1. Critical moments for adaptation in Asia; irrigation demand by crop linked to water supply by source
IPCC 2013
THERE ARE SUFFICIENT LAND AND WATER RESOURCES
to produce enough food by 2050,
BUT time specific management and allocation
strategies are needed
Good after noon, I am Qurat ul ain Ahmad from Pakistan, PhD student at VU university, Amsterdam funded by HI_AWARE project. Before the formal start of my presentation, I would like share IPCC 2013 finding which states: world has SUFFICIENT LAND AND WATER RESOURCES to produce enough food by 2050, but timely action is required to cope with these challenges. As session is also concerned with fresh water availability and access so resources are there but collaborative and integrated adaptation approach is required to have sustainable future.
Qurat-ul-Ain Ahmad
Biemans. H, Siderius. C, Moors. E
Contact:
Theme: Fresh water availability and access

2. Critical Moments (CMs)
Times of the year when climate risks are highest and when specific adaptation interventions are most effective
e.g. Water for agriculture
Supply < Demand = Stress*
Critical periods: times of the year when specific climate risks are highest and when specific adaptation interventions are most effective. e.g. as we know that agriculture is the main consumer of fresh water and during different crop growth stages certain amount of water is required, and if
S < D = Stress on water. This stress could be due to many reasons like alteration of climate trends, early melting of snow/ glaciers and peak shifts, monsoon onset alterations, Higher temperatures ets. Other factors also responsible for water stress are …
* J. Jagermeyr et al 2015

3. Challenges Water use vs supply, uncovered gar of 40% by 2030
* Challenges Research Question Methodology Results Conclusion
Challenges
Water use vs supply, uncovered gar of 40% by 2030
Here I would like to draw your attention to the main challenges caused by CC and rapidly growing world population on water availability and food production. Agriculture used >70 % of total fresh water but ~ 50 % of water used is lost in evaporation and conveyance losses. Similarly large part of water extracted for domestic and industries remained unused and hence wasted. And it is projected that if water us pattern remains same then by 2030 water gap between use and supply will increase up to 40%. This is quite alarming situation. And when we talk about the more water scarce region in the world, then Asian countries are reported and projected as highly water scare region. This water scarcity is due to more rising global temperatures, more frequently occurrence of weather extremes, high rate of population rise, poor water management practices. And under these challenges, when we project future food production, then again Asia is highly vulnerable. Keeping in view the above mentioned challenges.

4. What are the impacts of seasonal variations on crop production
Challenges * Research Question Methodology Results Conclusion
Research Questions
What are the impacts of seasonal variations on crop production
How to quantify the adaptation measures for agriculture production during CMs
Critical periods: times of the year when specific climate risks are highest and when specific adaptation interventions are most effective
Adaptation Turning Points (ATPs): when current policies and management practices are no longer effective and alternative strategies have to be considered
Factors which have direct or indirect role in triggering CM/Stress for water availability and crops yield
Increased temperatures decreases the soil moisture and increases the crop irrigation water demand
Increased temperature reduces the growing season length hence the quality and yield of food
Climate and weather induced variables are the main driver of weather extremes (pressure gradients, wind etc.)
CM could be summer months (April-May) when less surface water is available and more pressure on ground water extraction.
Assess contribution of crops in total food production which are responsible for irrigation water during weather stress situation
Long term past analysis of hydro-meteorological data can be helpful in assessing the time of occurrence of water cycle variability or shortage
Assessment of seasonal and sub seasonal water patterns, availability and supply is helpful in identifying weather stress related hazard

5. HKH Study Area
For this research, Indus, Ganges and Brahmaputra River basins (HKH) have been selected as study areas. HKH is third largest frozen water reservoir in the world and known as Asia water tower. Summer monsoon is the dominating climatological system in East Asia, melt water from snow/ glaciers is major contributor in river flows regulating hydro – ecological systems in the region. Agrarian economy of SA region homes about 25 % of world population.

6. Method: Model Structure
Challenges Research Question * Methodology Results Conclusion
Method: Model Structure
Input Processes Output
Climate parameters
(Temp, Precipitation and Radiation)
Soil & land use data
CO2, country specific efficiencies
Bio-Physical processes
Phenology, AET Interception, Soil water & Temperature, Irrigation water, Photo synthesis
Potential / actual crop and grass yield/ production
Crop irrigation water demand
Irrigation water consumption
Rain water consumption
To estimate seasonal irrigation water demand and food production in the study area, LPJmL model has been used. LPJmL is a grid based model run at 0.5 degree resolution at a daily time step. LPJmL develops physical link between water and carbon cycle and establish relationship between water availability and food production under climate change. No of input parameters are required by model to perform bio-physical processes and in result we obtained no of output. For this research, we were interested in potential and actual crop yield, irrigation water demand and consumption and rain water consumption.
Lund-Potsdam-Jena managed Land (LPJmL) dynamical global hydrological - Vegetation model
Biemans et al., 2013, Jagermeyr et al., 2015

7. Monsoon onset dependent planting dates in South Asia
In this study we introduces multi cropping seasonal estimates of water demand by crops. For this we distinguish two main cropping season Kharif (June – October) and Rabi (November – March) and adjusted crop planting dates as per Monsoon onset. In SA monsoon onset dates are determined by IMD. MS onset in India (kerala) starts around 01 june (152 JD) and arrives in Pakistan around mid July (197 JD). For model simulation, planting dates in Kharif were set at least 5 days after monsoon onset because several days of rain are required before planting and 01 November is adjusted as sowing date for Rabi crops. Plants phenology depends on the appropriate selection of sowing dates. Crops growth and yield depends on the choice of dates considering water availability and climatic conditions ahead during crop growth stages. Also use of accurate plants sowing dates make more effective use of rainfall during kharif season.
Biemans et al., 2015

