The Green-to-Blue Water Continuum:An approach to improve agricultural systems’ resilience to water scarcityAlain Vidal, Barbara van Koppen, David Love & David BlakeCGIAR Challenge Program on Water and Food

An oldhistory of combinedrainfed and irrigated agricultureSinceancient times, the reality of water dependency has inspired farmers to innovateWater stored, mobilized and applied to plants in different ways, depending on the nature of the resource availableFarmers have alwaysdealtwith the green-to-blue water continuum to extract the best productive value - not only from crops, but fish, livestock, etc

A recenthistory of opposedrainfed and irrigated agriculturesSince the 60s, irrigation has almost doubled - from 160 to 300 Mha. Policies keep “poor” rainfed and “rich” irrigated agricultures separated, negating the green-to-blue water continuumNew irrigation farmers were historically ‘rainfed’ farmers, if not breeders or fishersAlmost half of today's irrigated surface is cultivated by farmers whose tradition is ‘rainfed’

Green-blue water in agricultureFrom Hoff & Rockström, SEI

Resilience conceptSociety and nature as truly inter-connected socio-ecological systemsNon-linear dynamicsThresholdsAlternate stable statesBasic continuity assumptionIrrigatedProductivityPERSISTENCE absorb shocks, while maintaining structure and functionADAPTABILITYability for learning, to cope with disturbanceTRANSFORMABILITYcapacity to reorganize, and create a new systemHumid rainfedDry rainfedGreen waterBlue waterFrom Hoff & Rockström, SEI

Non-linear dynamics

Thresholds

Alternate stable states

PERSISTENCE absorb shocks, while maintaining structure and function

ADAPTABILITYability for learning, to cope with disturbance

TRANSFORMABILITYcapacity to reorganize, and create a new system

Which is the right one?ResilientNon resilientResilientNon resilient

Opposed (thus, less) resilient agricultures Rainfed systems are less resilient for external reasonsGreen water is irregularly supplied and becomes scarcerLack of investment and markets for crop production Irrigated systems for internal reasonsIrrigated crops less resistant to drought resulting from irregular blue water supplyIrrigation may generate water excess that degrade soils and crop productivity

Green water is irregularly supplied and becomes scarcer

Lack of investment and markets for crop production

CPWF aims to increase water productivity and to ensure more equitable use of water amongst users and the environment

The green-to-blue water continuum…From David Molden, IWMI

…a way to reconcileopposed agricultures Increasing water productivity and improving farmers’ livelihoods should be done along the existing green-to-blue water continuum Could significant progress be achieved by learning from each others’ resilience?

Crossed lessonslearntfrom CPWF Green water dominated systemsIWRM research for mitigating drought and improving livelihoods within the Limpopo Basin (water scarce)Improving Mekong Water Allocation in the Nam Songkhram Basin (endangered wetland) Blue water dominated systemsMultiple Use water Systems (MUS) project in the (Andean, Nile,) Limpopo, Ganges and Mekong basins

Lessons learnt from IWRM project Green water is the source of runoff and percolation of blue water Ways to improve access to green water:In-field soil water conservation techniques that increase the rate of infiltration and percolation, e.g. mulching Micro‐catchment or runoff farming and supplementary irrigation to capture overland flow from areas adjacent to fields

How IWRM increases resilience Negotiation processes of users result in new institutions Resilience builds upon a multi-stakeholder approach and a combination of water management interventionsHousehold crop income raised from US$200 to 600 per yearIWRM in water scarce Southern AfricaProductivityResilience zoneGreen waterBlue water

Lessons learnt from Nam Songkhram BasinHighly contested waterscapeFloods and droughts always presented as main obstacles to development, whereas flood pulse is main driver of wetland productivityMultiple actors, in complex context and historyThreat of ‘Water Grid’ and other mega‐projects hangs over future of wetlands“paa boong paa thaam”

How is Paa Boong Paa Thaam more resilientthan « development » ?Highlydiversified on-farm and off-farm green water productive uses Household income US$1100/yRapid privatisation & land reform, coupled to continual pressure to build blue water control infrastructures, introduces disruptive changesCan PaaBoongPaaThaamsurvive transformation?Previous changes proved unsustainableWetlands in the Mekong basinWetland resilience zoneProductivityDisruptivechangeUnstable zoneGreen waterBlue water

Lessons learnt from MUS Multiple Use water Systems Multiple use water systems are an effective way to fightpoverty by improvingaccess to agricultural waterExperience shows that farmers use/re-use multiple (up to 9!) sources of water

Domestic water: An ignored form of blue waterHomestead-scale MUS gives high resilience against natural- and human-made volatilityEspecially for the poor and for women generates ‘more MDG per drop’Multiple-use water ladder, with household water-derived income ranging from US$40 to 300/yearCosts for multiple-use supplies for homestead-based production typically repaid within 3 years, from the income gained, therefore cross-subsidize domestic uses

How MUS increases resilience Ability to use multiple sources under various climatic conditions or as emergency provision, key for resilience Community-scale MUS allows building on what communities have been doing since time immemorial MUS - everywhereMUS resilience zoneProductivitySingle usesunstable zoneGreen waterBlue water

Multiple water uses, techniques and sources, together with resulting community organization do increase resilienceNeglecting the green-to-blue water continuum createsunaffordable disruptive changes Multiple use/sources resilienceProductivityDisruptiveChangeRainfed humidSingle usesunstable zoneRainfed dryGreen waterBlue waterResilience in the green-to-bluewater continuum: A synthesis

ThankyouAlain Vidal, CPWF Directora.vidal@cgiar.orgwww.waterandfood.org