Sediment reworking in streambeds with fine sediment deposits and its influence on hyporheic flow regime

Effect of sediment-organism interactions on hyporheic exchange in streams: role of sediment reworking time

10.5194/egusphere-egu21-12699 ◽

2021 ◽

Author(s):

Shivansh Shrivastava ◽

Michael Stewardson ◽

Meenakshi Arora

Keyword(s):

Flow Regime ◽

Experimental Work ◽

Laboratory Experiments ◽

Hyporheic Exchange ◽

Residence Times ◽

Sediment Reworking ◽

Hyporheic Flow ◽

Mean Residence Times ◽

Organism Interactions

In-stream faunal organisms constantly interact with their habitat to modify its physical and hydraulic properties. However, little is known about how sediment-organism interactions could modify the hyporheic exchange. Previous experimental work investigating the effects of the activities of faunal organisms on exchange across the sediment-water interface has been largely conducted in small mesocosms or infiltration columns that do not represent the lotic environment adequately. Therefore, the experimental findings from these studies may not be transferable to flowing water environments (e.g., streams). Our previous experimental work demonstrated that sediment reworking by macroinvertebrates could significantly alter the hyporheic flux, mean residence times, and depth of exchange in streambeds. In this work, we explore how sediment-organism contact time influence the effect of the activities of model organisms, Lumbriculus variegatus, on the hyporheic flow regime. We conduct laboratory experiments in re-circulating flumes subject to different sediment reworking times (5 and 10 days). The hyporheic flow characteristics in these flumes were studied by conducting dye tracer tests after the bed sediments were reworked. Deposition of fecal pellets and holes/burrows dug by sample organisms were visible at the bed surface in both the experimental flumes. The flume reworked for a longer time exhibited higher hyporheic flux, longer median/mean residence times, and deeper depth of solute penetration compared to the flume reworked for a shorter period. The modification of hyporheic flow regime to different degrees depending on the sediment reworking times has direct relevance to the biogeochemistry in hyporheic zones, and thus on the overall quality of surface and sub-surface waters. We advocate that more intensive laboratory experiments and field investigations must be conducted to support the findings from our study and advance our understanding of the role of the activities of faunal organisms on fluvial ecosystem functioning.

Download Full-text

Estimation of Holocene bedload sedimentation rate in a paleo-drowned river-valley (Middle Harbour, Sydney estuary, Australia)

10.21203/rs.3.rs-1168446/v1 ◽

2022 ◽

Author(s):

Stephen P Lound ◽

Gavin F Birch ◽

Deirdre Dragovich

Keyword(s):

Seismic Data ◽

Fine Sediment ◽

River Valley ◽

Sedimentation Rates ◽

Suspended Material ◽

Last Glacial Period ◽

Sediment Deposits ◽

Sydney Estuary ◽

Over The Top ◽

The Last Glacial

Abstract Middle Harbour is a drowned-river valley located adjacent to the larger Sydney estuary, Australia. Extensive, high-resolution seismic data were correlated with borehole, land use, topographical, and geological data to calculate the mass of genetically different sediment deposits in Middle Harbour. The Harbour follows a well-defined drowned river-valley structure featuring small fluvial bedload delta deposits in the upper reaches of the embayments, a deep, central extensive mud basin overlying transgressive basal accumulations and a large flood-tide delta at the entrance. Deposits of an estimated 5,094 t of bedload, 21,143 t of suspended sediment and 5,947 t of transgressive basal material located in the estuary provided sedimentation rates of 0.68 t y-1, 1.29 t y-1, and 2.86 t y -1 respectively. These rates, determined from measured accumulations, were surprisingly low and substantially smaller than modelled rates. However, low sedimentation rates for suspended material may be due to fine sediment escaping over the top of the marine tidal delta, which effectively traps all bedload material from exiting the Harbour. Results of this study indicate that Holocene bedload sedimentation in Middle Harbour was slow and regular until a rapid increase after urbanisation commenced in the catchment. Most pre-Holocene material was eroded from Middle Harbour during the Last Glacial period with sediment currently present in the estuary having been deposited since sea-level recovery.

