WATER KNOWLEDGE NOTE Groundwater and Surface Water in the Mega-Irrigation Systems of Pakistan The Case for Conjunctive Management Frank van Steenbergen1 Groundwater use has increased across Pakistan, nowhere more than in the large canal-irrigated areas of the Indus basin irrigation system (IBIS). These mega-irrigation systems use surface water and groundwater, often in equal measure. The two water sources are the same source and should be managed as such. Groundwater supplied by seepage from the surface system is pumped up to complement surface water supplies. The delivery of surface water supplies determines how much groundwater is used and how much recharge will happen. In most cases, such conjunctive management will not “cost” extra water to make significant gains in yields and support drought resilience. This case study discusses Pakistan’s contrasting experiences with conjunctive use in the Punjab and Sindh provinces and attempts to move toward conjunctive management. © Faseeh Shams / International Water Management Institute. The information in this case study was prepared as part of the South Asia Water Initiative (SAWI) technical assistance project, Managing Groundwater for Drought Resilience in South Asia. SAWI is a multidonor trust fund supported by the United Kingdom, Australia, and Norway and administered by the World Bank. Introduction TABLE 1. Distribution of Depth to Groundwater Table Zones in Canal-Irrigated Most of Pakistan’s estimated 1.2 million groundwater wells Areas (June 2000) are within the Indus basin irrigation system, the world’s largest. In this mega-irrigation system, groundwater use has Province offset inadequacies in surface water deliveries, increased the Depth to groundwater Punjab (% Sindh (% amount of water available, and helped end the waterlogging (meters) Irrigated area) irrigated area) that cripples agricultural production and causes unhealthy Less than 1.5 6.2 38.5 living environments. The availability of groundwater also 1.5 to 3.0 18.9 50 ensures that drought periods are dealt with effectively. 3.0 to 4.5 29.3 6.1 In Pakistan’s large-scale irrigation systems, as elsewhere 4.5 to 6.0 14.8 2.9 in South Asia, there is now a “conjunctive reality.” In the More than 6.0 30.8 2.5 irrigation systems, a large part of the water comes from 100 100 groundwater, not from direct surface supplies (Shah 2009). Total area (irrigated) The high density of wells in the surface irrigation systems Million hectares 9.96 5.74 is sustained by seepage water from cultivated land (47 to Source: Salinity Control and Reclamation Projects (SCARP) Monitoring Organization 81 percent, depending on the season) and irrigation canals (16  to 48 percent) (Solangi, Qureshi, and Jatoi 2017). houses, and infrastructure. About 38.5 percent of the Irrigation water in this way is then used and reused in an area  in Sindh has a depth to groundwater table within example of extending the chain of water uses for greater 1.5 meters, classifying it as waterlogged. In the current era efficiency. In conjunctive systems, surface and groundwater of concerns on water scarcity and climate-induced drought, are artificial distinctions used to describe the hydrological such massive waterlogging is almost an aberration. process. In mega-irrigation systems, groundwater and surface water are closely connected and ideally should be comanaged. Groundwater Situational Analysis in Punjab and Sindh This case study discusses how conjunctive management should be implemented in Pakistan’s mega-irrigation Punjab systems. Conjunctive use is widespread, and some conjunctive management is already happening, but there With a population of 90 million people, Punjab is Pakistan’s is much to gain by integrating management of surface and largest province. About 65 percent of the population lives in groundwater in mega-irrigation systems. the rural areas, and agriculture remains an important source of income; therefore, dependable irrigation is essential. This paper discusses two trajectories in Pakistan, largely Average annual rainfall in Punjab is about 390 millimeters, coinciding with the country’s two main provinces in the and evaporation is about 1,500 millimeters. Almost half Indus basin irrigation system – Punjab and Sindh. In of the total land area is irrigated with water diverted from Punjab, conjunctive use has taken off in the last 35 years the Indus and tributary rivers, adding up to 9.96 million with high tube well densities, often more than 20 per 100 hectares of irrigated command area. hectares. Conjunctive use has ended water logging and sustained increased cropping intensities, even to the point Since 2013, Punjab’s political leadership has been of groundwater overuse in parts of the province. In contrast, consistently upbeat about the future of the province and in Sindh a similar transformation has not taken place and ambitions to create a regional agricultural powerhouse. water logging is still a persistent problem. Groundwater use The Punjab Bureau of Investment and Trade2 pointed out accounts for a much smaller portion of water deliveries for the province’s unique selling points: a geographical location two reasons: (a) the existing high and outdated irrigation close to export markets in China and the Gulf states, the water supplies in Sindh, which could be altered, and (b) the world’s largest single irrigation system, and agro-processing salinity underneath a large part of the Sindh canal system, facilities. which cannot be changed. Table 1 shows the contrasting extent of waterlogging, which should be considered in Groundwater is remarkably important in Punjab’s mega- terms of impact on human and animal health, crop yields, irrigation system, both for quantity and reliability. