Based on water balance, it was developed from the perspective of irrigation within a river basin framework, but can be applied across sectors. Three main scales are– the basin, service level, and field scale. provides information to 1- Identify opportunities for saving water and increasing water productivity2- Conceptualize and test interventions in the context of multiple uses of water3- Develop effective strategies for allocating water among different users4- Assess the scope for the development of additional water resources
1- Some definitions that are quite specific at irrigation service level seem to be generic at basin scale, while others do not provide adequate information. For instance, process consumption at irrigation service scale represent only crops evapotranspiration while at basin scale it includes irrigated and rainfed crops, municipal and industries, fisheries, forestry, dedicated wetlands and all other intended uses. Therefore, parts of the information that are important in a basin context are not covered in the framework, such as separating figures for water consumption by rainfed crops and irrigated crops. 3- the link between land use and water use is not addressed, which leads to missing some important information in regard with water use and availability. For example rainfall on many land uses classes is not available for water resources planning. Instead the rainfall surplus (P-ET) is potentially utilizable.
The ET of “conserved land use” relates to the ET of national parks, wetland, tropical rainforest etc. These natural ecosystems should not be modified without having very strong incentives and arguments. The land use category “utilized land use” relates to a low to moderate resource utilization, such as savannah, woodland and mixed pastures. The returns from ‘utilized land use” is often limited to livestock, wildlife and fuelwoods, and the anthropogenic influence is limited. “Modified land use” relates to the replacement of the original vegetation for increased utilization of land resources. Examples are rainfed plantation forests, rainfed crops and rainfed pasture. Water diversions and abstractions do not take place in “modified land use”, but the ET process differ from the original ET patterns, and stream flow is altered. The category “managed water use” represent landscape elements that receive withdrawals from the blue water system by constructed infrastructure. This relates to water withdrawals for irrigation, aquaculture, domestic use and industries, among others. These flows are often discussed when securing the domestic water supply and meeting the millennium development goals. Obviously, this is only a fraction of the total water use picture.
Impact of alternative future scenario’s on WA+ indicators aiming at zero-overexploitation (storage change fraction) and increase food security (land productivity)
Water accounting plus (WA+): A tool for basin-wide water accounting using remote sensing data
www.iwmi.orgWater for a food-secure worldWater Accounting Plus (WA+): A toolfor basin-wide water accounting usingremote sensing dataPoolad KarimiMay 2013, Bonn
www.iwmi.orgWater for a food-secure worldWater Accounting• Policy makers:– Accountability of water managers• Water managers:– Quick overview of current status of all water issues• Water planners:– Impact of changes (climate, land cover)– Effectiveness of adaptation• Donors– Impact assessment• Water users:– Overall picture
www.iwmi.orgWater for a food-secure worldWater Accounting Methods• SEEAW– United Nations Statistics Division: System of Environmental-Economic Accounting for Water• AWAS– Australian Water Accounting Standard• WAFNE- UNEP’s Water Footprint, Neutrality, and Efficiency project• ABS Water accounts (Australian Bureau of Statistics)
www.iwmi.orgWater for a food-secure worldExisting issues• Too complex• Results of some of these frameworks are far too complex to beused as supporting tool for decision making.• Lacking input• Input requirements are often not available or are based on long-term expensive monitoring activities.• Only abstracted water• In many areas only a small fraction of the entire water resourcesand water use is actually abstracted.• Location specific• Most frameworks are location specific rather than universalapplicable.• No intervention options• Most frameworks present results without a differentiation betweenmanaged, manageable and non-manageable water flows.
www.iwmi.orgWater for a food-secure worldIWMI WA
www.iwmi.orgWater for a food-secure worldIWMI WAIWMI Research Report - 49IWMI SWIM Paper - 1Molden, D. 1997. Accountingfor water use andproductivity. Colombo, SriLanka: InternationalIrrigation ManagementInstitute.Molden, D.; Sakthivadivel, R.; Habib, Z.2001. Basin-level use and productivity ofwater: Examples from South Asia.Colombo, SriLanka: IWMI.
