scholarly journals Modelling of sedimentation processes inside Roseires Reservoir (Sudan)

2015 ◽  
Vol 3 (2) ◽  
pp. 223-238 ◽  
Author(s):  
A. Y. A. Omer ◽  
Y. S. A. Ali ◽  
J. A. Roelvink ◽  
A. Dastgheib ◽  
P. Paron ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Deposition Time ◽  
Storage Capacity ◽  
Nile River ◽  
Field Campaign ◽  
River Catchment ◽  
Bathymetric Data ◽  
Sediment Deposits ◽  
Sediment Stratification ◽  
Sedimentation Processes

Abstract. Roseires Reservoir, located on the Blue Nile River in Sudan, is the first trap to the sediments coming from the vast upper river catchment in Ethiopia, which suffers from high erosion and desertification problems. The reservoir has already lost more than one-third of its storage capacity due to sedimentation in the last four decades. Appropriate management of the eroded soils in the upper basin could mitigate this problem. In order to do that, the areas providing the highest sediment volumes to the river have to be identified, since they should have priority with respect to the application of erosion control practices. This requires studying the sedimentation record inside Roseires Reservoir in order to assess when and how much sediment is deposited and to identify its source. This paper deals with the identification of deposition time and soil stratification inside the reservoir, based on historical bathymetric data, numerical modelling and newly acquired soil data. The remoteness of the study area and the extreme climate result in coring campaigns being expensive and difficult. Therefore, these activities need to be optimised and coring locations selected beforehand. This was done by combining bathymetric data and the results of a depth-averaged morphodynamic model recording the vertical stratification in sediment deposits. The model allowed for recognising the areas that are potentially subject to neither net erosion nor bar migration during the lifespan of the reservoir. Verification of these results was carried out by analysing sediment stratification from the data collected during the subsequent field campaign.

scholarly journals Modelling of sedimentation processes inside Roseires Reservoir (Sudan)

2014 ◽  
Vol 2 (1) ◽  
pp. 153-179 ◽  
Author(s):  
A. Y. A. Omer ◽  
Y. S. A. Ali ◽  
J. A. Roelvink ◽  
A. Dastgheib ◽  
P. Paron ◽  
...  
Keyword(s):  
Life Span ◽  
Deposition Time ◽  
Storage Capacity ◽  
Nile River ◽  
Field Campaign ◽  
Blue Nile ◽  
Bathymetric Data ◽  
Sediment Deposits ◽  
Sediment Stratification ◽  
Sedimentation Processes

Abstract. Roseires Reservoir, located on the Blue Nile River, in Sudan, is the first trap to the sediments coming from the upper catchment in Ethiopia, which suffers from high erosion and desertification problems. The reservoir lost already more than one third of its storage capacity due to sedimentation in the last four decades. Appropriate management of the eroded area in the upper basin could mitigate this problem. In order to do that, the areas providing the highest sediment volumes to the river have to be identified, since they should have priority with respect to the application of erosion control practices. This requires studying the sedimentation record inside Roseires Reservoir, with the aim of identifying when and how much sediment from a certain area is deposited. The identification of deposition time is derived from soil stratification inside the reservoir. This requires expensive coring campaigns that need to be optimized. The most promising sampling coring areas were therefore selected beforehand by combining bathymetric data and the results of a depth-averaged morphodynamic model able to record vertical stratification in sediment deposits. The model allowed recognising the areas that are potentially neither subject to net erosion nor to bar migration during the life span of the reservoir. Verification of these results was carried out by analysing sediment stratification from the data collected in subsequent field campaign.

