6 3 ghazi alam - assessment of impacts of water transfers to urban-industrial sectors- updated 12-27
Assessment of the impacts of watertransfers to urban-industrial sectors on irrigation outcomes in the Indus Basin Y. C. Ethan Yang1, Ghazi Alam2 & Claudia Ringler3 1/U of Massachusetts, 2/Cornell U./NESPAK, 3/ IFPRI
Urban-industrial water use Urban-industrial water use in Pakistan is currently almost entirely met by groundwater (GW) sources Given the rapid increase in urban-industrial water demand in recent years and projected out into the future, there is a high risk that GW tables in major cities might become saline, requiring rural-to-urban water transfers This paper assesses the implications on agricultural production
Modeling- Data used (1) This study modified the Indus River Basin Model Revised (IBMR) to evaluate the effect of transferring irrigated water to domestic and industrial (D&I) water use The IBMR in its most recent revision is significantly different, from its original version that was developed in the 1970s, having undergone several revisions over the past three decades.
Modeling- Data used (1) Utilizing Non-linear programming techniques and advancements in computing power, the IBMR in its current form gives a fairly accurate description of the Indus Basin Agricultural and Hydrologic System. D&I water uses in nine major cities located in Pakistan are considered in the modeling framework Utility function of D&I water uses are derived from water demand curve (based on historical water demand-price relationship) for both domestic and industrial water
Modeling- Data used (1) Surface water is assumed to be diverted from the closest irrigated canal Groundwater is assumed to be unlimited Canals Cities 02-CBD Lahore 04-UC Gujranwala 11-JHA Faisalabad 17-SID Multan 22-USW Rawalpindi Islamabad 25-KAB Peshawar 39-ROH Hyderabad 42-KAL Karachi
Modeling- Data used (1) Water demand (Sutton 2009) Major Industry Water demand group (MAF)Textile 1.103Chemical 0.167Paper 0.085Food 0.078 Industrial production (CMI 2005-06 survey) BALOCHI ISLAM Group PAKISTAN PUNJAB SINDH NWFP STAN ABADTextile 1328 764 447 74 42 1Chemical 493 213 167 69 28 16Paper 133 71 29 27 4 2Food 1861 1122 556 118 36 29
Domestic-Industrial water transfers Two different scenarios: S 1: No cap for groundwater pumping but pumping cost will increase with groundwater depth S 2: Cap total groundwater pumping at 50 MAF (safe yield for the system) and pumping cost will increase with groundwater depth Note: The Safe Yield may be adjusted to any figure in the IBMR, it is the entirely the modeler’s choice.
Dom&Ind transfers—water diversions (S1) Surface water GroundwaterOptimized combinations of GW and SW resources
Dom&Ind transfers—decline in water table (ft) (S1)Change in depth to water table: Punjab most affected
Dom&Ind water transfers—crop profit (S1)Slight reduction from dom&ind competition, decline inbenefit from increasing pumping cost as GW tablescontinue to decline
Dom&Ind water transfers—change in crop profits (S1) (in percent)0.30.20.1 0-0.1-0.2-0.3-0.4 GW pumping increases by 7%. Crop production decline by 0.01%.
Dom&Ind water transfers—crop profit (S2)Larger decline in total and crop benefits when GW islimited.
Dom&Ind water transfers—total benefits (S2In drought years, industrial production declines due towater scarcity.
Dom&Ind water transfers—change in crop profits (S2) (in percent)1510 5 0 -5-10-15-20 GW pumping decline by 14%. Crop production decline by 5.2%.
Impacts of D&I transfer on provincial irrigation profitsCrop benefit change Scenario Scenario (%) 1 2 Punjab -0.94 -1.82 Sindh -0.29 -0.74 Others* 4.86 8.24 *Others shows benefits, but production is low.
Conclusions Using only surface water for D&I uses is insufficient when Water Accord is enforced (results not shown) When groundwater is unlimited, the impact on crop profits is small, but the water table (especially in Punjab) would drop dramatically If total groundwater pumping is capped at safe yield, crop profit will decrease 5.2% In very dry years, industrial output is affected by water scarcity
Conclusions Major crop productions such as: basmati and irrigated rice, wheat and sugarcane will suffer larger impacts Groundwater tables will continue to decline (and will do so even more with continued population increase) D&I transfers reduce crop profits particularly in Punjab, followed by Sindh, while other provinces show slight improvements
Policy recommendations GW tables likely to continually decline, salinization will increase and urban GW sources are threatened Rural-to-urban water transfers common in many water-scarce countries and likely to occur in Pakistan as well Food production impacts depend on the specific canals from which water is transferred to urban/industrial areas can study alternatives
Policy recommendations Impacts on rural incomes will depend on how and if farmers are compensated for the rural-to- urban water transfers Irrigation sustainability will depend on irrigation service providers being able to charge urban/industrial consumers Given scarce/fragile GW resources in parts of Pakistan, important to more efficiently use SW resources (additional ongoing research with the Punjab Irrigation Department)