The last version of Indus Basin Model Revised (IBMR) is based on data from 2000 (primarily the Agricultural Statistics of Pakistan and water-related data from the Water and Power Development Authority [WAPDA]) and earlier farm surveys (for example, 1976 XAES Survey of Irrigation Agriculture and the Farm Re-Survey in 1988 as part of the Water Sector Investment Planning Study [WSIPS])

Alford, Donald

Brown, Casey

Debowicz, Dario

Robinson, Sherman

Savitsky, Andre

Wescoat, James

Yang, Yi-Chen

Yu, Winston

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   155 The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6 The last version of Indus Basin Model Revised (IBMR) is based on data from 2000 (primarily the Agricultural Statistics of Pakistan and water-related data from the Water and Power Development Authority [WAPDA]) and earlier farm surveys (for example, 1976 XAES Survey of Irrigation Agriculture and the Farm Re-Survey in 1988 as part of the Water Sector Investment Planning Study [WSIPS]).Model Structure Change: The Lateral Groundwater Flow in IBMRAlmost every aspect of hydrogeology is considered in the original IBMR  structure except for lateral flow. In this study, this lateral flow was defined as the under-ground flow in or out of an agro-climatic zone (ACZ) due to the  groundwater hydrologic gradient. Since there was no basic survey data available, this value is estimated.Assuming that the lateral flow has a linear relationship with the change in water table, the following equation is considered: Dlateral = kd2 × (∆GD – kd1) (B.1)where Dlateral is the lateral flow, ∆GD is the monthly water table change, and kd1 and kd2 are coefficients. A pre-defined IBMR simulation was set up to  solve for kd1 and kd2 for each ACZ. The purpose of this predefined simula-tion is to search for a set of kd1 and kd2 for  different ACZs and groundwater types that makes the groundwater depth at the end of the simulation match the long-term observed value. This procedure means that the lateral flow should balance the water flow in and out of the aquifer. Since the groundwa-ter balance is a post-calculation after the optimization in the current struc-ture, all of the economic outcomes from IBMR will not be affected by adding kd1 and kd2.A p p e n d I x  BIBMR Updating to IBMR 2008156 IBMR Updating to IBMR 2008The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6Model Structure Change: The Refined Sugar and Sugar Cane IssueIn the original IBMR (Ahmad, Brooke, and Kutcher 1990), sugarcane will  produce two different end products: SC-GUR, which is treated as refined sugar and consumed at the farm level, and SC-MILL, which is the production of sug-arcane that goes into the market. SC-MILL was redefined in IBMR and the refined sugar demand for the Indus River was modeled. This section describes the details of this modification.Using the Pakistan Sugar Annual 2009 Gain Report (USDA 2009), the basin-wide production, demand, and price of both sugarcane and refined sugar are available. The model uses the price and demand of refined sugar to build the demand  function in IBMR. Therefore, when the model optimizes the produc-tion, it will optimize the refined sugar production. However, the cropped area and the straw yield should be computed from sugarcane. A conversion coeffi-cient between refined sugar and sugarcane is used to achieve this purpose. The value used in the model is 0.0865, which is described in Ahmad, Brooke, and Kutcher (1990) and is also similar to the value reported by the USDA (2009). The relationship between  sugarcane and refined sugar production (unit as weight) is: Refined Sugar = 0.0865 × Sugarcane (B.2)This coefficient is used to adjust the yield from sugarcane to refined sugar both as the unit of weight per area of land and also the straw conversion coef-ficient for SC-MILL. Meanwhile, since the model computes refined sugar production, SC-MILL was added as one of the consumable crops. The on-farm consumption ratio of refined sugar mentioned in Ahmad, Brooke, and Kutcher (1990) was used as the refined sugar demand for 2008–09.Model Structure Change: Removed Variables and equations in IBMR 2008The tractor and private tubewell numbers in the model are considered appro-priate, so further investment in tractors and private tubewells is not necessary and was therefore removed from the model. The related constraints are also removed. Draft power is 99 percent provided by tractors in Pakistan. Therefore, the provision for draft power from bullocks is removed from the model. The removal of the bullock requirement is problematic, since it is one of the meat sources in the model. The fixed-cost of bullock is much higher than cow. Under this circumstance, bullock will never be raised. Therefore, the