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 2 Agricultural expansion and intensification in Punjab have additional supply of water. In many areas, especially in the been driven largely by the development of at least 900,000 Punjab province, these early SCARP projects lowered water privately operated pumped tubewells in the past 35 years.3 tables and succeeded in bringing land into cultivation again. Most are powered by small-capacity engines, either diesel or electric, driving a centrifugal pump and lifting water The controlled and reduced water tables set the scene for a from shallow depths of less than 10 meters. It is estimated new era of agricultural development. A big boom in private that at least 75 percent of the increase in water supplies in tubewell development started in the 1980s, triggered by the past 25 years is from public and private groundwater the availability of locally manufactured high-speed diesel exploitation. engines. These engines (modeled on the vintage Peter engines) had a capacity of 12 to 16 horsepower and operated Development is also facilitated by a near-perfect aquifer with centrifugal pumps, lifting between 20 and 30 liters underneath this massive irrigation system. Punjab is per second. Investment costs were relatively low (usually underlain by different types of geological formations, but less than US$1,200), which opened the sector to small the main source of groundwater is its alluvial aquifer with farmers. At first, most farmers accessed groundwater by water-bearing formations ranging in thickness of up to renting pump sets, but over time, more farmers developed 500 meters. It is this alluvial plain that underlies the main their own tubewells. The rapid increase in groundwater use irrigation commands. These areas are subdivided into six completely changed the agricultural landscape in Punjab, interfluves or doabs. Good-quality land is generally close leading to increased production and cropping intensity to the river. But in the center of the doabs, far away from and changes in crops, such as a shift from cotton to more the flushing effect of the rivers, groundwater is more saline. vegetables and high-value crops. Groundwater generally occurs under water table conditions Sindh in the alluvial aquifer. Depth to water below the land surface in Punjab ranges from close to the surface near the As table 1 shows, the groundwater situation in Sindh major rivers to more than 20 meters deep away from the province is in stark contrast to the one in Punjab. Although rivers. In 2000, only 6.2 percent of the irrigated land was groundwater is the prime source of irrigation water in waterlogged with water tables within 1.5 meters. the canal commands of Punjab, Sindh has a different conjunctive reality. In no canal command does the water This was not always so. The current conjunctive reality reused as groundwater exceed 30 percent; in most canal in Punjab is a remarkable transformation from the commands, it is far less (Habib 2008). The groundwater situation in the 1960s and 1970s, when the so-called transformation that occurred in Punjab did not happen in twin menace of waterlogging and salinity prevailed. In Sindh to the same degree. these years, groundwater represented only 8 percent of the total usage (van Steenbergen and Oliemans 2002). In As in Punjab, the irrigation system in Sindh is underlain the 1930s, groundwater tables began rising in Pakistan’s by a massive alluvial aquifer but with two important irrigation systems because of excessive seepage from canals, differences. First, a large part of this aquifer system contains overirrigation, and the lack of drainage. It led to a massive groundwater that is too saline for irrigation, especially at crisis in the 1960s, with 52 percent of the land in the entire greater depth. As in Punjab, salinity increases in Sindh country, including Punjab, faced with waterlogging for most with distance from the rivers, resulting from millennia of of the year. At the time, this was considered a global security flushing. But in Sindh, there is only one river and salinity issue and even debated in the United States Congress. is more persistent. The response was what may be called a first attempt at According to Ahmad (1995), many sites have shallow, conjunctive management in Pakistan. Under the Salinity usable groundwater. The total fresh groundwater zone Control and Reclamation Projects (SCARP), starting in at shallow depth (15 meters) is tentatively estimated at 1962, batteries of deep-drainage tubewells were installed 46 percent (van Steenbergen, Basharat, and Lashari 2015), and typically pumped from 40 to 120 meters. They were to but further investigations are needed to precisely assess draw down the groundwater table, reduce waterlogging, and groundwater qualities at shallow depths. In these areas, a bring farmland into cultivation again. In some places, where managed recycling of fresh groundwater and surface water the deep water pumped up was fresh enough, it served as an should be possible. