outline of the training
DESCRIPTION
Outline of the training. . 6 October 2005, TNMC, Bangkok. Training objectives. updating the data and model development issues deepening the knowledge of the EIA 3D hydrodynamic models with practical training planning of the future activities. Schedule. Brushing up. - PowerPoint PPT PresentationTRANSCRIPT
Outline of the training
. 6 October 2005, TNMC, Bangkok
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Training objectives
updating the data and model development issues deepening the knowledge of the EIA 3D
hydrodynamic models with practical training planning of the future activities
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Schedule
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Brushing up....
HBV and VMod hydrological models• Validation results• Development and continuation• VMod manual
3D Hydrodynamic model• Current status of the application• Validation• Development and continuation
Field work• Preliminary results from the field work in Si Songkram
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Nam Songkhram application area
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HBV and VMod
Data Latest results Continuation
Ban_Tha_Kok_Daeng 67,108
Nam_Oon_Dam 64,44
Ts2 138,80
Huai_Khong 44,131
Nam_Oon 87,49
Nam_Yam 63,73
Huai_Hi 87,111
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Elevation
13126 km2
Heights• min 135m• max 675 m
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SAHATSAKHAN
KUMPHAWAPI
NONG_HAN PHANNA_NIKHOM
SAWANG_DAEN_DIN
PHEN
WARITCHAPHUM
SAKON_NAKHON
THA_UTHEN NAKHON_PHANOM
SISONGKHRAM
BAN_PHAENG PHON_PHISAI
BUNG_KAN
BAN_THA_KOK_DAENG SO_PHISAI
BAN_THA_KOK_DAENG/TEMP
Weather data
16 precipitation stations
Temperature data from one station
Evaporation, three stations used
Some data gaps• Temperature missing 1994-
2002• Some days and months
missing in Pan evaporation
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1175
1432
2366
1339 1254
1128
1564
2290
2665
1796
1446
2943
1976
1984
1850 1979
Average yearly precipitation
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Modelling: HBV
HBV model has been set up for five subcatchments in the Nam Songkhram watershed
The size of the model areas is between 625 and 5029 km2
Ban Tha Kok Daeng
Ban Tha Sri Chomchun
Ban Phok Yai
Ban Khon Sai
Ban Nong Yang
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Modelling: HBV
Simple optimisation of the model parameters completed
Model results in calibration period (1987-1991) very good to moderately good
Model result in test period (1992-1995) good to moderately good
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The R2 in calibration period was• 0.92 for Nam Songkhram at Ban Tha Kok Daeng• 0.81 for Nam Oon at Ban Phok Yai• 0.74 for Nam Yam at Ban Khon Sai• 0.86 for Huai Khong at Ban Tha Sri Chomchun• 0.86 for Huai Hi at Ban Nong Yang
The R2 of the test period (1992-1995) was• 0.83 for Nam Songkhram at Ban Tha Kok Daeng• 0.81 for Nam Oon at Ban Phok Yai• 0.73 for Nam Yam at Ban Khon Sai• 0.77 for Huai Khong at Ban Tha Sri Chomchun• 0.76 for Huai Hi at Ban Nong Yang
HBV results
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Modelling :VMod
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.
