water resources conditions and possible savings in irrigation systems prof wim bastiaanssen
TRANSCRIPT
Which tools are available to assist planning ?
Cheema – Ph.D. student TU-Delft
Remote sensingWater basin models
Groundwater flow modelsClimate models
Water accountingGIS data
Smart phoneSMS messages
Yesterday
Models are Required for Future Projection
PAST FUTURE
FUTURE: C
FUTURE: A
Policies:A, B, C
ObservationsRemote Sensing Simulation Models
FUTURE: B
Yesterday
Cheema – Ph.D. student TU-Delft
Conclusions day 1• The basic data needed for planning is
obsolete. Tools can assist with the derivation of real time and localized data
• The impact of certain interventions need to be understood, i.e. scenario analysis
• Water resources planning is a political process• More attention should be given to convert
information into evidence based decision making: data alone is not sufficient
From information to planning
Data
database
Ministries & AgenciesTargets
DefineScenarios
Tools
Impact &Advice
Parlement decisions
(Technical component only)
Fluctuation of the renewable water resources ?
Cheema – Ph.D. student TU-Delft
Yearly RainfallTRMMSatellite1998 to 2012
Modelling Recharge and Runoff for period 2000-2009 (SPHY model)
This are the renewable water resources
Cheema – Ph.D. student TU-Delft
• Integrate satellite data and ground stations• Downscale and calibrate local rainfall (250 m)• Compute actual evapotranspiration (250 m)• Validate evapotranspiration where feasible• Make water accounts for each basin• Assess renewable water resources• Determine degree of over-exploitation
How to improve the knowledge on renewable water recourses ?
Can we reduce the water demand for irrigation ?
Cheema – Ph.D. student TU-Delft
• Reduce abstractions of groundwater- Quota on water use, well licenses, stop subsidized diesel for pumps- Reduce crop ET by improved irrigation technologies- Reuse urban, industrial and irrigation water• Control agricultural areas- Control irrigated area (ha)- Control cropping intensity- Abandon certain crops - Land retirement• Enhance rainfed agriculture- New seeds- Better practices• ……
TRMM validation over PakistanIrrigation efficiency of 40 %
1000
400
500 350
300 450
Net withdrawal is 1000 – 750 = 250 mm
TRMM validation over PakistanIrrigation efficiency of 80 %
1000
800
500 350
140 210
Net withdrawal is 1000 – 350 = 650 mm, incremental ET is 400 mm
Control
your ET !
How to reduce crop evapotranspiration (ET) ?
Cheema – Ph.D. student TU-Delft
• Use drought tolerant crop varieties• Short duration crop varieties• Apply mulching of row crops and tree crops• Manage soil moisture within a preferred regime • Introduce drip systems that reduced soil evaporation • Apply a certain level of deficit irrigation that does not affect crop production
Impose a certain level of water stress
Cheema – Ph.D. student TU-Delft
Actual ET Potential ET
Water
stress
For every water basin:
• Improve the knowledge of renewable water resources, and the intra-annual fluctuations
• Assess the level of over-exploitation and estimate the reduction need
• Reduce irrigation water demand by ET reduction measures (mm) and areal control (ha)
• Focus on areas where recharge fulfills > 100 mm/yr• Make water accounts current & future• Define scenario’s and interventions• Evaluate impact of scenario’s • Advice Members of Parlement
Thank you !