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 3 The second important explanation for the limited use of perennial canals. The problems in the perennial channels in groundwater is the high surface irrigation supplies in several Sindh are different. There, water duties are generally lower, canal commands in Sindh. Van Steenbergen, Basharat, and although still higher than elsewhere in the Indus basin Lashari (2015) reviewed canal water supplies to all canal irrigation system. Salinity is concentrated in areas with command areas in Sindh, highlighting the wide variety of deficient surface water supplies, where there is not enough irrigation allocations across them. The Rice Canal command water for leaching accumulated salts. This often concerns area receives the maximum canal supplies (areal average of the tail reaches of the channels. about 1,700 millimeters), whereas other command areas receive 400 to 800 millimeters. The annual reference crop Although waterlogging is persistent, there has been one evapotranspiration at the nearest meteorological station main exception in recent years. In 1998 to 2002, the in Rohri is 1,931 millimeters. Irrigation duties in Sindh El Niño effect caused rainfall to reduce by more than are high. The overabundance is further amplified by the 50 percent, and releases from the main irrigation reservoirs widespread indiscipline in the shape of diversions into the in the country, Tarbela and Mangla, dropped by 9 percent main canals beyond the official allocations and furthermore and 37 percent, respectively. This resulted in a reduction from the presence of direct outlets, tampered offtakes, or of Pakistan’s surface canal deliveries by 12 to 25 percent canal seepage, reaching high above the ground level. The compared to preceding years (Saeed et al. 2009). This ample availability of free surface water has made pumping drought had a remarkable and unforeseen effect on Sindh’s of groundwater unattractive. irrigated areas. Unexpectedly, crop production did not suffer from the drought and, in fact, increased. Production of These high surface-water deliveries and limited groundwater wheat, rice, cotton, and sugarcane increased by 0.8 percent, use have given rise to widespread waterlogging (table 1). 6 percent, 4 percent, and 6 percent, respectively, during the The twin menace in Sindh is still there. According to more- 1998–2002 drought period compared to the decade before recent data (October 2011), 69.6 percent of the area has the drought. Wheat, rice, cotton, and sugarcane crop yields a root zone that is waterlogged (Basharat, Ali, and Azhar rose by as much as 18 percent, 15 percent, 9 percent, and 2014). The waterlogging conditions in the area remain about 4 percent, respectively. The effect was most pronounced in the same every year, except before the monsoon, because areas with uniform high groundwater tables.4 of the lower canal supplies during rabi season. In acreage, the affected area is colossal at 2.19 million hectares in post- The explanation for this unexpected response to the monsoon 2011. This has a major effect on production drought—less water but more yield—was a significant of rabi crops. For the Sindh province, some 74 percent reduction in waterlogged areas resulting from the reduced of the water available is lost in the form of nonbeneficial inflow and increased use of groundwater to compensate for evaporation (WaterWatch and Osmani 2005). The large the shortfall in irrigation canal supplies. Waterlogging and extent of land that is waterlogged and unproductive further salinity disappeared, particularly in low-lying areas with reduces interest in using groundwater for agriculture. It heavy soils. Figure 1 is a snapshot of this period, showing also undermines the capacity to deal with floods because how the area under waterlogging responded to canal high groundwater tables have limited capacity to store flood supplies. Figure 2 has the same message but zooms in on water in the soil profile. Sindh’s largest canal, the Rohri Canal. Waterlogging is particularly persistent in areas served by The gist of figures 1 and 2 is that: so-called nonperennial canals. These canals are meant to receive copious supplies in the wet kharif season, causing • The waterlogged area increased from 1.27 million the water table to rise significantly and then fall again in hectares in 1991 to 2.26 million hectares meters per the winter season (rabi season), when the canals are not hectare in 1992, responding to high canal diversions flowing. In the Rice Canal in the District Larkana area, of 62 billion cubic meters (BCM) in 1991–92. It for instance, the water table fluctuates between 1 and then dropped to 1.30 million hectares in 1994 as 3 meters during the kharif and rabi seasons. The annual the surface water flows reduced to 44.5 BCM. With cycle of rising and falling water tables brings salts to the increased canal supplies, waterlogging in 1998 again upper soil strata (Mukarram 1984). In some nonperennial touched the 1992 levels. canals, waterlogging problems are compounded because • In 1999–2000, following a drastic reduction in the canals are converted, officially or unofficially, into available supplies, the waterlogged area shrank to WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 4 FIGURE 1. Waterlogging and Canal Supplies in Sindh (1991–2000) 3,000 60 2,500 50 Area in 1,000 ha Canal diversions 2,000 40 1,500 30 1,000 20 500 10 0 0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Waterlogged area Canal diversions Source: van Steenbergen, Basharat, and Lashari 2015. Note: ha = hectare. FIGURE 2. Pre-Monsoon Area under Different Water Table Depths in the Rohri Canal Command 100 80 Area (%) 60 40 20 0 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 0 1 02 03 0 0 19 19 20 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 19 20 19 20 Year 0–150 cm 150–300 cm >300 cm Source: Saeed et al. 2009. Note: cm = centimeters. 