Successfully reported this slideshow.
Your SlideShare is downloading. ×

DSD-INT 2022 Modelling the impact of dam operation on flood management using D-Flow FM 1D coupled with D-Real Time Control - Yeditha

Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Loading in …3
×

Check these out next

1 of 27 Ad

More Related Content

More from Deltares (20)

Recently uploaded (20)

Advertisement

DSD-INT 2022 Modelling the impact of dam operation on flood management using D-Flow FM 1D coupled with D-Real Time Control - Yeditha

  1. 1. Modelling the impact of dam operation on flood management using D-Flow FM 1D coupled with D-Real Time Control: A case study of Mettur Dam in Cauvery River (India) Yeditha Pavan Kumar IHE-Delft and Deltares, The Netherlands Sanjay Giri Deltares, The Netherlands Biswa Bhattacharya IHE-Delft, The Netherlands Acknowledgements Amgad Omer and Victor Chavarrias Deltares, The Netherlands
  2. 2. Presentation outline ❑ Background ❑ Research objectives ❑ Computational modelling ❑ Results and analysis ❑ Conclusions and recommendations
  3. 3. Rivers are major source of surface water! Source: https://openrivers.eu/online/ http://www.bankersexpress.in/list-important-indian-cities-river-banks-download-pdf/ They support the communities on their banks and are considered as a boon. Background
  4. 4. Rivers also cause hazards and disasters due to extreme (natural) hydrometeorological conditions as well as due to human interventions and mismanagement that increase vulnerability and risks! https://www.theatlantic.com/photo/2013/06/early-monsoon-rains-flood-northern-india/100537/ Background
  5. 5. www.tasnimnews.com ✓ Dams are not always used in an optimal way considering their multifunctional aspects. ✓ For example, most of the dams in the region of India with water stress situation during low-flow period are mainly used for irrigation and drinking water supply (and to a lesser degree for hydropower energy). ✓ They do not always consider the flood management and river ecological aspects properly. https://www.brisbanetimes.com. Background Dams in rivers are important measures for water security, green energy as well as for flood management
  6. 6. ✓The main river of Cauvery basin ✓3rd largest river of India – “Ganges of South” ✓It flows through Karnataka, Tamil Nadu, Kerala and Puducherry. ✓Average annual rainfall about 1080 mm (rainfall from South-West and North-East monsoon) ✓Average annual discharge ≈ 700 m3/s ✓21 tributaries - the major ones are Kabini, Hemavathi, Bhavani, Harangi ✓Major dams in the Cauvery River are Krishna Raj Sagar (KRS) and Mettur dams (there are several barrages). ✓There are more than 100 dams in the basin that affects the flow in Cauvery. 1 Cauvery (Kaveri) River Background Courtesy: Central Water Commission About 85% of annual rainfall occurs during the monsoon period! Major floods in 2005, 2007, 2018, 2022 Mettur Dam
  7. 7. ❑ Studying the flood event of 2018 with a focus on the effect of dam operation in the Cauvery River ❑ Investigating the scenarios to assess the flood management capability of Mettur Dam Research objectives The study has been carried out using one-dimensional computational model D-Flow FM 1D coupled with D-Real Time Control (RTC - to simulate reservoir operation)
  8. 8. Details of Cauvery river basin observation stations& dams Longitudinal profile of the modelled river reach Data preparation and the model reach Computational modelling
  9. 9. Computational modelling Full river model for model calibration and verification Reservoir models for scenario simulations Model development
  10. 10. Computational modelling Reservoir operation using D-RTC Model development ✓ D-RTC allows to simulate complex real-time control of all hydraulic structures in reservoirs, rivers and canals systems. This module allows the system to react optimally to actual water levels and discharges by controlling gates, weirs, sluices and pumps. An example of setting up gate operation rule ✓ In this work a simple PID controller and Condition based PID controller are used. ✓ The Parameters which govern the accuracy of PID controller are Kp, Ki and Kd. These are gain factors which govern the optimal operation of variable of interest varying based on deviation of error from optimal value.
  11. 11. Computational modelling Modelling cases, scenarios and boundary conditions ✓ 2018 flood event is used for the model calibration and verification including reservoir operation. ✓ Reservoir operation is based on the data from the same period. ✓ Lateral inflows from tributaries are imposed based on the data (the tributaries inflowing to the reservoir were modelled) Discharge condition at upstream boundary (@Kudige) Q-h relation at Mettur dam
  12. 12. Computational modelling Modelling cases, scenarios and boundary conditions ✓ Simulating various reservoir operation scenarios to assess whether it could be possible to manage 2018 flood in a better way ✓ Simulating scenarios with two structural measures to improve the flood management capability of the dam, viz. (i) lowering the spillway level to increase the flow release from the reservoir, and (ii) increasing the dam height Modelling scenarios and conditions
  13. 13. Result and analysis Model calibration and verification Water level rises faster than the observed level Early gate opening Higher peak outflow Urachikottai, Kodumudi and Musuri indicate the same pattern of early peak and higher peak floods.
  14. 14. Verifying volume-elevation curve of Mettur reservoir Result and analysis Model calibration and verification
