Green Water Credits
description
Transcript of Green Water Credits
Green Water Credits
Use of quantitative tools to evaluate potentialGreen Water Credits options
Peter DroogersWilco Terink
Johannes HuninkSjef Kauffman
Godert van Lynden
Blue and Green Water
Example of potential benefits
Introduction
CONCEPTS BIOPHYSICAL ANALYSIS
Tools and Information
Understand current water resources
Understand past water resources
Options for future- technical- socio-economic- policy oriented
TrendPast
Today
Future
• Observations• Remote Sensing• Analysis • Statistics
• Models
?
change
Quantification GWC
Water Demand?
Water Consumption?
Water Supply?
Impact Changes?
Productive Use?
Soil Water Conservation impact?
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
Physical detaillowhigh
Spat
ial s
cale
field
system
basin
continentPodiumSTREAMSLURPWSBMSWATWEAPIQQMSWAPAquaCrop
SWAT and WEAP
SWAT(Soil and Water Assessment Tool)
• Supply analysis
• Physical Based
• Impact soil-water-conservation measures
• Detailed farm management analysis
• Public domain• User friendly interface
WEAP(Water Evaluation And Planning systems)
• Demand analysis
• Conceptual based
• Benefit – Costs analysis
• Detailed upstream-downstream interactions
• 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
locally-sourced
non-RS
globalpublic-domain
RemoteSensing
Land Cover
StreamflowOperations
Climate
LAI
Soils
Topography
Socio-Economic
Groundwater
Data
Elevation
Landuse
SoilsClimate
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)
Results: Key Indicators
Inflow Masi
nga
Sedim
ent inflow M
asinga
Crop tr
ansp
iration
Soil e
vaporation
Groundwate
r rech
arge
Erosio
n
Scenario Land use* Year MCM/y Mton/y mm/y** mm/y** mm/y*** ton/ha/y***dry 931 1.0 335 121 16 1.2wet 2508 4.2 308 140 128 7.9dry 1.1% -21% 0% -1% 3% -23%wet 1.9% -21% 0% 0% 2% -18%dry 0.1% -1% 1% -5% 1% -2%wet 0.1% -1% 1% -4% 0% -1%dry 1.1% -10% 0% -1% 7% -12%wet 0.8% -7% 0% 0% 3% -6%dry 0.4% -21% 1% -1% 4% -23%wet 1.3% -20% 1% 0% 2% -18%dry 0.6% -11% 0% -1% 3% -14%wet 0.6% -10% 0% 0% 1% -10%dry 0.6% -8% 0% -1% 2% -8%wet 0.6% -6% 0% 0% 1% -5%dry 0.4% -6% 3% -12% 3% -9%wet 0.5% -6% 2% -12% 2% -8%dry 0.1% -4% 0% -3% 1% -4%wet 0.0% -2% 0% -2% 0% -6%dry 1.4% -18% 0% -1% 23% -21%wet 1.0% -12% 0% -1% 10% -12%dry 0.0% -5% 0% -1% 0% -5%wet 0.0% -4% 0% 0% 0% -4%dry 0.6% -7% 0% -3% 3% -8%wet 0.6% -6% 1% -2% 1% -5%
*M=Maize, C=Coffee, T=Tea,A=Agricul tura l ASAL, R=Rangelands;
** Agricultura l areas ; *** Bas in-wide;
Baseline
Inflow Masi
nga
Sedim
ent inflow M
asinga
Crop tr
ansp
iration
Soil e
vaporation
Groundwate
r rech
arge
Erosio
n
Scenario Land use* Year MCM/y Mton/y mm/y** mm/y** mm/y*** ton/ha/y***dry 931 1.0 335 121 16 1.2wet 2508 4.2 308 140 128 7.9dry 1.1% -21% 0% -1% 3% -23%wet 1.9% -21% 0% 0% 2% -18%dry 0.1% -1% 1% -5% 1% -2%wet 0.1% -1% 1% -4% 0% -1%dry 1.1% -10% 0% -1% 7% -12%wet 0.8% -7% 0% 0% 3% -6%dry 0.4% -21% 1% -1% 4% -23%wet 1.3% -20% 1% 0% 2% -18%dry 0.6% -11% 0% -1% 3% -14%wet 0.6% -10% 0% 0% 1% -10%dry 0.6% -8% 0% -1% 2% -8%wet 0.6% -6% 0% 0% 1% -5%dry 0.4% -6% 3% -12% 3% -9%wet 0.5% -6% 2% -12% 2% -8%dry 0.1% -4% 0% -3% 1% -4%wet 0.0% -2% 0% -2% 0% -6%dry 1.4% -18% 0% -1% 23% -21%wet 1.0% -12% 0% -1% 10% -12%dry 0.0% -5% 0% -1% 0% -5%wet 0.0% -4% 0% 0% 0% -4%dry 0.6% -7% 0% -3% 3% -8%wet 0.6% -6% 1% -2% 1% -5%
*M=Maize, C=Coffee, T=Tea,A=Agricul tural ASAL, R=Rangelands;
** Agricul tural areas; *** Bas in-wide;
11 Trash l ines
Baseline
1 Bench terraces
2 Conservation tillage
3 Contour tillage
4 Fanya Juu terraces and variations
5 Grass strips
6 Micro-catchments for planting fruit trees
7 Mulching
8 Rangelands
9 Ridging
10 Riverine protection
MCT
M
M
MCT
MCT
MCT
MCT
MCT
AR
M
MCTA
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
00_Base 01_Bench 02_ConsTill 03_ContTill 04_FanyaJuu 05_GrassStrips 06_MicroCatchments 07_Mulching 08_Rangelands 09_Ridging 10_Riverine 11_TrashLines
Unmet DemandAll Demand Sites (13), All months (12)
2005
Milli
on C
ubic
Met
er
0.0-0.5-1.0-1.5-2.0-2.5-3.0-3.5-4.0
-4.5-5.0-5.5-6.0-6.5-7.0
Results: Increase in hydropower
00_Base 01_Bench 02_ConsTill 03_ContTill 04_FanyaJuu 05_GrassStrips 06_MicroCatchments 07_Mulching 08_Rangelands 09_Ridging 10_Riverine 11_TrashLines
Hydropow er GenerationAll Reservoirs (9), All months (12)
2005
Thou
sand
Gig
ajou
le
180
160
140
120
100
80
60
40
20
0
Results: Increase in Benefits
Results: Benefit-Cost Analysis
• 20% of area ~ 100,000 smallholders
Benefits Costs mUS$/y ha 01_Bench 9.9 92,865 02_ConsTill 1.0 52,766 03_ContTill 4.9 52,766 04_FanyaJuu 9.0 92,865 05_GrassStrips 5.3 92,865 06_MicroCatch 1.6 1,000 07_Mulching 5.1 92,865 08_Rangelands 0.8 136,916 09_Ridging 8.9 52,766 10_Riverine 2.0 10,000 11_TrashLines 3.4 92,865
Costs Construction Maintenance
ha US$/ha US$/ha /y mUS$/y 92,865 100 20 2.8 52,766 0 0 0.0 52,766 0 0 0.0 92,865 200 20 3.7 92,865 50 20 2.3 1,000 500 20 0.1
92,865 0 0 0.0 136,916 50 0 0.7 52,766 100 20 1.6 10,000 100 20 0.3 92,865 50 20 2.3
B/C
mUS$/y mUS$ 2.8 7.1 0.0 1.0 0.0 4.9 3.7 5.3 2.3 3.0 0.1 1.5 0.0 5.1 0.7 0.1 1.6 7.3 0.3 1.7 2.3 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