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