Evaluating Sediment handling strategies for Banja Reservoir using the RESCON2 model - A comprehensive study of the rapid assessment tool for sustainable sediment management
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Banja Reservoir along Devoll River basin, Albania is in threat of loss in storage due to sedimentation. Catchment of Devoll river draining into Banja reservoir has prominent sheet erosion and mass wasting due to intense rainfall and weak geology. This has resulted in higher sediment yield measured along the river. To ensure sustainable operation of Banja reservoir, timely measures for sediment management is necessary.The purpose of this study is to evaluate sediment handling strategies for Banja Reservoir using RESCON2 model, which is a rapid assessment tool for sustainable sediment management strategies in terms of their technical feasibility and economic viability to the project either new or existing. Contrary to contemporary practice of adopting design life philosophy in planning reservoir, RESCON2 incorporates life-cycle management approach that would facilitate the sustainable development of dams and reservoirs. RESCON2 at prefeasibility level can be useful tool to the planners. However, results from the model depends upon the quality of data available at the conception phase of the project. Sediment load to the reservoir is one of the important input which is generally not available and thus require some estimate. For Banja reservoir, it is planned to run the model in two different stages viz. now (2017) and future (2050) where climate change is expected to change the sediment yield. Thus, RUSLE model has been prepared with climate change data to estimate sediment yield for Banja reservoir.The main finding from RUSLE model is that, there will be decreased sediment yield due to decreased annual precipitation in Devoll catchment. RUSLE made quite optimistic estimate of sediment yield of 2.42 million tonnes /year. With this estimate, RESCON2 applied to Banja in different scenario found dredging in combination with catchment management, flushing, sluicing and by-pass to be the most successful and sustainable management option in terms of physical and economic performance. However, to take care of associated uncertainties with climate in future and sediment yield estimate, sensitivity analysis has been performed to test robustness of the anticipated sustainable sediment management options.