  15. 15. Mettur reservoir model (with branches in the model) High peak outflow High low flows Faster rise in water level at elevation 220-225 Slight lower discharge Result and analysis Model calibration and verification
  16. 16. Result and analysis Scenario simulations Mettur reservoir volume and flood volume calculation Date Flood (m3/s) Volume (million m3) Cumulative volume (million m3) Water level in reservoir(m) 09-08-2018 580,84 - 196,9 10-08-2018 1443,3 87.408288 87.40829 209,88 11-08-2018 3568,8 216.52272 303.931 215,85 12-08-2018 3624 310.72896 614.66 221,9 13-08-2018 3183,3 294.07536 908.7353 225,99 14-08-2018 3648,3 251.92512 1160.66 228,88 15-08-2018 3524,4 266.66064 1427.321 231,46 16-08-2018 4502,4 346.75776 1774.079 234,58 17-08-2018 4861,1 404.5032 2178.582 237,83 18-08-2018 5189,4 434.1816 2612.764 240,74 19-08-2018 5485,4 461.15136 3073.915 240,74 20-08-2018 4567,2 434.27232 3508.187 240,64 21-08-2018 3101,4 331.28352 3839.471 240,92 22-08-2018 1175,2 184.74912 4024.22 240,71 23-08-2018 345,48 65.693376 4089.913 240,73 Capacity of Reservoir is 2.6 billion m3 Volume of peak flood: 4.08 billion m3 In dry condition, the reservoir reaches FRL before the arrival of flood peak Flood management capability of the Mettur reservoir
  17. 17. Result and analysis Scenario simulations Scenario 1: Low water release level (234.69 m) Water level condition: Original water level (215.45 m) Case 1.1: Whole period of analysis ▪ Reservoir fills from 01-06-2018 to 15-07-2018 ▪ Although the reservoir remains open, the water level starts increasing after 1st week of August. ▪ The incoming flow is greater than the capacity of the reservoir, hence the dam couldn’t capture the incoming flood peak
  18. 18. Result and analysis Scenario simulations Case 1.2(a) Peak flood analysis Case 1.2 (b) Whole period of analysis Outflow is not zero Flood is not captured Outflow is not zero Flood is not captured Scenario 1: Low water release level (234.69 m)
  19. 19. Result and analysis Scenario simulations Case 1.3(b): Whole period of analysis Outflow is smaller Flood is not captured Case 1.3(a): Peak flood analysis Scenario 1: Low water release level (234.69 m)
  20. 20. Result and analysis Scenario simulations Scenario 2: Low crest level of the spillway (215 m) Water level condition: Original water level (215.45 m) Case 2.1: Whole period of analysis ▪ Outflow is zero during flood peak ▪ Flood is captured in the reservoir ▪ Water level rises and the dam maintains it at FRL ▪ Water level is maintained at 215 until the period of flood peak
  21. 21. Result and analysis Scenario simulations Case 2.2(b): Whole period of analysis Case 2.2(a): Peak flood analysis Outflow is ZERO Flood is captured Scenario 2: Low crest level of the spillway (215 m)
  22. 22. Result and analysis Scenario simulations Case 2.3(b): Whole period of analysis Case 2.3(a): Peak flood analysis Outflow is ZERO Flood is captured ▪ The dam gate closes from 16 August ▪ to 22 August ▪ Flood peak arrives in the reservoir in the same period ▪ The volume of flood captured during this period is 2.59 billion m3. Scenario 2: Low crest level of the spillway (215 m)
  23. 23. Result and analysis Scenario simulations Water level condition: Original water level (215.45 m) Case 3.1: Whole period of analysis ▪ Outflow of dam during smaller flood peak is reduced. ▪ The dam gate closes from 16 August ▪ to 21 August. ▪ Flood peak arrives in the reservoir in the same period. ▪ The volume of flood captured during this period is 2.4 billion m3. Scenario 3: Increase dam height
  24. 24. Conclusions and recommendations Conclusions • The main purpose of Mettur dam in the basin is supply of water for irrigation, drinking water and power generation and does not seem to consider flood management as per the results of data analysis and reservoir operation simulations. • Current reservoir volume and spillway capacity does not seem to be enough for the purpose of flood management. It might be possible only if there is proper monitoring and forecasting system with enough lead time (however, our study showed that the forecasting lead time should be long that is not feasible due to high uncertainties in forecasting). • The results of scenario development showed that by decreasing the release level (scenario 2) and increasing dam height (scenario 3), the reservoir can be used for flood management. However, these options mean large structural interventions that will have social and environmental impacts. This requires further detailed study.
  25. 25. Conclusions and recommendations ❑ Recommendations for model development ▪ Representation of gates at varying level along the dam structure which govern the outflow of the dam cannot be done in 1D model, hence a 2D model can be used for a better representation of the dam and its operation. ❑ Recommendation for flood management ▪ The proposed structural measures, i.e. lowering the spillway crest level and/or increasing the height of the dam should be properly investigated considering impacts and risks. ▪ Application of nature based solutions like retention basin or other approaches can be explored for flood management. ▪ Basin-scale dam analysis can be carried out to improve integrated flow management of the whole basin. Recommendations
  26. 26. Conclusions and recommendations ❑ The developed models cannot be applied to another flood year due to changes in channel bathymetry. ❑ Representation of dam and its gates at different elevations cannot be considered in 1D model. ❑ Effects of the proposed scenarios on other reservoir functions like water supply and irrigation are not considered in this work. Limitations
  27. 27. Thank you for your attention!

×