Evaluation of Sediment Management Strategies on Reservoir Storage Depletion Rate: A Case Study (original) (raw)
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Applied Water Science
Globally the average annual loss of reservoir capacity is approximately 1%. Pakistan is confronting major issue of sedimentation which is continuously depleting the useful storage of reservoirs. GSTARS3 model was used to determine the rate of deposition and sediment pattern of Chashma Reservoir since its operation. The model was calibrated and validated for bathymetric survey of 2008 and 2012. The results of GSTARS3 were incorporated to a GIS software to visualize sediment accumulation in reservoir. The study reveals that sediment flushing of the Chashma Reservoir can be carried out during flood season at a pond level of 638.15 ft. (194.51 m). However, its negative impact if any on the hydropower generation needs to be analysed. Accordingly, modified operation rules would be required.
Evaluation Of Sediment Management Strategies For Large Reservoirs
Research Square (Research Square), 2021
Multipurpose large dams play a key role in the development of world by providing water for irrigation, ood control and hydropower. Tarbela is one of the world's largest earth and rock ll dam. Being multipurpose dam, it provides vital role for economic stability and social development of Pakistan. Tarbela Reservoir has lost its signi cant capacity due to sediment deposition. The objective of the study was to evaluate different options for evacuation of deposited sediments and reducing sediment in ows to Tarbela Reservoir through sediment modeling by HEC-RAS. Sediment ushing from existing power tunnels was evaluated in rst option and found not feasible due to the downstream constraints and loss of 7848 MW hydropower from Tarbela and Ghazi Barotha. New sediment bypass tunnels were proposed on right bank of the dam to overcome the constraints in second option. Sediment modeling was performed by HEC-RAS to evaluate each scenario of sediment ushing with different parameters. The sediment balance ratio and long term capacity ratio was also checked for each scenario for technical evaluation and also economic analysis was performed. Most technical viable scenario was ushing for 90 days at reservoir drawdown level of 390 m with discharge of 5000m 3 /s. However, this scenario was not economically feasible as net present value was negative, internal rate of return was 3-4 %, and bene t cost ratio was found less than one. The 3 rd option, with under construction multipurpose Diamer Basha Dam on upstream of Tarbela Reservoir, was also evaluated on HEC-RAS. Results depicted that large amount of sediments were trapped in the upstream reservoir which ultimately reduced signi cantly the in ow of sediments and delta movement in Tarbela Reservoir. This option is recommended because it will enhance the life of Tarbela Reservoir and it will keep on providing multiple bene ts for longer time.
Zenodo (CERN European Organization for Nuclear Research), 2022
Sengguruh and Sutami Reservoir are facing severe sedimentation problems, that causes a significant decrease in storage capacity. Sengguruh Reservoir leaves ± 5.85% of the initial capacity, while the Sutami Reservoir only leaves ± 51.94% of the initial capacity which affects the capacity of energy generation, fulfillment of irrigation water, raw water and flood control. Erosion and sedimentation analysis was carried out using the USLE method to determine sedimentation potential based on 2019 land use, reservoir storage capacity analysis using bathymetry results to determine sedimentation rates and prediction of reservoir life, and sediment balance analysis to determine appropriate sediment management efforts. Integrated sediment management from upstream to downstream (reservoir) is a solution. Watershed conservation is the most important effort in sediment management, because watershed conservation can reduce sedimentation potential by 3,16%. Management and construction of sediment control structures on the Brantas River and Lesti River as well as construction of retaining structures and waste processing at the settlement pond location upstream of the Sengguruh Reservoir can reduce reservoir sedimentation by 6.95%. Sediment dredging of 250,000 m 3 /yr for Sengguruh Reservoir and flushing every 3 (three) years can increase the storage capacity by 9.45%. Meanwhile, in Sutami Reservoir, through dredging efforts of at least 400,000 m 3 /yr, can maintain the function of the reservoir for the next 135 years.
