1. SCIENCE WORKSHOP : Volta Basin
Development Challenge of the CPWF
Annual reflection meeting
Hydrological Modeling-CPWFV3
03th-05th july , 2012
Presented by
Frank ANNOR, KNUST-TUDelft
FOWE TAZEN, 2iE Foundation

2. Presentation Outline
1. Background
2. Methodology
i. Instrumentation
ii. Modeling
3. Initial Results
4. Way forward
Andes • Ganges • Limpopo • Mekong • Nile • Volta

3. Background
Morphometric characteristics of
Boura catchment
Surface area (km²) : 155.3
Perimeter (m)
: 59.6
Compactness index : 1.34
Mean elevation (m) : 300
Specific elevation(m) : 37.24
Mean slope (m/km) : 3.4%
Global slope index(m/km) : 4
Andes • Ganges • Limpopo • Mekong • Nile • Volta
Morphometric characteristics of
Binaba catchment
Surface area (km²): 11.8
Perimeter (m)
: 14.6
Compactness index : 1.2
Mean elevation (m) : 225
Specific elevation (m) : 23.80
Mean slope (m/km) : 0.35%
Global slope index (m/km) : 6.9

4. Background
× No hydrological monitoring
– Boura and Binaba watersheds
are ungauged
• No records of streamflow,
evaporation, water level etc
• Difficult to calibrate a
hydrological model in the
basin at a small watershed
without these records
× Management (allocation) of
water has not been streamlined
especially for the dry season
Objectives
 Physical and hydrological




characterization of watersheds of
both sites
Building of the monthly
streamflow time series
Establish the water budget of
each reservoir
Determine the heat balance of
the reservoir
Model GW-SW interactions
Andes • Ganges • Limpopo • Mekong • Nile • Volta

5. TU-Delft
2IE
 Developing a Hydrological model
(Yates, GIRARD & GR2M)
 Developing a water allocation
model using WEAP at a smaller
watershed level (Boura and
Binaba) using the water balance
 Water Use
 Other components of the water
balance i.e Runoff, P,ET, etc
 Evaporation and seepage losses
in lakes in the Volta basin using
water and heat balance
 Detailed study in Binaba &
(Boura?)
 Regionalising for the basin using
remote sensing (Images through
the TIGER project)
 Groundwater surface water
interactions (natural Isotopes)
Andes • Ganges • Limpopo • Mekong • Nile • Volta

6. Methodology
Andes • Ganges • Limpopo • Mekong • Nile • Volta

7. Water budget of the reservoir
Boura only
?
?
?
Andes • Ganges • Limpopo • Mekong • Nile • Volta

8. Getting the water balance right ..1
gauge plates
Rain gauge
Evaporation pan
Monitoring well
DTS
EC
Andes • Ganges • Limpopo • Mekong • Nile • Volta

9. Getting the water balance right …2
Thalimedes
Water Sampling Points
for Isotope analyses
Rainfall Sampling
Andes • Ganges • Limpopo • Mekong • Nile • Volta

10. Modelling
Diagnostic
Analyses of
Users/Typologies
(Uses)
Model Output
from ZonAgri
Evaporation &
Seepage Losses
model output
Andes • Ganges • Limpopo • Mekong • Nile • Volta
Output from
other
hydrological
models

11. Some initial results
Ecoulement moyen mensuel(mm/mois)
Lame_GR2M
Lame_Yates
16.00
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
Seasonal flows in Boura
Andes • Ganges • Limpopo • Mekong • Nile • Volta
Lame_Girard

12. Some initial results
Annual flows
Andes • Ganges • Limpopo • Mekong • Nile • Volta

13. Some initial results
Yates
Girard
60.00
50.00
40.00
30.00
20.00
10.00
0.00
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
Ecoulements maxima mensuels par an
(mm)
GR2M
Maximum monthly flows per year
Andes • Ganges • Limpopo • Mekong • Nile • Volta

14. Some initial results
Modèle
GR2M
Yates
Girard
Lame écoulée annuelle
moyenne (mm)
36.02
31.6
34.79
Lame écoulée annuelle
médiane(mm)
34.21
28.4
35.3
Ecart-type (mm)
16.84
17.6
20.85
Coefficient Variation (%)
46.77
57.74
59.92
Coefficient d'écoulement
annuel moyen (%)
3.94
4.66
5.56
Maximum monthly flows per year
Andes • Ganges • Limpopo • Mekong • Nile • Volta

15. Some initial results
Isotope Analysis
Andes • Ganges • Limpopo • Mekong • Nile • Volta

16. Some initial results
Water Temperature at bottom of lake
600
25
500
20
400
15
300
10
200
5
100
0
0
Date/Time
Binaba reservoir
Andes • Ganges • Limpopo • Mekong • Nile • Volta
Water level (m)
700
30
Temperature (oC)
35

17. Way Forward
More data collection
Calibration and verification of models
Scenario
building
(climate
change, water uses, cropping pattern)
Andes • Ganges • Limpopo • Mekong • Nile • Volta

18. Thank you for
your attention
Andes • Ganges • Limpopo • Mekong • Nile • Volta