www.iwmi.orgWater for a food-secure worldIWMI WA limitationsMain limitations:• Some definitions are generic at basinscale; e.g. Process depletion• Does not differentiate which water sourcesgo to each use (e.g. How much ET comesfrom rain versus irrigation)• Link between land use and water use isnot addressed
www.iwmi.orgWater for a food-secure worldWater Accounting +• Separation among managed, manageable,and non-manageable flows• Separation of consumed water (ET) totranspiration, evaporation and interception• Relate depletion to land use classes• Redefine available water resources• Amenable to remote sensing analysis
www.iwmi.orgWater for a food-secure worldWA+ Land classificationsLand type classifications in WA+Land type Land useNon-manageable Conserved land use National parks, tropical rainforest,wetlands, lakes, etcManageable Utilized land use Forests, Savannas, deserts,mountains, etcManagedModified land use Rainfed crops, Plantation trees,rainfed pastures, etcManaged water use Irrigated crops, industrial anddomestic uses
www.iwmi.orgWater for a food-secure worldMain Required data- Precipitation- Landuse Landcover map- ET map- Biomass production- Storage changeAccounting sheets4 sheets:- Resource base sheet- Evapotranspiration sheet- Productivity sheet- Withdrawals sheetWA+
www.iwmi.orgWater for a food-secure worldResource base sheetIndicators DefinitionExploitable water fraction Explitable water divded by the net inflowStorage change fraction Fresh water storage change divided by exploitable waterAvailable water fraction Available water divided by exploitable waterBasin closure fraction Utilized flow divided by available waterReserved flow fraction Reserved outflows divided by the total outflow
www.iwmi.orgWater for a food-secure worldIndicators DefinitionT fraction Total T divided by the total ETBeneficial fraction Beneficial E and T divided by the total ETManaged fraction Managed ET divided by the total ETAgri. ET fraction Agricultural ET divided by the total ETIrri. ET fraction Irrigated agricultural ET divided by the agricultural ETEvapotranspiration sheet
www.iwmi.orgWater for a food-secure worldIndicators DefinitionLand productivity crops Crop biomass times harvest index divided by cropped areaLand productivity pastures Pastures biomass times harvest index divided by pasture areaWater productivity crops rainfed Rainfed crops biomass times harvest index divided by rainfed crops ETWater productivity crops irrigated Irrigated crops biomass times harvest index divided by Irrigated crops ETFood Irri. Dependency Irrigated food production divided by total food productionProductivity sheet
www.iwmi.orgWater for a food-secure worldIndicators DefinitionGW withdrawal fraction Groundwater withdrawals divided by total withdrawalsClassical irrigation efficiency Incremental ET of agriculture divided by withdrawals for agricultureRecoverable fraction Return flow divided by total withdrawalsWithdrawals sheet
www.iwmi.orgWater for a food-secure worldNile Basin
www.iwmi.orgWater for a food-secure worldInput RS data
www.iwmi.orgWater for a food-secure worldResource base sheet Nile Basin 2007All components are in km3
www.iwmi.orgWater for a food-secure worldEvapotranspiration sheet Nile Basin 2007All components are in km3
www.iwmi.orgWater for a food-secure worldProductivity sheet Nile Basin 2007
www.iwmi.orgWater for a food-secure worldIndus Basin
www.iwmi.orgWater for a food-secure worldInput RS data
www.iwmi.orgWater for a food-secure worldResource base sheet Indus Basin 2007All components are in km3
www.iwmi.orgWater for a food-secure worldEvapotranspiration sheet Indus Basin 2007All components are in km3
www.iwmi.orgWater for a food-secure worldProductivity sheet Indus Basin 2007
www.iwmi.orgWater for a food-secure worldWithdrawals sheet Indus Basin 2007All components are in km3
www.iwmi.orgWater for a food-secure worldScenario Action Real watersavingWA+ indicators(km3/yr)AMixed actionsReduce E rainfed land by 5 %Reduce E irrigated land by 15 %Reduce irrigated area by 0 %Biomass production increase 5 %Harvest index increase 5%Reduce utilizable flow by 50%12.6 Storage change fr.: -0.17Reserved flow fr.: 0.73T fr.: 0.48Beneficial fr.: 0.53Land productivity irri: 8,560Land productivity rainfed: 1,030Water productivity irri: 0.90GW withdrawal fr.: 0.41BReduce EReduce E rainfed land by 15 %Reduce E irrigated land by 35 %Reduce irrigated area by 0 %Biomass production increase 5 %Harvest index increase 10%Reduce utilizable flow by 75%37.8 Storage change fr.: -0.02Reserved flow fr.: 0.85T fr.: 0.50Beneficial fr.: 0.55Land productivity irri: 9,300Land productivity rainfed: 1,130Water productivityirri:1.09GW withdrawal fr.: 0.32CModify areaReduce E rainfed land by 5 %Reduce E irrigated land by 15 %Reduce irrigated area by 15 %Biomass production increase 5 %Harvest index increase 10%Reduce non-utilizable flow by 75%39.4 Storage change fr.: -0.01Reserved flow fr.: 0.85T fr.: 0.45Beneficial fr.: 0.50Land productivity irri: 9,300Land productivity rainfed: 1,130Water productivity yirri: 0.93GW withdrawal fr.: 0.30Impact of example future scenario’s on WA+ indicators for Indus Basin
www.iwmi.orgWater for a food-secure worldImpact of scenario B on WA+ resource base sheet for the Indus (km3)All components are in km3
www.iwmi.orgWater for a food-secure worldThanksReferences:Karimi, P., Bastiaanssen, W. G. M., & Molden, D. (2012). Water Accounting Plus (WA+) – a water accounting procedurefor complex river basins based on satellite measurements, Hydrol. Earth Syst. Sci. Discuss., 9, 12879-12919,doi:10.5194/hessd-9-12879-2012.Karimi, P., Bastiaanssen, W. G. M., Molden, D., and Cheema, M. J. M. (2012). Basin-wide water accounting usingremote sensing data: the case of transboundary Indus Basin, Hydrol. Earth Syst. Sci. Discuss., 9, 12921-12958,doi:10.5194/hessd-9-12921-2012.Karimi, P., Molden, D., Bastiaanssen, W. G. M., Cai, X. 2012. Water accounting to assess use and productivity of water:evolution of a concept and new frontiers. In Water Accounting: International Approaches to Policy and Decision-Making, edited by J. M. Godfrey and K. Chalmers, pp. 76–88, Edward Elgar Publishing. UK.Contact: firstname.lastname@example.org