Download Full-text

Morphological resilience to flow fluctuations of fine sediment deposits in bank lateral cavities

Advances in Water Resources ◽

10.1016/j.advwatres.2018.03.004 ◽

2018 ◽

Vol 115 ◽

pp. 44-59 ◽

Cited By ~ 10

Author(s):

C. Juez ◽

M. Thalmann ◽

A.J. Schleiss ◽

M.J. Franca

Keyword(s):

Fine Sediment ◽

Flow Fluctuations ◽

Sediment Deposits

Download Full-text

Erodibility of fine sediment deposits in gravel bed rivers: investigation of the spatial variability

10.5194/egusphere-egu21-6103 ◽

2021 ◽

Author(s):

Hanna Haddad ◽

Magali Jodeau ◽

Germain Antoine ◽

Cédric Legoût

Keyword(s):

Spatial Variability ◽

Spatial Organization ◽

Fine Sediment ◽

Aquatic Life ◽

Vegetation Growth ◽

Gravel Bed ◽

Fine Sediments ◽

Sediment Deposits ◽

Low Altitude ◽

Gravel Bed Rivers

Fine sediments exhibit various stages of deposition and erosion during their transport from hillslopes to the ocean. In mountainous environments, high fine sediment load during runoff or dam flushing events can lead to important amounts of deposits in gravel bed rivers. Massive deposits may lead to bar elevation, riparian vegetation growth and consequently to bar stabilization, which can increase flood risks. High amount of fine sediment deposits alters also aquatic life and habitat.In order to better understand the dynamics of re-suspension of these deposits, and to accurately predict it with numerical modelling, field monitoring campaigns were performed to assess both the spatial variability and the controlling factors of the erodibility of fine deposits. The cohesive strength-meter (CSM) device, a pocket penetrometer and a pocket shear vane were used to evaluate the erodibility of fine sediments deposited in two rivers in the French Alps: The Is&#232;re and Galabre.The results highlight the specificity of gravel bed rivers with an abundance of areas of deposition of fine sediments, which are discontinuous compared to estuaries and lowland rivers. A high spatial variability of the erodibility was observed and related to the spatial organization of the deposits. The location of the deposit and its elevation, the moisture and the grain sizes are inter-related and have important correlations with the erodibility. Measurements show that high altitude dry deposits and low altitude humid deposits are more easily eroded than intermediate deposits with medium moisture. The measured variables explain part of the variability of the erodibility but other processes such as the history or the origin of the deposit might also be important factors to consider.

Download Full-text

Erosion behaviour of fine sediment deposits

Canadian Journal of Civil Engineering ◽

10.1139/l04-054 ◽

2004 ◽

Vol 31 (5) ◽

pp. 759-766 ◽

Cited By ~ 2

Author(s):

Bommanna G Krishnappan

Keyword(s):

Shear Stress ◽

Steady State ◽

Maximum Concentration ◽

Fine Sediment ◽

Bed Shear Stress ◽

Steady State Concentration ◽

Sediment Deposits ◽

Dilute Suspension ◽

The Difference ◽

State Concentration

Erosion characteristics of fine sediment deposits were studied experimentally using a rotating circular flume in the laboratory. The influence of the rate of application of bed shear stress and the structure of sediment beds was investigated. When the shear stress was applied suddenly on a bed formed by placing a thick slurry of kaolin in the flume, the concentration of the eroded sediment first increased to reach a maximum value, and then it started to decrease and finally attained a steady state value that was significantly lower than the maximum concentration (the steady state concentration value was one third of the maximum concentration value). When the shear stress was applied gradually, the behaviour was similar, but the difference between the values of the maximum concentration and steady state concentration was very small (<10%). When the shear stress was applied gradually on a bed formed by depositing a dilute suspension, the concentration increased monotonically and reached the steady state concentration without exhibiting the hump. Such a behaviour was attributed to the sorting of flocs in the settling of dilute suspension in which stronger flocs deposit first followed by weaker flocs in succession.Key words: kaolin, erosion rate, bed shear stress, bed structure, rotating circular flume, flocculation, size distribution.

