Transcript Slide 1

Green Water Credits
Use of quantitative tools to evaluate potential
Green Water Credits options
Peter Droogers
Wilco Terink
Johannes Hunink
Sjef Kauffman
Godert van Lynden
Blue and Green Water
Example of potential benefits
Introduction
CONCEPTS BIOPHYSICAL ANALYSIS
Tools and Information
Past
Understand past water resources
Trend
Today
Future
Understand current water resources
Options for future
- technical
- socio-economic
- policy oriented
change
?
•
•
•
•
Observations
Remote Sensing
Analysis
Statistics
• Models
Quantification GWC
Impact
Changes?
Water
Consumption?
Soil Water
Conservation
impact?
Productive
Use?
Water
Demand?
Water
Supply?
GWC Proof
• Observations in field (flows, erosion)
– Precipitation dominant factor
• Large scale
– experimental plots not possible
• Simulation model
– experimental basin in PC
– multiple options can be tested
– various weather conditions (dry-wet)
Tool Selection
continent
Podium
Spatial scale
STREAM
SLURP
basin
WSBM
SWAT
WEAP
system
IQQM
SWAP
AquaCrop
field
high
low
Physical detail
SWAT and WEAP
SWAT
WEAP
(Soil and Water Assessment Tool)
(Water Evaluation And Planning systems)
• Supply analysis
• Demand analysis
• Physical Based
• Conceptual based
• Impact soil-water-conservation
measures
• Benefit – Costs analysis
• Detailed farm management
analysis
• Detailed upstream-downstream
interactions
• Public domain
• User friendly interface
• Public domain
• Very user friendly interface
RIVER BASIN SOIL AND WATER
CONSERVATION
Methodology
• Hydrological models as a tool to simulate the paths
of water and soil movement
• Upstream-downstream interactions
Methodology
• Soil and Water Assessment Tool (SWAT)
•
•
•
•
•
Physically based
Focus on water-erosion-land
management processes
Public domain
Large user-group worldwide
Successfully applied in many
other studies worldwide as well
as in Kenya
Data
• Data sets required:
–
–
–
–
–
–
Digital Elevation Model (DEM)
Climate
Land use and management
Soils
Streamflow
Reservoirs
Data Sources
LAI
Land Cover
Remote
Sensing
Topography
Soils
Climate
Groundwater
Streamflow
Operations
locallysourced
Socio-Economic
nonRS
global
public-domain
Data
Elevation
Landuse
Soils
Climate
Model Reliability
Selection of GWC options
• 11 options explored
•
•
•
•
•
•
•
•
•
•
•
Bench terraces
Conservation tillage
Contour tillage
Fanya Juu terraces
Grass strips
Micro-catchments for planting fruit trees
Mulching
Rangelands
Ridging
Riverine protection
Trash lines
• Labor: intensive vs. extensive
• Investment: low vs. high
• Implementation on 20% of area ~ 100,000 farmers
Results: Key Indicators
• Upstream
–
–
–
–
Crop transpiration
Soil evaporation
Groundwater recharge
Erosion
• Downstream
– Inflow Masinga
– Sediment load Masinga
• Climate
– dry (2005)
– wet (2006)
Scenario
3 Contour tillage
Land
Baseline
4 Fanya Juu terraces
and variations
8 Rangelands
3 Contour tillage
MCT
M
M
9 Ridging
4 Fanya Juu terraces
MCT
and variations10 Riverine protection
5 Grass strips11 Trash lines
MCT
MCT
6 Micro-catchments
for planting fruit trees
2 Conservation
tillage
7 Mulching
M
ra
as
ns
in
ga
pi
ra
So
t
io
il e
n
va
po
ra
tio
Gr
n
ou
nd
w
at
er
Er
re
os
ch
io
ar
n
ge
ti
op
t
Cr
4.2
308
dry
1.1%
0%
wet
1.9%
-21%
dry
0.1%
-1%
1%
0.1%
-1%
1.1%
0.4%
dry dry 931
1.3%
wetwet2508
M
as
an
in
sp
ga
i
r
So
at
io
il e
n
va
po
ra
tio
Gr
n
ou
nd
w
at
er
Er
re
os
ch
io
ar
n
ge
1.2
140
128
7.9
-1%
3%
-23%
0%
2%
-18%
-5%
1%
-2%
1%
-4%
0%
-1%
-10%
0%
-1%
7%
-12%
-21%
1.0
1%
335-1%
4%
121
-23%
16
1.2
-20%
1%
0%
2%
140
-18%
-11%
3080%
7.9
-21% 0%
-10%
0%0%
-1%
1%
3%
-10%
-23%
-8%
-21% 0%
0%-1%
2%
0%
-8%2%
-18%
1%
-5%
3%
-9%
Cr
op
0%
ti
-21%
tr
nf
lo
w
2508
dry
16
use*M Yearwet
MCM/y
Mton/y
mm/y**
mm/y**
mm/y***
ton/ha/y***
0.8%
-7%
0%
0%
3%
-6%
5 Grass strips
