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Nam Songkhram model application and field work
National consultation with TNMC20th 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
Nam Songkhram application areas
Area: 13,126 km2
Elevation:• min 135 m amsl• max 675 m amsl
4
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
Ban Tha Kok Daeng
Ban Tha Sri Chomchun
Ban Phok Yai
Ban Khon Sai
Ban Nong Yang
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 0
100
200
300
400
500
600
700
1 2 3 4 5 6 7 8 9 10 11 12
month
av
era
ge
mo
nth
ly r
ain
fall
su
m (
mm
) Waritchaphum
Ban Tha Kok Daeng
Bung Kan
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
130
132
134
136
138
140
142
144
146
148
-400 -300 -200 -100 0 100 200 300 400
132
134
136
138
140
142
144
-100 -50 0 50 100
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
0
100
200
300
400
500
600
700
800
900
1 2 3 4 5 6 7 8 9 10 11 12
month
aver
age
mo
nth
yl d
isch
arge
(m3/s
)
Min
Avarage
Max
12
Field work at Ban Chai Buri - location
13
Current meter RCM9
Current speed Current direction Temperature Conductivity Pressure Turbidity Oxygen
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Current speed & direction
Mekong
Current Speed at Ban Chai Burifrom 16 June to 28 August 2005
0
40
80
120
160
6,5 7,0 7,5 8,0 8,5 9,0
Time (Month)
Cu
rre
nt S
pe
ed
, cm
/s
Current Direction at Ban Chai Buri
from 16 Jun to 28 August 2005
0
10
20
30
40
50
60
6,5 7,0 7,5 8,0 8,5 9,0
Time (Month)
Cu
rre
nt d
ire
ctio
n, D
eg
.M
Water Level at Nakhon Phanomfrom 16 June to 28 August 2005
0
2
4
68
10
12
14
6,5 7,0 7,5 8,0 8,5 9,0
Time (Month)
Wa
ter
leve
l, m
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
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
VMod calibration
red line observed, black line calculated
21
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
VMod verification
red line observed, black line calculated
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)
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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
River Dry season Wet season Maximum flow
Minimum flow
Nam Songkhram - 1 % + 5 % + 7 % - 13 %
Huai Hi - 6 % + 6 % + 8 % - 5 %
Huai Khong + 3 % + 6 % + 8 % - 4 %
Nam Oon - 14 % - 5 % - 2 % - 32 %
Nam Yam - 4 % + 0 % + 2 % - 6 %
34
Climate change A2
Baseline
20/08/2001
35
Baseline
Climate change B2
20/08/2001
36
Baseline
20/08/2001
Land use change
37
Baseline
05/08/1997
Upstream development
38
Baseline
05/08/1997
Irrigation
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
MRCS/WUP-FINwww.eia.fi/wup-fin
Thank You!