Predictings Sediment Loading into Masinga Reservoir and its Storage Capacity Reduction
boku.ac.at
It is estimated that the annual loss in storage capacity of the world's reservoirs due to sedimentation is around 0.5 -1.0%. For many reservoirs, however, annual depletion rates are much higher and can go up to 4% or 5%, such that they lose the majority of their capacity after only 25 -30 years. The Masinga reservoir, one of the main reservoirs in Kenya, designed for hydropower generation, public water supply and irrigation is faced with severe sedimentation. The designed sediment load into this reservoir in 1981 was estimated to be 3.0 x 10 6 m 3 per year (about 1% per annum reservoir reduction). By 2000, annual sediment loading had increased to over 11.0 x 10 6 m 3 , nearly four times, thus reducing the designed capacity by more than 15%. As land degradation has become more evident with increasing land use change within Masinga catchment over the years, the operation and life span of Masinga reservoir is thus under imminent danger from erosion and sedimentation. There is need therefore to quantify spatially soil erosion and sediment yield reaching the reservoir with a view to reducing the sediment delivery. In this paper, a comprehensive procedure to predict spatial sediment yield and overall mean annual sediment volume delivered to Masinga reservoir is presented. Geographical Information System (GIS) technology as a tool to support soil erosion and sediment models is employed. Simulations of different land use and management scenarios are performed and their corresponding sediment yields estimated. Predictions show annual sediment loading into the reservoir of about 14.0 x 10 6 m 3 for land use practices in 2003. By simulating the best feasible management practices (BMPs), the achieved results show that the sediment volume reaching the reservoir could be reduced to about 6.0 x 10 6 m 3 per year.
Purakala (UGC Care Journal), 2020
Every Reservoir is prone to certain problems that affect its functionality and lifespan including stresses, seismic actions, floods etc., But, Life of reservoir is momentously depended on the sediment occurring in the reservoir. Assessing the quantity of sediment and implementing remedial measures will greatly help to sustain storage capacity of reservoir. This study deals with finding varies sediment deposited annually in Sri ram Sagar Project, using Arc GIS 10.4 by plugin called Arc SWAT (Soil and Water Analysis Tool). The obtained results are compared to validated from Godavari sediment year book (15-16) from Central Water Commission and SWAT analysis was found to give appropriate sediment Deposit Edition. Further, the useful life of reservoir is numerically calculated and compared with useful life obtained from Gill equation and was found satisfactory. Finally,the analysis of variance for a change in sediment deposited and inflow and runoff to analyze fully and appropriately is done using Anova and the results are inferred.
Sediment distribution and its impacts on Hirakud Reservoir (India) storage capacity
Lakes & Reservoirs: Science, Policy and Management for Sustainable Use, 2016
Construction of dams causes reduced flow velocities, inducing gradual deposition of sediments carried by the inflowing stream, and resulting in sedimentation and ultimately diminishing reservoir storage capacity. This study focuses on sedimentation of Hirakud Reservoir in Odisha, India, using available reservoir capacity and numerical simulation data. Reduced trap efficiency, observed and projected capacity curves, rising reservoir bed level and the capacities of the different storage zones for various projected years are analysed. The area-reduction method indicates the loss in the live, gross and dead storage will be 58%, 63% and 100%, respectively, of their original capacities by 2057, which represents 100 years of impounding of water in the reservoir. If the present sediment inflow rate continues without regular flushing of the deposited sediment, it is predicted the reservoir bed level will rise to the full reservoir level of 192.02 m by the year 2110. Brune's trap efficiency and step method indicate the gross storage zone of Hirakud Reservoir will be completely depleted by the end of 2110, with the trap efficiency reduced to zero. The empirical area-reduction method is found to be more suitable for determining the storage capacities of Hirakud Reservoir in the absence of sedimentation survey data. An attempt was also made to solve the combined hydrodynamic and sediment transport equations numerically to predict morphological changes in Hirakud Reservoir. The finite-element code TELEMAC-2D and finite-volume code for SISYPHE, respectively, were applied to solve the above set of equations in order to predict the bed profiles at different reservoir cross sections for the period of 1958-2008. Analysis of the simulated results demonstrates that, considering the model inputs, the model performs well in simulating the morphology and dynamic characteristics of a reservoir. Projection of the numerical results indicates a complete loss of reservoir operational life due to sedimentation by around 2150.
