Transcript Water, Climate, Food, and Environment in Walawe Basin, Sri

Basin scale hydrology
scenarios
to explore Green Water Credits opportunities
Peter Droogers, SEI
Questions to be answered

What is the present delivery and use of green
and blue water?

What is the potential incremental green and
blue water gains?
Why models?
Past
Understand past water resources
Trend
Today
Future
Understand current water resources
Options for future
- technical
- socio-economic
- policy oriented
?
•Remote Sensing
•Observations
•Analysis
•Statistics
•Models
Data  Information  Knowledge  Policies
Why modeling tools
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Modeling
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Understanding processes
Scenario analysis (what, if)
Green Water Credits

Proof of GWC sellers delivery
• e.g. less sedimentation, more blue water delivered
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Proof of GWC buyers benefits
• e.g. less siltation, more hydropower generation, more relibale
drinking water
Modeling tools
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SWAT
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WOFOST
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Supply analysis, basin scale
Detailed crop analysis
WEAP

Demand size allocation and benefits
SWAT
Soil Water Assessment Tool
Upland Processes
Channel/Flood Plain
Processes
Land processes
Evaporation and
Transpiration
Precipitation
Root Zone
Infiltration/plant uptake/
Soil moisture redistribution
Vadose
(unsaturated)
Zone
Shallow
(unconfined)
Aquifer
Surface Runoff
Lateral Flow
Revap from
shallow aquifer
Percolation to
shallow aquifer
Return Flow
Confining Layer
Deep (confined)
Aquifer
Flow out of watershed
Recharge to
deep aquifer
SWAT Upper Tana
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
tana_srtm
(m)
<0
0 - 25
25 - 50
50 - 100
100 - 200
200 - 300
300 - 400
400 - 500
500 - 600
600- 700
700 - 800
800 - 900
900 - 1,000
1,000 - 1,100
1,100 - 1,200
1,200 - 1,300
1,300 - 1,400
1,400 - 1,500
1,500 - 1,600
1,600 - 1,700
1,700 - 1,800
1,800 - 1,900
1,900 - 2,000
2,000 - 2,500
2,500 - 3,000
3,000 - 3,500
3,500 - 4,000
4,000 - 5,000
5,000 - 6,000
Tana River
Green Water Credits
0
25
50 Km
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
Tana River
Green Water Credits
0
25
50 Km
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
Garba Tula
Isiolo
Lare
Rumuruti
Mikinduri
Meru
Kaongo
Timau
Nanyuki
Usueni
Chiokarige
KahigainiNyeri
Gilgil
Manyata
Garissa
Embu
Ngomeni
Githunguri
Naivasha
Waita
Mareira
KijabeMagina
Thika
Tana River
KiambuRuiru
Nairobi
Tulia
Kangundo
DRSRS Land use map, 101 classes
Green Water Credits
0
25
50 Km
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
KenSOTER
FAO
CMc
CMx
FRr
LVh
LXh
NTr
NTu
PHl
PLe
RGd
SNh
VRe
Tana River
Green Water Credits
0
25
50 Km
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
Garba Tula
Isiolo
Rumuruti
,
%
,
%
Lare
, Mikinduri %
%
,
Timau
Nanyuki
,
%
,
%
,
%
,
%
,
%
,
%
Meru
Kaongo
Usueni
,
%
,
%
KahigainiNyeri
,
%
,
%
Chiokarige
Manyata
Garissa
Embu
Naivasha
Ngomeni
Githunguri
,
%
Mareira
,
%
KijabeMagina
Kiambere
,
%
,
%
Waita
Kamburu
Masinga
,
%
,
%
,
%
Tana River
Thika
Green Water Credits
KiambuRuiru
,% Nairobi
Tulia
,
%
Kangundo
,
%
,
%
,
%
,
%
,
%
0
25
50 Km
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Watershed
delineation
Land use
Soils
Climate
HRU
Results
Tana River
Green Water Credits
0
Hydrological Response Units = unique combinations
25
50 Km
SWAT Results
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Preliminary Results
 Proof of Concept
 Initiate Discussions
Actual evapotranspiration
HRUs
sbs1997.ETMM
0 - 250
251 - 500
501 - 600
601 - 700
701 - 800
801 - 1000
1001 - 1500
1501 - 2000
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Actual transpiration (Green Water)
HRUs
sbs1997.TACT
0 - 100
101 - 200
201 - 300
301 - 400
401 - 500
501 - 750
751 - 1000
1001 - 2000
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Soil evaporation
HRUs
sbs1997.EACT
0 - 100
101 - 200
201 - 300
301 - 400
401 - 500
501 - 600
601 - 750
751 - 1000
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Blue Water (runoff)
HRUs
sbs1997.WYLDMM
0
1 - 250
251 - 500
501 - 750
751 - 1000
1001 - 1250
1251 - 1500
1501 - 1750
1751 - 2000
2001 - 3000
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Groundwater recharge
HRUs
sbs1997.DA_RCHGMM
0 - 10
11 - 20
21 - 30
31 - 50
51 - 75
76 - 100
101 - 150
151 - 200
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Erosion
HRUs
sbs1997.SYLDTHA / <None>
0-5
5 - 15
15 - 25
25 - 50
50 - 75
75 - 100
100 - 150
150 - 200
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Scenarios
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Enhance Green Water Use
Reduce
Soil Erosion
R E FE R E N CE
E N H A N CE W P
R E D U C E E R O SIO N
T R A N SP IR A TIO N A G R L 199 7 ( M M / Y )
248
276
248
T FR A C T IO N A G R L 199 7 (% )
38.2
41.5
38.2
E R O SIO N A G R L 1997 ( T / H A )
23.8
22.8
12.0
R E FE R E N CE
E N H A N CE W P
R E D U C E E R O SIO N
T R A N SP IR A TIO N A G R L 199 7 ( M M / Y )
248
276
248
T FR A C T IO N A G R L 199 7 (% )
38.2
41.5
38.2
E R O SIO N A G R L 1997 ( T / H A )
23.8
22.8
12.0
Erosion reduction (%)
HRUs
Scen_01.SYLD% / <None>
< 25 %
25 - 50 %
50 - 75 %
75 - 100 %
0
25
50
100 Km
Tana Basin, Kenya
Green Water Credits
Next Steps
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Feedback!
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Some additional data
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Suggestions for scenarios
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Link with other approaches (WOFOST, WEAP)
Thank You