Principles and approaches for numerical modelling of sediment transport in sewers

1995 ◽  
Vol 31 (7) ◽  
pp. 107-115 ◽  
Author(s):  
Ole Mark ◽  
Cecilia Appelgren ◽  
Torben Larsen
Keyword(s):  
Mathematical Model ◽  
Sediment Transport ◽  
Numerical Modelling ◽  
Simple Application ◽  
Sewer Systems ◽  
Sediment Deposits ◽  
Model Mouse ◽  
Modelling Approaches

A study has been carried out with the objectives of describing the effect of sediment deposits on the hydraulic capacity of sewer systems and to investigate the sediment transport in sewer systems. A result of the study is a mathematical model MOUSE ST which describes sediment transport in sewers. This paper discusses the applicability and the limitations of various modelling approaches and sediment transport formulations in MOUSE ST. Further, the paper presents a simple application of MOUSE ST to the Rya catchment in Gothenburg, Sweden.

scholarly journals A Prior Estimation of the Spatial Distribution Parameter of Soil Moisture Storage Capacity Using Satellite-Based Root-Zone Soil Moisture Data

2019 ◽  
Vol 11 (21) ◽  
pp. 2580 ◽  
Author(s):  
Yifei Tian ◽  
Lihua Xiong ◽  
Bin Xiong ◽  
Ruodan Zhuang
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Storage Capacity ◽  
Spatial Information ◽  
Root Zone ◽  
River Catchment ◽  
Soil Moisture Storage ◽  
Soil Moisture Data ◽  
Moisture Storage ◽  
The Impact

Integration of satellite-based data with hydrological modelling was generally conducted via data assimilation or model calibration, and both approaches can enhance streamflow predictions. In this study, we assessed the feasibility of another approach that uses satellite-based soil moisture data to directly estimate the parameter β to represent the degree of the spatial distribution of soil moisture storage capacity in the semi-distributed Hymod model. The impact of using historical root-zone soil moisture data from the Soil Moisture Active Passive (SMAP) mission on the prior estimation of the parameter β was explored. Two different ways to incorporate the root-zone soil moisture data to estimate the parameter β are proposed, i.e., one is to derive a priori distribution of β , and the other is to derive a fixed value for β . The simulations of the Hymod models employing the two ways to estimate β are compared with the results produced by the original model, i.e., the one without employing satellite-based data to estimate the parameter β , at three study catchments (the Upper Hanjiang River catchment, the Xiangjiang River catchment, and the Ganjiang River catchment). The results illustrate that the two ways to incorporate the SMAP root-zone soil moisture data in order to predetermine the parameter β of the semi-distributed Hymod model both perform well in simulating streamflow during the calibration period, and a slight improvement was found during the validation period. Notably, deriving a fixed β value from satellite soil moisture data can provide better performance for ungauged catchments despite reducing the model freedom degrees due to fixing the β value. It is concluded that the robustness of the Hymod model in predicting the streamflow can be improved when the spatial information of satellite-based soil moisture data is utilized to estimate the parameter β .

Application of Numerical Modelling for the Prediction of Sediment Deposits after Sejong Weir Installation

2015 ◽  
Vol 15 (4) ◽  
pp. 243-249
Author(s):  
Hayong Kim ◽  
Jihong Park ◽  
Woncheol Park ◽  
Ilpyo Hong ◽  
Sangman Jeong
Keyword(s):  
Numerical Modelling ◽  
Sediment Deposits

Submesoscale physical processes in the atmospheric boundary layer above fragmented sea ice.

2020 ◽  
Author(s):  
Marta Wenta ◽  
Agnieszka Herman
Keyword(s):  
Boundary Layer ◽  
Numerical Modelling ◽  
Sea Ice ◽  
Atmospheric Boundary Layer ◽  
Weather Prediction ◽  
Heat Fluxes ◽  
Physical Processes ◽  
Sea Ice Extent ◽  
Field Campaign ◽  
Modelling Studies