8. Challenges Research Question Methodology * Results Conclusion
Net (consumption) vs. gross (withdrawal) irrigation water demand in billion m3 for South Asian countries
In this slide, we have estimated net and gross irrigation water in billion cubic meters (BCM) for individual countries (India, Pakistan, Nepal and Bangladesh) and South Asia as a whole. Indi and Pakistan both have largest Irrigation water demand in region. In Pakistan irrigation water demand is almost equally divided over kharif and rabi season whereas, in India approximately ¾ of its irrigation water is demanded in Rabi dry season. Seasonal distribution of IWD is a results of rainfall patterns in the region. Ground water irrigation is calculated = demand – available surface water supply, therefore more ground water is required during dry winter season when less surface water is left in river. NID (consumption: the minimum amount of additional water needed to fill the soil to field capacity and the amount needed to fulfil the atmospheric evaporative demand) is almost half of GID (withdrawal: accounts for application and conveyance losses, and is calculated by multiplying the net irrigation water demand with a country-specific efficiency factor, which is different for surface-water irrigation (~ 30%) and groundwater irrigation (~ 70%). Half of withdrawal water is lost and major part of irrigation water supply is contributed by ground water extraction which has higher irrigation efficiency n hence crop production is also higher from rabi crops. Seasonal distribution of IWD is a result of rainfall patterns in region. Ground water is modelled = D- SW Availability.

9. Seasonal irrigation water demand patterns (varying climatology and water availability)
We have observed that due to varying climatological conditions and availability of spring and summer runoff from snow and glaciers, cropping patterns and hence seasonal patterns of irrigation water demand differs sharply between region and seasons. The Indus basin shows relatively stable irrigation water demand through out the year. Whereas Ganges basin in India shows more seasonality in kharif and rabi seasons. Very less irrigation water in required during monsoon season, when rainfall is sufficient and large part of irrigation water is required during winter season with less surface water and almost no rain fall. Same pattern is even more strong in Brahmaputra basin.

10. Net irrigation water demand by sources
Indus
Ganges
Brahmaputra
Net irrigation water demand (bcm)
We have also observed that seasonal irrigation water demand differs sharply both in terms of source and magnitude. E.g. in Indus, irrigation water demand is primarily fed by melt runoff in Kharif season and by ground water in winter. Whereas in India, more seasonality is pronounced and monsoon water is sufficient in kharif season and winter irrigation water demand is made by GW extraction. Same pattern is even more strong in Brahmaputra basin.
(Annual cyle of IRWD in term of temporal estimation…)

11. Crop specific periods of peak water demand forming Critical Moments
Net irrigation water demand (bcm)/ day
Rabi
Summer
Kharif
Indus
Ganges
Brahmaputra
Net irrigation water demand (bcm)
In this slide first we have estimated mean annual cycle of peak irrigation water demand per crops and find out that single peak of net water is demanded by wheat crop in winter season while two peaks of water are required by rice crops one in winter and one in kharif. This is the reason why more irrigation water is required during rabi season and to fulfill irrigation water demand, huge amount if water is extracted from ground reservoirs. After we have compared this peak water demand times with irrigation water availability from different sources, and identifies possible critical moments. E.g. if we focus on peak water demand time of rice crop during kharif season, sufficient rain water is available in the river but due to altering pattern of monsoon onset or some weather extremes, crops could face water shortage along with devastating affect of heat waves and dry spell during crop growth sensitive stages and crop production could destroyed.

12. Reduction in crop production if irrigation water is absent
Irrigated food production
Food production loss
In this slide, we have estimated seasonal crop production by different water sources. Blue and green colors shows irrigated and rainfed crops production in kharif and rabi season respectively for (sum of wheat, rice, maize, tropical cereals and pulses) in South Asia (India, Pakistan, Nepal and Bangladesh) and individual river basins. Light blue corresponds to potential rainfed production on irrigated land, i.e. dark blue corresponds to the increase in production due to irrigation. In SA 50 % of the total food production in kharif and 95 % in rabi is supported by irrigation. Due to absence of irrigation water in SA, food production reduced by 15 % in kharif and 60 % in rabi respectively. So it is important to adopt appropriate irrigation options to improve water productivity to retain food production under changing climatic conditions.

13. Future work
Improve spatial and temporal representation of crop specific seasonal pattern of irrigation water demand
Implementation of different irrigation techniques (surface, sprinkler and drip) to estimate water use productivity in different seasons
Impacts of weather extremes on water availability and hence on food production during CMs

14. Challenges Research Question Methodology Results * Conclusions
Seasonal estimates of crops water demand are lower than previous studies (annual vs season)
Crop specific peak water demand occurs at different moments requiring water from different sources
Crop irrigation water demand differs sharply between seasons and regions
Critical moments of adaptations are e.g. Kharif (June – Sept.) because of uncertainty in rain and timing of melt water for rice crop in South Asia

15. Supported by the UK’s Department for International Development (DFID) and Canada’s International Development Research Centre (IDRC)