scholarly journals Effect of soil properties on peat erosion and suspended sediment delivery in drained peatlands

2014 ◽  
Vol 50 (4) ◽  
pp. 3523-3535 ◽  
Author(s):  
Tapio Tuukkanen ◽  
Hannu Marttila ◽  
Bjørn Kløve
Keyword(s):  
Soil Properties ◽  
Suspended Sediment ◽  
Sediment Delivery

Hydrometeorological assessments and suspended sediment delivery from a central Himalayan glacier in the upper Ganga basin

2018 ◽  
Vol 33 (4) ◽  
pp. 493-509 ◽  
Author(s):  
Amit Kumar ◽  
Akshaya Verma ◽  
Anupam Anand Gokhale ◽  
Rakesh Bhambri ◽  
Anshuman Misra ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Delivery ◽  
Ganga Basin ◽  
Himalayan Glacier

Revised sediment transport model for estimation of suspended sediment flux and chemical composition of the Irrawaddy and Salween rivers

2020 ◽  
Author(s):  
J. Jotautas Baronas ◽  
Edward T. Tipper ◽  
Michael J. Bickle ◽  
Robert G. Hilton ◽  
Emily I. Stevenson ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Carbon ◽  
Suspended Sediment ◽  
Transport Model ◽  
Sediment Concentration ◽  
Sediment Flux ◽  
Sediment Discharge ◽  
Anthropogenic Pressures ◽  
Modeling Framework ◽  
Sediment Delivery

<p>A large portion of freshwater and sediment is exported to the ocean by just several of the world's major rivers. Many of these mega-rivers are under significant anthropogenic pressures, such as damming and sand mining, which are having a significant impact on water and sediment delivery to deltaic ecosystems. However, accurately measuring the total sediment flux and its mean physicochemical composition is difficult in large rivers due to hydrodynamic sorting of sediments. To account for this, we developed an updated semi-empirical Rouse modeling framework, which synoptically predicts sediment concentration, grain size distribution, and mean chemical composition (organic carbon wt%, Al/Si ratio) with depth and across the river channel.</p><p>We applied this model to derive new sediment flux estimates for the Irrawaddy and the Salween, the last two free-flowing mega-rivers in Southeast Asia, using a newly collected set of suspended sediment depth samples, coupled to ADCP-measured flow velocity data. Constructing sediment-discharge rating curves, we calculated an annual sediment flux of 326 (68% confidence interval of 256-417) Mt/yr for the Irrawaddy and 159 (109-237) Mt/yr for the Salween, together accounting for 2-3% of total global riverine sediment discharge. The mean flux-weighted sediment exported by the Irrawaddy is significantly coarser (D<sub>84</sub> = 193 ± 13 µm) and OC-poorer (0.29 ± 0.08 wt%) compared to the Salween (112 ± 27 µm and 0.59 ± 0.16 wt%, respectively). Both rivers export similar amounts of particulate organic carbon, with a total of 1.9 (1.0-3.3) Mt C/yr, contributing ~1% of the total riverine POC export to the ocean. These results underline the global significance of the Irrawaddy and Salween rivers and warrant continued monitoring of their sediment fluxes, given the increasing anthropogenic pressures on these river basins.</p>

scholarly journals Interactions between aquatic vegetation, hydraulics and fine sediment

2020 ◽  
Author(s):  
Hamish Biggs ◽  
Arman Haddadchi ◽  
Murray Hicks
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Hydraulic Resistance ◽  
Vegetation Cover ◽  
Aquatic Vegetation ◽  
Fine Sediment ◽  
Suspended Sediment Transport ◽  
Sediment Delivery ◽  
Lowland Streams ◽  
Mechanical Removal

Aquatic vegetation, hydraulics and sediment transport have complex interactions that are not yet well understood. These interactions are important for sediment conveyance, sediment sequestration, phasing of sediment delivery from runoff events, and management of ecosystem health in lowland streams. To address this knowledge gap detailed field measurements of sediment transport through natural flexible aquatic vegetation are required to supplement and validate laboratory results. This paper contributes a field study of suspended sediment transport through aquatic vegetation and includes mechanical removal of aquatic vegetation with a weed cutting boat. It also provides methods to quantify vegetation cover through remote sensing with Unmanned Aerial Vehicles (UAVs) and estimate biomass from ground truth sampling. Suspended sediment concentrations were highly dependent on aquatic vegetation abundance, and the distance upstream that had been cleared of aquatic vegetation. When the study reach was fully vegetated (i.e. cover >80%), the maximum recorded SSC was 14.6 g/m (during a fresh with discharge of 2.47 m/s), during weed cutting operations SSC was 76.8 g/m at 0.84 m/s (weedcutting boat 0.5-1 km upstream from study reach), however following weed cutting operations (4.6 km cleared upstream), SSC was 139.0 g/m at a discharge of 1.52 m/s. The data indicates that fine sediment was being sequestered by aquatic vegetation and likely remobilised after vegetation removal. Investigation of suspended sediment spatial dynamics illustrated changes in particle size distribution due to preferential settling of coarse particles within aquatic vegetation. Hydraulic resistance in the study reach (parameterized by Manning’s n) dropped by over 70% following vegetation cutting. Prior to cutting hydraulic resistance was discharge dependent, while post cutting hydraulic resistance was approximately invariant of discharge. Aerial surveying captured interesting changes in aquatic vegetation cover, where some very dense regions of aquatic vegetation were naturally removed leaving behind unvegetated riverbed and fine sediment.