<p>In consequence of sea ice fragmentation in winter a range of physical processes take place between the sea/sea ice and the atmospheric boundary layer (ABL). Most of them occur on the level of individual ice floes and cracks and thus cannot be directly resolved by numerical weather prediction (NWP) models.  Parametrizations of those processes aim to describe their overall effect on grid scale values, given the grid scale variables. However, as many of the processes taking place during winter sea ice fragmentation remain largely unrecognized they cannot be incorporated into the NWP models. </p><p>The aim of the presented study is to determine whether the floe size distribution (FSD) has an effect on the ABL. Our previous research (Wenta, Herman 2018 and 2019) indicates that FSD might determine the intensity and spatial arrangement of convection and heat fluxes. A coefficient has been proposed for the correction of moisture heat flux, which can be incorporated into the NWP models. However, this research is based entirely on idealized model simulations and requires further modelling and observations based studies.</p><p>In order to address this shortcoming, a field campaign is going to take place in the Bay of Bothnia in March 2020. Our goal is to create a 3D view of the atmosphere above fragmented sea and verify whether the processes and effects we found in the modeling results take similar form in real situations. Measurements results will be useful in the validation of our numerical modelling studies and will provide a unique dataset about the sea-ice-atmosphere interactions in the Bay of Bothnia area. Considering a significant decreasing trend in winter sea ice extent in the Baltic Sea it might contribute to our understanding of the role of ice in the local weather patterns. The field campaign is going to be complemented by numerical modelling with full version of Weather Research and Forecasting (WRF) model adjusted to the conditions over the Bay of Bothnia. </p><p>Combined together - the results of our previous modelling studies and the results from the Bay of Bothnia field campaign, may considerably increase our knowledge about the surface-atmosphere coupling in the event of winter sea ice fragmentation.</p>

scholarly journals Toward an operational approach for the characterization and modelling of fine sediments dynamics in reservoirs

2018 ◽  
Vol 40 ◽  
pp. 03028
Author(s):  
Christophe Peteuil ◽  
Magali Jodeau ◽  
Matthieu De Linares ◽  
Eric Valette ◽  
Damien Alliau ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Management Strategies ◽  
Field Method ◽  
Sediment Dynamics ◽  
Essential Requirement ◽  
Fine Sediments ◽  
Lab Experiments ◽  
Sediment Deposits ◽  
Dynamics Modelling

Achieving a sustainable management of sediment fluxes in existing or proposed reservoirs is a challenging but essential requirement for dam operators. Such objective is of utmost importance to avoid sedimentation-related consequences. Numerical modelling is of great interest to understand the flow and sediment dynamics in a reservoir, to simulate the long-term evolution of sediment deposits and to evaluate the efficiency of various management strategies. This paper presents recent case studies, which validate the feasibility and relevancy of such technical option. The progresses obtained on essential stages of the numerical modelling of sediments dynamics in reservoirs are particularly emphasized. Concerning the distribution of deposits, a promising field method based on an optimum combination of direct samplings with acoustic measurements and video auscultations is detailed. Feedbacks are then provided concerning an innovative device deployed in the field for a direct measurement of the settling velocity. Issues about the assessment of calibration parameters are also addressed in this communication. Lab experiments performed on deposits sampled in several reservoirs provide practical guidance to evaluate the erosion parameters of sediments. Finally, several examples of sediment dynamics modelling in reservoirs including both cohesive and non-cohesive sediment are presented.

Multi-century tree-ring precipitation record reveals increasing frequency of extreme dry events in the upper Blue Nile River catchment

2017 ◽  
Vol 23 (12) ◽  
pp. 5436-5454 ◽  
Author(s):  
Mulugeta Mokria ◽  
Aster Gebrekirstos ◽  
Abrham Abiyu ◽  
Meine Van Noordwijk ◽  
Achim Bräuning
Keyword(s):  
Tree Ring ◽  
Nile River ◽  
Blue Nile ◽  
River Catchment ◽  
Precipitation Record

Combining analytical and numerical modelling of gas flow in depleted natural gas fields to identify potential Underground Hydrogen Storage (UHS) sites in the Netherlands 

2021 ◽  
Author(s):  
Joaquim Juez-Larre ◽  
Cintia Gonçalves Machado ◽  
Hamid Yousefi ◽  
Remco Groenenberg
Keyword(s):  
Natural Gas ◽  
The Netherlands ◽  
Numerical Modelling ◽  
Hydrogen Storage ◽  
Storage Capacity ◽  
Winter Season ◽  
Energy System ◽  
Potential Candidate ◽  
Gas Fields ◽  
Underground Reservoirs

