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Nam Songkhram model application and field work

Nam Songkhram model application and field work. National consultation with TNMC 20th of April 2006, Bangkok MRCS WUP-FIN. Outline. Models applied and model areas Input data Cross sections Field measurements Satellite images Etc. HBV and VMod hydrological models Calibration results

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Nam Songkhram model application and field work

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  1. Nam Songkhram model application and field work National consultation with TNMC 20th of April 2006, Bangkok MRCS WUP-FIN

  2. Outline • Models applied and model areas • Input data • Cross sections • Field measurements • Satellite images • Etc. • HBV and VMod hydrological models • Calibration results • Validation results • Scenarios • VMod manual • 3D Hydrodynamic model • Calibration results • Validation result • Scenarios • Development and continuation • 3D EIA model manual

  3. Area: 13,126 km2 Elevation: min 135 m amsl max 675 m amsl Nam Songkhram application areas

  4. Ban Tha Sri Chomchun Ban Nong Yang Ban Tha Kok Daeng Ban Khon Sai Ban Phok Yai HBV Hydrological Model • Simple lumped hydrological model • HBV model has been set up for five subcatchments in the Nam Songkhram watershed • The size of the model areas varies between 625 and 5029 km2 • Simple optimisation of the model parameters completed with good results

  5. VMod Hydrological model • 2D distributed hydrological model coupled with a 1D hydrodynamic river, reservoir and lake model • Physical model of the application area that takes into account variability in elevations, soil properties, vegetation, land use etc. • 1 km model grid • Flow network computed from DEM and corrected • 5 landuse classes and 5 soil classes • Calibration with five discharge stations is finished

  6. EIA 3D Hydrodynamic model • 3D hydrodynamic model coupled with a water quality model • 500 m grid resolution for floodplain, 50-500 for rivers • 3D hydrodynamics • flood arrival time, duration and depth in different locations of the modelled area, other flood characteristics • Water quality: sediment concentration, net-sedimentation, oxygen, etc • Run through a GIS-type graphical user interface

  7. Input data • Models applied and model areas • Input data • Cross sections • Field measurements • Satellite images • Etc. • HBV and VMod hydrological models • Calibration results • Validation results • Scenarios • VMod manual • 3D Hydrodynamic model • Calibration results • Validation result • Scenarios • Development and continuation • 3D EIA model manual

  8. Input data status – Hydrological models • Digital elevation model • 50 m resolution • Landuse maps (several years, newestfrom 2002) • Soil map • Weather data • 16 precipitation stations • Temperature data from one station • Evaporation, few stations • Flow and water level data • five stations

  9. New data • Pumping data • Data from irrigation projets and structures • Total volumes 675 million m3 • Most (520 million m3) is from Nam Oon • Water Quality data • Satellite images to show the flood extent • Field measurements • Ground water depth

  10. New data, cross sections • Cross sections • 400 cross sections from Nam Songkhram and its tributaries • Have now been digitalized and quality checked • The general information of the cross sections was added to the model

  11. Input data status – EIA 3D Hydrodynamic model • Digital elevation model • 50 m resolution • Channel cross-section data • Landuse maps (several years, newestfrom 2002) • Boundary conditions • Upstream (discharge): Ban Tha Kok Daeng + sub-tributaries & Mekong upstream • Downstream (rating curve): Mekong at Nakhom Phanom • Water level • Flood extent based on satellite images • Field data

  12. Field work at Ban Chai Buri - location

  13. Current meter RCM9 • Current speed • Current direction • Temperature • Conductivity • Pressure • Turbidity • Oxygen

  14. Current speed & direction Mekong

  15. HBV and VMod hydrological models • Models applied and model areas • Input data • Cross sections • Field measurements • Satellite images • Etc. • HBV and VMod hydrological models • Calibration results • Validation results • Scenarios • VMod manual • 3D Hydrodynamic model • Calibration results • Validation result • Scenarios • Development and continuation • 3D EIA model manual

  16. HBV calibration results The R2 in calibration period (1987-1991) was • 0.92 for Nam Songkhram at Ban Tha Kok Daeng • 0.80 for Nam Oon at Ban Phok Yai • 0.75 for Nam Yam at Ban Khon Sai • 0.84 for Huai Khong at Ban Tha Sri Chomchun • 0.86 for Huai Hi at Ban Nong Yang red line observed, black line calculated

  17. HBV validation results The R2 of the validation period (1992-1995) was • 0.83 for Nam Songkhram at Ban Tha Kok Daeng • 0.81 for Nam Oon at Ban Phok Yai • 0.70 for Nam Yam at Ban Khon Sai • 0.70 for Huai Khong at Ban Tha Sri Chomchun • 0.76 for Huai Hi at Ban Nong Yang red line observed, black line calculated