bullocks-cow population constraint is changed to force the model to maintain a certain amount of bullocks in each ACZ. In addition, one item is added to describe the tractor cost by multiplying the price of tractor per hour per acre with the tractor power requirement of different crops, months, and ACZs.IBMR Updating to IBMR 2008 157The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6 data UpdatingPrice UpdateThe crop prices from the “Agricultural Statistics of Pakistan (ASP) 2008–2009” (Government of Pakistan, Ministry of Food, Agriculture and Livestock 2010) are collected by region. A simple mapping check was first conducted to assign the ACZs in IBMR into the nearest region. The ratio from 2000 and 2008 ASP prices is used to update the crop price data for IBMR. The livestock prices (milk and meat) are updated with a similar procedure. Wages, protein cost, tractor cost, tubewell cost, seed cost, water cost and all other miscellaneous cost are updated based on the change in gross domestic product (GDP). A rate of 1.51 is used to update all the mentioned prices for IBMR.Demand UpdateThe demand data are used to construct the demand curves in IBMR. Since the crop price has been updated, the demand should also be updated, based on the assumption that the slope of the demand curve will remain the same in 2000 and 2008. The new demands are then back calculated by fixing the slope of demand curve with the given 2008 price.On-Farm Consumption UpdateThe on-farm consumption should also be updated for the new baseline. According to Ahmad, Brooke, and Kutcher (1990), the values of on-farm  consumption are computed by multiplying the data in estimated total  production by the propor-tions of produce consumed on the farm from the re-survey. Following this con-cept, an updated total production table for 2008 is computed first using data in the 2008 ASP. The on-farm consumption ratio is assumed to remain the same from 2000 to 2008. Using the same ratio the on-farm consumption is updated at ACZ level.Yield UpdateThe observed crop yield data from the 2008 ASP were used to compare the 2000 observed yield with the IBMR 2000  baseline. Most of the crops have similar values allowing the national crop yields to be directly updated to IBMR baseline using ASP 2008 values. However, some crops—cotton, gram, orchard, and  fodder—have either larger differences or have no data for updating. Therefore, the cotton yield (seed cotton) for the IBMR baseline is updated using Food and Agricultural Organization of the United Nations data. And for all other missing crops, yields are calculated using the average ratio of 2008/2000 ASP crop yields multiplied by the IBMR 2000 baseline crop yield values.IBMR Model diagnosisSince IBMR is an optimization model, the results cannot be expected to match uniquely the observed values. Therefore, we do not try to validate the model with observation but rather diagnose the model to check if the crop production and area shows a similar pattern as the observed. The purpose is to understand the 158 IBMR Updating to IBMR 2008The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6 performance of the model under baseline conditions as well as the difference between observations and the baseline. The primary outputs of IBMR are  agricultural products; therefore, the factors checked are cropped area, crop  production, and livestock production.The observation data are all summarized from the 2008–09 ASP, and the comparisons have been done at the provincial level. Punjab and Sindh are two major provinces that rely on the irrigated network from the Indus River. The IBMR shows better results in the cropped area and production for these two provinces, as shown in figures B.1 and B.2. Almost all crops are at the same Onion03,0006,0009,00012,00015,00018,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoChiliCropped area (acres, thousands)a. Cropped area05,00010,00015,00020,00025,00030,00035,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliProduction (tons, thousands)b. Crop productionIBMRASP 2008–09Figure B.1 Cropped Area and production from IBMR Baseline and ASp 2008–09 in punjabNote: IBMR = Indus Basin Model Revised, ASP = Agricultural Statistics of Pakistan.IBMR Updating to IBMR 2008 159The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6 magnitude for the modeling result and the observation except for SC-MILL. In IBMR, we used the parameters (price, yield and  consumption) of refined sugar to model this commodity. A possible reason for the underestimation might be due to the price underestimate and also  government subsidies on sugarcane. The R2 for cropped areas are 0.98 and 0.98 for Punjab and Sindh, respectively. And the R2 for  production are 0.99 and 0.99 for Punjab and