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Landuse/Irrigated area
Landuse (1997) types are• Water• Agriculture• Irrigated agriculture• Evergreen/mixed forest• Deciduous forest/scrub
89% of landuse agriculture or irrigated agriculture
Irrigated 3280 km2 (24% of catchment, 2001)
New landuse data (2002)
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Soils
Five soil types
80 % acrisol/plintic acrisol
Low water retention and conductivity
water
floodplain
alluvial soils
(plinthic) acrisol
slope complex
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Modelling: VMod
1 km model grid (resolution can and probably will be increased)
Flow network computed from DEM and corrected
The number of landuse and soil classes has been reduced to make the calibration and use of the model easier and clearer
5 landuse classes
5 soil classes
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Modelling: VMod, newest developments
Data from four new discharge station added to the model
Calibration of the model has continued with this new data
New developments of the irrigation practices include the possibility to subtract water from the river to be used in irrigation
Ban_Tha_Kok_Daeng 67,108
Nam_Oon_Dam 64,44
Ts2 138,80
Huai_Khong 44,131
Nam_Oon 87,49
Nam_Yam 63,73
Huai_Hi 87,111
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Computed flow at Ban Tha Kok Daeng compared to measured data
The results are much better than the previous results, but there is still room for more improvement
R2 is 0.91 in calibration period, 0.84 in test period
VMod flow computations, Ban Tha Kok Daeng
07/89 01/90 07/90 01/91 07/91 01/92 07/92
200
400
600
800
1000
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The other four stations with discharge measurement have been included in the model and their calibration is only in the beginning
The computed vs. measured in these new stations is not as good as in Ban Tha Kok Daeng
The R2 in calibration period was• 0.55 for Nam Oon at Ban Phok Yai (there are still problems with
irrigational practices and with the Nam Oon dam here)• 0.65 for Nam Yam at Ban Khon Sai• 0.58 for Huai Khong at Ban Tha Sri Chomchun• 0.80 for Huai Hi at Ban Nong Yang
VMod flow computations, other stations
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VMod: Future tasks
Develop further the agricultural water practices (water trapping, discharge and evaporation from paddy fields etc.)
Check the floodplains in the hydrological model
Add structures that may affect flow
Check river dimensions (cross sections)
Further calibration of the model
Include water quality and erosion components to the model and calibrate these
Clarify and execute scenarios (e.g. irrigation, land use and climatological changes)
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EIA 3D Model
Latest development Some preliminary results
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3D hydrodynamic and WQ application
3D hydrodynamic model coupled with a water quality model
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
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Input data for the 3D model
River and floodplain topography• Hydrographic atlas data • river cross-sections for Nam Songkhram • digital elevation map (DEM) for floodplain
Boundary conditions• Upstream discharge and water level in Mekong• Upstream dishcarge in Nam Songkhram• Downstream rating curve (in Mekong)
Landuse Wind (Precipitation)
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Modelling: 3D
The main tribuaries of the Nam Songkhram have been included in the model (Nam Oon, Nam Yam, Huai Hi...)
Model calculation have been visually compared to data from inundated areas
Effect of Mekong mainstream waterlevel (backwater effect)
Sensitivity to parameter values has been analysed
Channel dimension and elevations have been modified (still in progress)
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Digital elevation model and model area
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3D view on the wetlands
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Inundation on Sept 2000
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3D model grid for NSK model
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Model animation window
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Flood duration
Flood arrival time
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Flood depth-
Mekong water level low
Flood depth-
Mekong water level high
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Output
Tool to understand the hydrodynamic of the Nam Songkhram flood plains
Scenarios and their impact on the flooding• Landuse• Climate change• Irrigation development• Reservoir development
Interaction between Nam Songkhram and Mekong• Reverse flow• Back water effect
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EIA 3D modelling: Future tasks
Include new river cross sections in to the model
Check grid heights
Include structures that affect flow (enbankments, dams, weirds)
Calibrate and verify the model
Include water quality calculations
Clarify and execute scenarios (e.g. irrigation, land use and climatological changes)
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Field work at Si Songkram - location
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Current meter RM9
Current speed Current direction Temperature Conductivity Pressure Turbidity Oxygen
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Current speed & direction
Current Direction at Si Songkramfrom 16 Jun to 4 August 2005
0
10
20
30
40
50
60
6.0 6.5 7.0 7.5 8.0 8.5
Time (Month)
Cur
rent
dire
ctio
n, D
eg.M
Current Speed at Si Songkramfrom 16 June to 4 August 2005
0
40
80
120
160
06/01 06/01 07/01 07/01 08/01 08/01
Time (Month)
Cu
rre
nt S
pe
ed
, cm
/s
Mekong
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Vientiane – Nong Khai bank erosion study
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Vientiane – Nong Khai: 50m grid
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Vientiane – Nong Khai: model results
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Field work at Vientiane – Nong Khai
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Field work at Vientiane – Nong KhaiFlow velocity
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Field work at Vientiane – Nong KhaiBackscatter
MRCS/WUP-FINwww.eia.fi/wup-fin