  18. VMod program: new developments • Pumping • it is now possible to substract (or add) water from the river (for irrigation) • Regulation • it is now possible to regulate lakes / reservoirs (Nam Oon reservoir) • Improvements in the model calculations

  19. VMod: New development in Nam Songkhram • River data and friction coefficients have been modified • Model has been calibrated • Water quality component has been included, but not yet calibrated • Preliminary (sensitivity) scenarios have been simulated

  20. red line observed, black line calculated VMod calibration • Calibration of the VMod application for Nam Songkhram is ready • The R2 in calibration period (1989-1991) was • 0.90 for Nam Songkhram at Ban Tha Kok Daeng • 0.69 for Nam Oon at Ban Phok Yai • 0.66 for Nam Yam at Ban Khon Sai • 0.78 for Huai Khong at Ban Tha Sri Chomchun • 0.82 for Huai Hi at Ban Nong Yang

  21. red line observed, black line calculated VMod verification • The R2 in test period (1992-1995) was • 0.86 for Nam Songkhram at Ban Tha Kok Daeng • 0.76 for Nam Oon at Ban Phok Yai • 0.78 for Nam Yam at Ban Khon Sai • 0.71 for Huai Khong at Ban Tha Sri Chomchun • 0.58 for Huai Hi at Ban Nong Yang

  22. VMod manual • New version of the VMod manual has been prepared

  23. HBV and VMod hydrological models • Models applied and model areas • Input data • Cross sections • Field measurements • Satellite images • Etc. • HBV and VMod hydrological models • Calibration results • Validation results • Scenarios • VMod manual • 3D Hydrodynamic model • Calibration results • Validation result • Scenarios • Development and continuation • 3D EIA model manual

  24. Modelling: 3D new developments • Channel dimensions and elevations have been modified • Model parametrization has been modified to stabilize the model • Model has been calibrated and validated against satellite data from flood extent and water levels • Preliminary scenarios have been calculated

  25. Flood duration Flood arrival time

  26. Calibration results 17/09/2000

  27. Calibration results 04/11/2000

  28. Verification results 20/09/2001

  29. Effect of Mekong to Nam Songkhram • Backwater effect (Mekong prevents Nam Songkhram outflow) • Has clear effect to flooded areas in Nam Songkhram • The effects can be seen in the model simulations • Reverse flow (Mekong flows into Nam Songkhram) • Depends on the size of the Mekong flood and on the timing of Mekong and Nam Songkhram floods • Greatest when Mekong flood is ahead on the flood in Nam Songkhram

  30. Flood depth- Mekong water level low Flood depth- Mekong water level high

  31. Reverse flow maximum 1999 Reverse flow maximum 1997

  32. Scenarios SRES A2 and B2 climate scenarios for 2070-2099 provided by Hoanh et al. (2003) • Climate change • A2: T = +4.0 C, E = +9.5 %, P = +6.6 %, Mekong = +17 % • B2: T = +2.9 C, E = +6.9 %, P = +0.9 %, Mekong = +6 % • Land use change • Decidious forest – 80 % (from 6 % to 1 %) • Upstream development • DSF upstream development scenario (high development) • Irrigation (upstream and in basin) • DSF upstream irrigation scenario + more irrigation in Nam Songkhram (-5 % NS at BTKD, Nam Yam and Huai Hi)

  33. Procedure • First changes made to VMod input data • Example of the Climate change scenario A2, results from VMod • VMod results used as a new boundary conditions to the EIA 3D model

  34. Climate change A2 Baseline 20/08/2001

  35. Climate change B2 Baseline 20/08/2001

  36. Land use change Baseline 20/08/2001

  37. Upstream development Baseline 05/08/1997

  38. Irrigation Baseline 05/08/1997

  39. Future tasks • Calibrate the water level in the locations where data available • Calibrate the water quality and erosion components to the model • Clarify and execute official scenarios (e.g. irrigation, land use and climatological changes)

  40. Potential use of the model set • Impact of the local and basin wide development on the flooding, water quality, etc • Impact of the climate change (better data of climate change scenarios from SEA START RC) • Landuse change impacts on the hydrology and water quality • Fisheries research • Ecosystem functions and productivity issues (productivity related to the flooded area, vegetation, water quality) • Model basis of the possible flood forecasting work

  41. Working paper • All the information collected there • Will be updated continuosly • Newest version by request

  42. www.eia.fi/wup-fin • Content of the project’s two phases • Personnel & contact details • Documents downloadable • Training portfolio: presentations, documents, exercises

  43. Thank You! MRCS/WUP-FINwww.eia.fi/wup-fin

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