Download Full-text

Effects of fine sediment, hyporheic flow, and spawning site characteristics on survival and development of bull trout embryos

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0372 ◽

2014 ◽

Vol 71 (7) ◽

pp. 1059-1071 ◽

Cited By ~ 16

Author(s):

Tracy Bowerman ◽

Bethany T. Neilson ◽

Phaedra Budy

Keyword(s):

Early Life ◽

Life Stage ◽

Early Life Stage ◽

Fine Sediment ◽

Bull Trout ◽

Egg Survival ◽

Embryo Survival ◽

Hyporheic Flow ◽

Spawning Site ◽

Spawning Sites

Successful spawning is imperative for the persistence of salmonid populations, but relatively little research has been conducted to evaluate factors affecting early life-stage survival for bull trout (Salvelinus confluentus), a threatened char. We conducted a field experiment to assess the relationship between site-specific environmental factors and bull trout embryo survival and fry emergence timing. Survival from egg to hatch was negatively related to percent fine sediment (<1 mm) in the redd and positively related to the strength of downwelling at spawning sites. Survival of eggs to fry emergence was also negatively related to fine sediment, and the best statistical models included additional variables that described the rate of downwelling and intragravel flow within the incubation environment. Fry emerged at an earlier stage in development from redds with high percentages of fine sediment. Increased hydraulic conductivity via redd construction and selection of spawning sites with strong downwelling appear to enhance hyporheic flow rates and bull trout egg survival, but early life-stage success may ultimately be limited by intrusion of fine sediment into the incubation environment.

Download Full-text

Channel narrowing by inset floodplain formation of the lower Green River in the Canyonlands region, Utah

Geological Society of America Bulletin ◽

10.1130/b35233.1 ◽

2020 ◽

Vol 132 (11-12) ◽

pp. 2333-2352 ◽

Cited By ~ 2

Author(s):

Alexander E. Walker ◽

Johnnie N. Moore ◽

Paul E. Grams ◽

David J. Dean ◽

John C. Schmidt

Keyword(s):

Flow Regime ◽

Flood Control ◽

Fine Sediment ◽

Sediment Flux ◽

Green River ◽

Channel Narrowing ◽

Flaming Gorge ◽

Snowmelt Flood ◽

Air Photo ◽

New Phase

Abstract The lower Green River episodically narrowed between the mid-1930s and present day through deposition of new floodplains within a wider channel that had been established and/or maintained during the early twentieth century pluvial period. Comparison of air photos spanning a 74-yr period (1940–2014) and covering a 61 km study area shows that the channel narrowed by 12% from 138 ± 3.4 m to 122 ± 2.1 m. Stratigraphic and sedimentologic analysis and tree ring dating of a floodplain trench corroborates the air photo analysis and suggests that the initial phase of floodplain formation began by the mid-1930s, approximately the same time that the flow regime decreased in total annual and peak annual flow. Tamarisk, a nonnative shrub, began to establish in the 1930s as well. Narrowing from the 1940s to the mid-1980s was insignificant, because floodplain formation was approximately matched by bank erosion. Air photo analysis demonstrates that the most significant episode of narrowing was underway by the late 1980s, and analysis of the trench shows that floodplain formation had begun in the mid-1980s during a multi-year period of low peak annual flow. Air photo analysis shows that mean channel width decreased by ∼7% between 1993 and 2009. A new phase of narrowing may have begun in 2003, based on evidence in the trench. Comparison of field surveys made in 1998 and 2015 in an 8.5 km reach near Fort Bottom suggests that narrowing continues and demonstrates that new floodplain formation has been a very small proportion of the total annual fine sediment flux of the Green River. Vertical accretion of new floodplains near Fort Bottom averaged 2.4 m between 1998 and 2015 but only accounted for ∼1.5% of the estimated fine sediment flux during that period. Flood control by Flaming Gorge Dam after 1962 significantly influenced flow regime, reducing the magnitude of the annual snowmelt flood and increasing the magnitude of base flows. Though narrowing was initiated by changes in flow regime, native and nonnative riparian vegetation promoted floodplain formation and channel narrowing especially through establishment on channel bars and incipient floodplains during years of small annual floods.

Download Full-text