1 Bench terraces
im
en
wet
wet
121
im
en
M
335
In
f
2 Conservation tillage
1.0
ga
MCT
931
as
in
1 Bench terraces
dry
M
Baseline
Year MCM/y Mton/y mm/y** mm/y** mm/y*** ton/ha/y***
Se
d
Land use*
lo
w
Scenario
nf
lo
w
ga
as
in
In
f
Se
d
lo
w
M
Results: Key Indicators
MCT
MCT
dry
drywet 1.1%
0.6%
0.6%
wetdry 1.9%
wet
0.6%
-6%
0%
0.4%
-6%
3%
wetwet 0.1%
0.5%
-1%
-6%
2%
0.1%
drydry 1.1%
dry
MCT
AR
M
MCTA
MCT
0.6%
4.2
0%
-5%
1%-12%
-4%
-10% 0%
wetdry 0.8%
1.4%
-7%
-18%
128
-14%
1%
-2%
-4%
2%
-8%0%
-1%
0%-3%
1%
-1%
-4%7%
-12%
0%
0%-1%
0%
23%
3%
-21%
-6%
1.0%
drywet 0.4%
-12%
-21% 0%
1%-1%
10%
-1%
-12%
4%
-23%
0.0%
wetdry 1.3%
-5%
0%
2%
-18%
drydry 0.6%
0.6%
0%
0%
0%
-5%
-4%
1%-1%
-11% 0%
-7%
-6%
-10% 1%
wet
wet
0.0%
0.0%
0.6%
wetwet 0.6%
-1%
3%
1%
dry
0.1%
-1%
-2%
-20%
*M=Ma i ze, C=Coffee, T=Tea ,A=Agri cul tura l ASAL, R=Ra ngel a nds ;
6 Micro-catchments
dry
** Agri cul tura l a reaMCT
s ; *** Ba s i n-wi de;
for planting fruit trees
wet
0%
-12%
-2%
0%
0%
-6%
0%-3%
0%
-1%
3%
-4%
-8%3%
-14%
0%-2%
1%
0%
-5%1%
-10%
0.6%
-8%
0%
-1%
2%
-8%
0.6%
-6%
0%
0%
1%
-5%
Results: Spatial
OVERALL BENEFIT-COST ANALYSIS
WEAP Tool
• Impact of changes in water-soil dynamics on:
– upstream
• rainfed improved production
– downstream
• hydropower
• domestic water supply
• irrigation
• Benefit-cost analysis
• Integrations tool: WEAP
WEAP Tool
WEAP: Validation
Masinga Inflow
Masinga Outflow
Kamburu Outflow
Gitaru Inflow
Kindaruma Outflow
Kiambere Outflow
Results: Reduction in water shortage
Unmet Demand
All Demand Sites (13), All months (12)
00_Base
01_Bench
02_ConsTill
03_ContTill
04_FanyaJuu
05_GrassStrips
06_MicroCatchments
07_Mulching
08_Rangelands
09_Ridging
10_Riverine
11_TrashLines
0.0
-0.5
-1.0
Million Cubic Meter
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
-4.5
-5.0
-5.5
-6.0
-6.5
-7.0
2005
Results: Increase in hydropower
Hydropow er Generation
All Reservoirs (9), All months (12)
00_Base
01_Bench
02_ConsTill
03_ContTill
04_FanyaJuu
05_GrassStrips
06_MicroCatchments
07_Mulching
08_Rangelands
09_Ridging
10_Riverine
11_TrashLines
180
Thousand Gigajoule
160
140
120
100
80
60
40
20
0
2005
Results: Increase in Benefits
Results: Benefit-Cost Analysis
Benefits
Benefits
01_Bench
01_Bench
02_ConsTill
02_ConsTill
03_ContTill
03_ContTill
04_FanyaJuu
04_FanyaJuu
05_GrassStrips
05_GrassStrips
06_MicroCatch
06_MicroCatch
07_Mulching
07_Mulching
08_Rangelands
08_Rangelands
09_Ridging
09_Ridging
10_Riverine
10_Riverine
11_TrashLines
11_TrashLines
mUS$/y
mUS$/y
9.9
9.9
1.0
1.0
4.9
4.9
9.0
9.0
5.3
5.3
1.6
1.6
5.1
5.1
0.8
0.8
8.9
8.9
2.0
2.0
3.4
3.4
Costs
Costs
ha
ha
92,865
92,865
52,766
52,766
52,766
52,766
92,865
92,865
92,865
92,865
1,000
1,000
92,865
92,865
136,916
136,916
52,766
52,766
10,000
10,000
92,865
92,865
B/C
B/C
Construction
Construction Maintenance
Maintenance
US$/ha
US$/ha
US$/ha
US$/ha/y
/y
mUS$/y
mUS$/y
100
100
20
20
2.8
2.8
00
00
0.0
0.0
00
00
0.0
0.0
200
200
20
20
3.7
3.7
50
50
20
20
2.3
2.3
500
500
20
20
0.1
0.1
00
00
0.0
0.0
50
50
00
0.7
0.7
100
100
20
20
1.6
1.6
100
100
20
20
0.3
0.3
50
50
20
20
2.3
2.3
• 20% of area ~ 100,000 smallholders
mUS$
mUS$
7.1
7.1
1.0
1.0
4.9
4.9
5.3
5.3
3.0
3.0
1.5
1.5
5.1
5.1
0.1
0.1
7.3
7.3
1.7
1.7
1.1
1.1
DISCUSSIONS, CONCLUSIONS
Conclusions
• GWC beneficial for:
– upstream
– downstream
• Analysis tools:
– SWAT: (upstream) supply
– WEAP: (downstream) demand
• Steps
– Understand current situation
– Explore options
• GWC
–
–
–
–
Biophysical component
Socio-economics
Institutional
Financial
Discussion / conclusions
• Smaller focus area
– current study: 1.8 million ha total; 0.5 million ha rainfed
• Definition of GWC options
– effectiveness of implementation
• Convincingness of current approach
– Rainfed farmers
– Downstream beneficiaries
• Monitoring system
THANK YOU