Reservoir Sediment Management: Paradigm for Safety & Sustainability
SANJAY GIRI Seconded to EGIS-Eau (France) by Deltares (The Netherlands) Member of ICOLD, NethCOLD, IAHR
Dams: Traps for Water & Sediment Classification of Reservoirs Based on Trapping Feature Sorting out Reservoir (Average Reservoir Volume - million m3)
- Releases floods; - Traps sediments
Black Hole Reservoir
Transparent Reservoir
(Large Reservoir Volume billion m3)
(Run of the River)
Traps floods and sediments
Kantoush and Sumi (2012)
Transparent to floods and sediment transport (fine and coarse)
Dams: Traps for Water & Sediment
Courtesy: USBR
Reservoir Sedimentation: A Global Concern
100% within 200 to 300 years
Water & Energy Demand Flood Management & Risk Safety Concerns
Reservoir Sedimentation in India More than 5000 large dams (> 15 m) Storage loss in 239 reservoirs in India (Record of CWC, 2015)
Loss of storage ≈ 25.7 billion m3 Water Scarcity!
Reservoir Sedimentation in India State Odisha Himachal Gujarat Karnataka Maharashtra Tamil Nadu Uttarakhand Kerala
No of Reservoirs 4 5 60 11 38 67 7 18
Storage Loss (Mm3) 3379 3183 2364 2012 1767 1396 339 202
Average Storage Loss (%) 16 35 19 10 16 18 19 13
Reservoir Sedimentation: Other Concerns Malfunctioning & Damages US & DS Impacts
• Abrasion of Structures • Erosion of Turbines • Flow Level Rise in Upstream • Bank & Bed Erosion in Downstream • Coastal Erosion (45% of Indian Coast)
Courtesy of Rajawat et al. (2014)
Reservoir Sedimentation: Other Concerns Economic, Social & Environmental
Other Impacts
• • • •
• • • •
Energy Production Agriculture & Aquaculture Ecology & Aquatic Nature Water Supply
Additional Loads Reservoir Operation Flood Control Capacity Safety
Graphic courtesy of American Rivers
Concept of Sustainable Use of Reservoir Design Life Concept Conventional Approach
Sustainability Concept
Design Life Time
Decommissioning
Intervention Sustainable Approach
Design Life Time
Sediment Management
Sustainable & safe Varying benefit Indefinite life time
Planned Reservoirs Sustainable Approach
Consideration of River Morphology Integrated Reservoir Management Strategy with SEDIMENT
Sustainable & safe Long-term benefit Indefinite life time
Sediment Management: Criteria & Actions Criteria
Sediment Management
Safety Efficacy Economic Social & Environmental
Long-Term Sustainability
Volume
Age Constraints
Site Conditions
Recurrent
Quality Severity
Quantification Prioritization
Morphology
Process Assessment
Non-Structural
Screening Options
Sedimentation Structural
Actions
Social & Environmental
Hazardous
Impact Assessment
Technical
Economic
Feasibility Study
Designing & Implementing Measures Monitoring
Sediment Management: Criteria & Actions Additional Consideration for Planned Reservoirs
Sediment - An Integral Design Component River Engineering & Morphological Facets Innovative Design and Technology
Intake
Sediment Management: Techniques Excavating
Sediment yield reduction Sediment Routing Sediment Removal
Sediment management Basson’s diagram
Conventional Approach
Structural
Sediment check dam
Diversion weir
Recurrent
5 Afforestation
Non-structural
Sediment bypass tunnel - Erosion control structures - Check/sabo dams - Sediment traps and retention basin - Sediment diversion tunnels and channels - Guiding/training Density current venting structures (open levee, vanes, baffles, weirs, dikes etc.) - Dam heigthening
- Sluicing - Flushing - Density current venting Dredging - Sediment replenishment /relocation - Hydraulic dredging/syphoning/slurr y transport Sediment Flushing - Dry excavation/ trucking/landfill Sediment Replenishing
Trucking
- Catchment/land use management - Erosion control (afforestation, vegetation, contour farming) - Optimization of reservoir operation rule/strategy - Sediment modelling - Real-time monitoring
Sediment Management: Impacts Sediment disaster during flushing at Pillur reservoir
Discolored and polluted Periyar after desiltation of Kallarkutty
Sediment Management: Example 2730 dams (>15 m high) in Japan with 23 billion m3 capacity
Sediment management for Miwa dam, Japan (I.E.A. 2006)
Sediment Management: Adaptive Approach No Sediment Handling
Minimizing Impacts
• Water Loss Control & Conservation • Storage Relocation & Improved Operation Raising the height
Structural Modification
• Sluices and Vents • Raising Dams • Decommissioning
Basis for Sustainable Management Safety Concerns
Growing Water and Energy Demands
Basis & Incentive for Concept of Sustainable Reservoirs
Multidiscip linary Knowledge Integration
Technological Progress & Advantages
Improved Understanding & Engineering Skills
Sediment Management: Technology & Knowledge Integrated Approach
• Catchment to Coast • Data-Models Integration • Optimization
• Integrated Software Framework Innovative • Measurement, Monitoring & Surveillance Technologies • Sediment Handling Technology with Environmental & Technical Merits
R&D Applications
• Modelling (Numerical and Physical) • Data/Image Processing & Analyses (Satellite, Terrestrial Laser Scanner) • End-Pipe Solution (Sediment Handling)
Knowledge Base
• River Engineering & Reservoirs • Sediment Transport & Morphology
Sediment Management: Technology & Knowledge A State-of-the-Art Software Framework for Data Models Coupling
Integrating and Optimizing Supply & Demands
Sediment Management: Technology & Knowledge Monitoring, Measurement and Modelling Real-time monitoring of suspended sediment and density current (Taiwan)
Modelling downstream impact of sediment removal at Pillur
Measurement of reservoir bathymetry
Reservoir Sedimentation Concerns under DRIP ďƒź ďƒź ďƒź
Desiltation plan/proposal for 4 reservoirs (in Tamil Nadu and Uttarakhand) Sediment management studies for selected reservoirs in 7 States Preparing Guidelines for Assessing and Managing Reservoir Sedimentation
Sedimentation near intake at Kundah Palam
Sedimentation near intake at Pillur
Sedimentation at Papanasam
Sedimentation at Maneri Bhali I
Thank You!