribution of Aerated Jet Flows in a Plunge Pool

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1779 ◽  
Author(s):  
Weilin Xu ◽  
Chunqi Chen ◽  
Wangru Wei
Keyword(s):  
Concentration Distribution ◽  
Discharge Rate ◽  
Lateral Diffusion ◽  
Jet Flows ◽  
Analysis Model ◽  
Air Concentration ◽  
Initial Flow ◽  
Plunge Pool ◽  
Physical Experiments ◽  
Air Diffusion

There is a lack of knowledge on the air concentration distribution in plunge pools affected by aerated jets. A set of physical experiments was performed on vertical submerged aerated jet flows impinging a plunge pool. The air concentration distribution in the plunge pool was analyzed under different inflow air concentrations, flow velocities, and discharge rate conditions. The experimental results show that the air concentration distribution follows a power-law along the jet axis, and it is independent of the initial flow conditions. A new hypothetical analysis model was proposed for air diffusion in the plunge pool, that is, the air concentration distribution in the plunge pool is superposed by the lateral diffusion of three stages of the aerated jet motion. A set of formulas was proposed to predict the air concentration distribution in the plunge pool, the results of which showed good agreement with the experimental data.

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