Sindh, respectively. These results show that the model captures the trend of cropped area and production very well. Although the absolute  values might be different, the relative cropped 01,0002,0003,0004,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliCropped area (acres, thousands)a. Cropped area, IBMR baseline04,0008,00012,00016,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliProduction (tons, thousands)b. Crop production, ASP 2008–09IBMRASP 2008–09Figure B.2 Cropped Area and production from IBMR Baseline and ASp 2008–09 in SindhNote: IBMR = Indus Basin Model Revised, ASP = Agricultural Statistics of Pakistan.160 IBMR Updating to IBMR 2008The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6pattern (which means the proportion of each crop in area and production) is very similar to reality.Figures B.3 and B.4 show the cropped area and crop production in NWFP (North-West Frontier Province) and Balochistan,  respectively. The modeling results are underestimated in these two provinces, which can be expected because only the irrigated area was modeled and only small portions of these two provinces are covered by the irrigated network in reality. Ahmad, Brooke, and Kutcher (1990) used a coefficient of determination (R2) to test if the model can 05001,0001,5002,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliCropped area (acres, thousands)a. Cropped areaFigure B.3 Cropped Area and production from IBMR Baseline and ASp 2008–09 in nWFp01,0002,0003,0004,0005,000Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliProduction (tons, thousands)IBMRASP 2008–09b. Crop productionNote: IBMR = Indus Basin Model Revised, ASP = Agricultural Statistics of Pakistan, NWFP = North-West Frontier Province.IBMR Updating to IBMR 2008 161The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6 at least capture the trend of cropped area and production. The R2 for cropped areas are 0.90 and 0.83 for NWFP and Balochistan, respectively. And the R2 for crop production are 0.98 and 0.41 for NWFP and Balochistan, respectively. Balochistan shows the largest differences between modeling results and observa-tion. But since Balochistan only represents a very small portion of the entire Indus River, the results will not significantly affect the basinwide outcome.Table B.1 shows the results of modeling livestock numbers compared to the ASP data. (Only Sindh province has 2008–09 data available, other provinces Figure B.4 Cropped Area and production from IBMR Baseline and ASp 2008–09 in Balochistan05001,0001,500Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliCropped area (acres, thousands)a. Cropped area05001,0001,500Basmati riceIrrigated riceCottonGramMaizeMus+rapSugarcaneWheatOrchardPotatoOnion ChiliProduction (tons, thousands)IBMRASP 2008–09b. Crop productionNote: IBMR = Indus Basin Model Revised, ASP = Agricultural Statistics of Pakistan.162 IBMR Updating to IBMR 2008The Indus Basin of Pakistan • http://dx.doi.org/10.1596/978-0-8213-9874-6have only 2006 data.) Generally, livestock is underestimated. A major reason is that much of the livestock production is in the non-irrigated areas and is not modeled in IBMR. Thus, the modeled livestock numbers are only half of the ASP data. The other possible reason is that in the model bullocks were removed and the ratio between cow and bullock was fixed. This modification might also affect the number of cows and bullocks in the model since the bullock population is capped by the cow population.This appendix provides some diagnosis of the IBMR baseline run compared to observed data. Although the modeling results do not perfectly match the ASP data, they still provide a reasonable framework to assess the irrigated  agro-activities in the Indus River Basin.ReferencesAhmad, M., A. Brooke, and G. P. Kutcher. 1990. Guide to the Indus Basin Model Revised. Washington, DC: World Bank.Government of Pakistan, Ministry of Food, Agriculture, and Livestock. 2010. “Agricultural Statistics of Pakistan 2008–2009.” Islamabad, Pakistan.USDA (U.S. Department of Agriculture). 2009. “Pakistan Sugar Annual 2009 Gain Report.” USDA Foreign Agricultural Service-PK9005, U.S. Department of Agriculture, Washington, DC.Table B.1 Livestock Comparison between IBMR 2008 and ASp 2008–09animals, thousandsCow Bullocks Cattle BuffaloNWFP IBMR 94 47 141 429ASP 2006 5968 1928Punjab IBMR 3074 1537 4611 6178ASP 2006 14412 17747Sindh IBMR 1602 801 2404 4117ASP 2008–09 6925 7340Balochistan IBMR 104 52 156 0ASP 2008 2254 320Note: IBMR = Indus Basin Model Revised, ASP = Agricultural Statistics of Pakistan, NWFP = North-West Frontier Province.

IBMR Updating to IBMR 2008

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IBMR Updating to IBMR 2008

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