scholarly journals Interactions between fine-grained sediment delivery, river bed deposition and salmonid spawning success

2015 ◽  
Vol 367 ◽  
pp. 199-206 ◽  
Author(s):  
I. Pattison ◽  
D. A. Sear ◽  
A. L. Collins ◽  
J. I. Jones ◽  
P. S. Naden
Keyword(s):  
Suspended Sediment ◽  
Discrete Event ◽  
Survival Rates ◽  
Fine Sediment ◽  
Egg Survival ◽  
Egg Development ◽  
Sediment Delivery ◽  
Modelling Framework ◽  
River Bed ◽  
The Impact

Abstract. Salmonids clean river bed gravels to lay their eggs. However, during the incubation period fine sediment infiltrates the bed. This has been found to limit the success of salmonid spawning, as fine sediment reduces gravel permeability resulting in intra-gravel flow velocities and O2 concentrations decreasing. The success of salmonid spawning is therefore a function of the coincidence of fine sediment delivery and the development of the salmonid eggs. The presence of fine sediment also exerts sub-lethal effects on the rate of egg development with a negative feedback slowing and extending the incubation process meaning the eggs are in the gravels for longer and susceptible to more potential sediment delivery events. The SIDO (Sediment Intrusion and Dissolved Oxygen)-UK model is a physically-based numerical model which simulates the effect of fine sediment deposition on the abiotic characteristics of the salmonid redd, along with the consequences for egg development and survival. This model is used to investigate the interactions and feedbacks between the timing and concentrations of suspended sediment delivery events, and the deposition of fine sediment within the gravel bed, and the consequences of this on the rate of egg development and survival. The model simulations suggest that egg survival is highly sensitive to suspended sediment concentrations, particularly to changes in the supply rate of sand particles. The magnitude, frequency and specific timing of sediment delivery events effects egg survival rates. The modelling framework is also used to investigate the impact of the rate of gravel infilling by sediment. The hypotheses of continual, discrete event and non-linear decline in the rate of infilling are investigated.

Documenting catchment suspended sediment sources: problems, approaches and prospects

2004 ◽  
Vol 28 (2) ◽  
pp. 159-196 ◽  
Author(s):  
A. L. Collins ◽  
D. E. Walling
Keyword(s):  
Suspended Sediment ◽  
Direct Approach ◽  
Sediment Sources ◽  
Catchment Scale ◽  
Sediment Delivery ◽  
Validation Data ◽  
Distributed Approach ◽  
Sediment Routing ◽  
Alternative Means ◽  
Sediment Mobilization

Establishing catchment suspended sediment sources is fraught with difficulty. Data collection comprises indirect and direct approaches and an overview is provided. The indirect approach uses a range of techniques to measure or evaluate sediment mobilization. Yet, although recent technological advances in surveying, remote sensing and photogrammetry provide improved resolution of temporal and spatial patterns of catchment erosion, these procedures take no account of source-river connectivity and the uncertainties associated with sediment routing. It is therefore only possible to infer the provenance of suspended sediment loads on the exclusive basis of on-site erosion data for different portions of the upstream catchment unless supportive information on sediment delivery is readily available. In contrast, the direct approach attempts to link sediment sources and flux using alternative means and therefore avoids the need for complementary information. Sediment fingerprinting best represents the direct approach to sediment sourcing and there remains substantial scope for exploiting the potential of this technique. The spatial complexity of sediment mobilization and transfer at the catchment scale necessitates a distributed approach to modelling. Recent developments in computer power and programming techniques are proving useful in this respect, but assembling the input and validation data required by distributed models continues to pose problems and it is frequently difficult to apportion the relative contributions from individual sediment sources. General prospects for future developments are discussed.

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