Sedimentation Problem in Khassa Chai Reservoir and Methods of Combat
Tikrit University College of Engineering Civil Engineering Department , 2014
Reservoir sedimentation is one of the severe problems which faces dams as sediments occupy spaces within reservoirs storage, hence, decreasing live water storage which is the main purpose of dams construction. Iraq is one of the countries that will face significant shortage in water income as a result of both the increment in water demand and of the reduction of water shares from the source countries. Thus, the existing dams in the Iraq represent a strategic resource to fulfil water demands, and the sedimentation at these dams are studied to assess the quantity of sediments that reach to these reservoirs and decrease available water volume and useful life of reservoir. In the current study, Khassa Chai Dam, which is still under construction, located in the north east of Iraq and its main watershed basin covers an area of about 412 km2 between Kirkuk and Al Sulaymaniyah governorates has been selected to estimate and predict the amount of sediment yield based on 30 years of daily climate data and the events of different intensity rainstorms. AGWA (Automated Geospatial Watershed Assessment tool) model has been used to simulate Khassa Chai Dam catchment area. This model utilizes the GIS (Geographic Information System) application to analyse the required data from GIS layer for DEM (Digital Elevation Model), Soil type, Land use and Land cover by interference with the required climate data. The results of this study identified the amount of sediment yield and water inflow to the reservoir. They also identified the sub watersheds which have high affinity for soil erosion, sediment yield, and delivery ratio within the main catchment area watershed manage these sub watersheds by applying certain techniques and methods which may decrease the sediment yield that reaches to the reservoir.
Sedimentation Processes and Useful Life of Mosul Dam Reservoir, Iraq
Engineering, 2013
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Life forecasting of Getalsud Reservoir in India based on its sedimentation behaviour
Lakes & Reservoirs: Science, Policy and Management for Sustainable Use, 2011
The sedimentation behaviour of Getalsud Reservoir in the Jharkhand State of India was studied, and its useful life and performance forecasted. The quantity of sediment and its vertical distribution over different reservoir elevations have been estimated using standard methods. The study results indicate the provisions made for sediment deposit in the reservoir are sufficient, and the useful life of the reservoir will be longer than its design life of 100 years. The trap-efficiency of the reservoir is not anticipated to vary much until the year 2250, after which it is expected to rapidly decrease. In the first 100 years of impoundment, the reservoir loses 60% of its dead storage, 13% of its live storage and 24% of its gross storage. At its present sedimentation rate, Getalsud Reservoir may become fully obsolete by the year 2500.
International Journal of Engineering and Applied Sciences (IJEAS), 2020
Reservoir sedimentation is one of the main challenges faced by storage hydroelectric projects all over the world. Particularly for a country like Nepal which lies in the center of "Himalaya Arc", a region with one of the highest sediment yields in the world, reservoir sedimentation can be one of the biggest issues for storage type projects. It may result in the loss of huge capital investment and revenues. Thus to minimize the reservoir sedimentation problem and to ensure the sustainability of the existing as well as upcoming future storage projects, timely measures for sediment management strategy are required. RESCON 2 model sponsored by Word Bank is the tool for the rapid assessment of sustainable sediment management strategies. The model is based on the Life Cycle Management approach which focuses on managing the reservoir by economical and technical evaluation of different sediment management alternatives to extend the life of the reservoir for an almost indefinite lifetime. Thus this study is carried out for the assessment of sustainable sediment management technique for proposed Budhi Gandaki Hydroelectric project (BGHEP) using the RESCON 2 model. One of the important parameters for the assessment of sustainable sediment strategies is specific sediment yield. So in this study 9 sediment management techniques incorporated in RESCON 2 model have been evaluated based on two specific sediment yield, 1) estimated from BQART empirical method, 2) data from the BGHEP study report. From the calculation it was found that the BQART model overestimated the sediment yield than presented in BGHEP report and the result indicated Sluicing as the best sediment management technique for both the cases having the highest Aggregate net present value. From sensitivity analysis, Aggregate Net present value and reservoir capacity were found sensitive to unit benefit of reservoir yield, coefficient of variation and annual runoff.