<p>The Netherlands is seeking ways to integrate large amounts of renewable energy production capacity (wind/solar) into its energy system, in order to reduce CO<sub>2</sub> emissions and decrease dependency on future energy imports. Currently the Netherlands uses underground gas storage (UGS) to provide flexibility to its natural gas system, and secure supply during the winter season. However, hydrogen is considered to be a potential candidate to substitute natural gas, because it is a versatile energy carrier that can be produced from renewable electricity and be used as a CO<sub>2</sub>-neutral fuel and feedstock. It can also be stored in large amounts underground. Storage of compressed hydrogen in salt caverns is a proven technology, with single-cavern storage capacities in the range of 10-100 million m<sup>3</sup>. Yet some studies on the future Dutch energy system suggest much larger volumes of hydrogen storage may be required (1 to 50 billion m<sup>3</sup>). This large storage capacity can only be practically achieved in depleted natural gas fields. UHS in gas fields is not yet a proven technology. Only some pilot projects have successfully injected small amounts of hydrogen in some available underground reservoirs. In order to make possible future development of UHS, screening methodologies are needed for the readily identification and characterization of potential underground candidates. In this study, we develop a methodology that allows assessing UHS performances of large portfolios of underground reservoirs. As a case study we use the entire portfolio of natural gas fields in the Netherlands, including three UGSs.</p><p>In a first stage of our study, we conducted a nodal analysis of the Inflow Performance Relationship (IPR) and the vertical flow performance (outflow) curves, in order to obtain a first order estimate of the potential UHS performance for each field (e.g. rates of injection/withdrawal, working/cushion gas volumes and ranges of working pressures). Results show that withdrawal performances of wells in an UHS can be 2-3 times higher than those in an UGS. High bottom-hole drawdowns and erosional velocities in the production tubing may however significantly restrict the potential flow of hydrogen. Furthermore, the working gas volume of an UHS may contain up to four times less energy than that of an UGS, if operated at the same ranges of working pressures. Secondly, we used Eclipse 300, and the geological Petrel model of some of the best candidates, to conduct a more detail analysis of their potential UHS performances and the controlling factors. For that we ran consecutive injection/withdrawal cycles at different timescales (daily-weekly-monthly), and distinct working pressure ranges and types of cushion gas (e.g. nitrogen/hydrogen). Results allow to determine the efficiency of the different operational strategies and the number of wells required to match the expected future demands of hydrogen in the Netherlands. They also show the degree of hydrogen mixing with the residual and cushion gas during each cycle. Therefore our analytical/numerical modelling approach provides a good methodology to quantify and rank potential UHS reservoir candidates, and a means to classify the potential storage capacity of the entire portfolio.</p>

scholarly journals Assesment of bathymetric maps via GIS for water in reservoir

2014 ◽  
Vol 20 (1) ◽  
pp. 142-158 ◽  
Author(s):  
Ayhan Ceylan ◽  
Ilke Ekizoglu
Keyword(s):  
Information System ◽  
Storage Capacity ◽  
Plant Cover ◽  
Geological Structure ◽  
Bathymetric Data ◽  
Efficient Management ◽  
Digital Elevation ◽  
Wide Range ◽  
Average Water ◽  
Area Data

In order to adopt measures for storing more water in reservoirs, lakes and ponds; to prevent water pollution, protect water sources and extend the service life of these facilities, it is important for manager (Municipalities, Directorates of the State Hydraulic Works (DSHW), Irrigation Unions etc.) to know the current topographic conditions and any changes in the storage capacities of these facilities. This study aimed to identify the updated topographic and bathymetric data required for the efficient management and usage of Altınapa reservoir, changes in surface area and volume of the facility, and to form a Reservoir Information System (RIS). Two digital elevation models, from 2009 and 1984, were used to determine changes in the storage capacity of the reservoir. The calculations indicated that, within this 25-year period, the storage capacity of the reservoir decreased by 12.7% due to sedimentation. A Dam Information System (RIS) was developed from a wide range of data sources, including topographic and bathymetric data of the reservoir and its surrounding area, data on specific features such as plant cover, water quality characteristics (Temperature, Dissolved Oxygen (DO), Secchi Disk Depth (SDD) and pH), geological structure, average water level, water supplied from springs, evaporation value of the reservoir, and precipitation.

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