285,000 hectares. The same was true for the Rohri Punjab Canal, where groundwater tables within a 3-meter depth almost disappeared up to 2003. As mentioned earlier, a virtual groundwater revolution has occurred in Punjab, where a major portion of Pakistan’s Impact of Groundwater Development— million tubewells are located. These have made up for the The Current Challenges unreliability and shortfall in surface water supplies from the canal system and boosted crop intensity to 172 percent. In As demonstrated above, the impact of groundwater some areas, such as Punjab’s sugarcane wheat zone, crop development has been marked in Punjab and Sindh but has intensities of 234 percent are reached (Mirza and Latif followed a different trajectory in each of these provinces, 2012). This may be compared to crop intensities in the leading to a slightly different presentation of the current pre-groundwater days of 103 percent, 111 percent, and challenges in each province. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 5 122 percent during 1960, 1972, and 1980, respectively over the period. The most pronounced decline (of more (Ahmad 1995). than 3 meters) occurred in Kasur, Khanewal, Multan, and Pakpattan (figure 3). In other areas, the decline was far less The tubewell transformation was a major factor removing (PISIP 2014). The main concern, however, is not so much waterlogging in the freshwater and some of the saline declining groundwater levels but the upconing (upward groundwater zones in the province. It further helped movement in response to pumping) of deeper saline reduce soil salinity—waterlogging’s companion menace. groundwater in areas of intensive pumping (Alam 2015). A comparison of the 2001–03 soil salinity survey for Punjab with an earlier main survey in 1976–79 shows that surface The 2010 floods reversed the trend somewhat. But, overall, salinity declined from 14 to 7 percent after the intense use the pattern is for water tables to rise in districts lying in of shallow groundwater lowered the groundwater table. head reaches of large canals and to decline in districts in tail reaches of irrigation systems with sometimes a deterioration The omnipresent tubewells in Punjab also helped increase in water quality. Another concern is the areas with a drought resilience. The 1998–2002 drought did not result relatively thin layer of freshwater perched on top of saline in a crop loss in Punjab because additional pumping groundwater, where overpumping or inadequately placed compensated for the shortfall in canal supplies. In some skimming wells can jeopardize the resource. areas, crop yields even increased because of the disappearance of waterlogged conditions. A snapshot of what is happening is in the longitudinal study of the Lagar Distributary in Rechna Doab (Ertsen and This intense groundwater pumping in the canal command Kazmi 2015). Researchers examined the area in 1989 and areas in Punjab is largely driven by farmers’ investment. revisited it 20 years later. During that period, the number of Since the mid 2000s, concerns that there may be a limit tubewells increased fourfold, mainly in the head and middle to this success story have risen. Monitoring in 2003–11 reach, because of the generally better groundwater quality in indicates that the overall system is getting slightly out of the head reaches. This occurrence reversed an earlier trend balance, with groundwater levels dropping in 28 of 38 when tubewells compensated for the inadequacy of canal districts. In most cases, the decline is less than 20 centimeters supplies and were overrepresented in the tail. It should be noted that a fourfold increase in tubewell numbers does not mean a similar increase in pumping. As more farmers FIGURE 3. Water Table Decline in Tail Reach obtained a tubewell of their own, utilization rates have Areas in Punjab shown in individual monitoring dropped (van Steenbergen and Oliemans 2002). Another wells trend during those two decades is an increase in electric –40 wells (from 18 to 29 percent) and the virtual disappearance of tractor-driven wells. The most important and worrying –45 development, however, is that there are not only more wells but also deeper wells. In 1989, 7 percent of all wells were Declining GWL trend (feet) –50 deeper than 50 meters, but by 2009, this number rose to –55 30 percent—thus augmenting the risk of increased salinity –60 in irrigation water and thereby that of the soil and shallow –65 groundwater. –70 Despite the intense groundwater use, or overuse, agricultural –75 productivity remains relatively low in the province compared to other parts of the subcontinent. Under the –80 existing field conditions, average wheat production in the p 5 ec 5 a 5 n 6 p 6 ec 6 a 6 n 7 p 7 ec 7 a 7 n 8 p 8 ec 8 a 8 n 9 p 9 ec 9 M 09 Ju r 10 Se 10 10 Ju r 0 Se 0 D 0 M 0 Se 0 D 0 M 0 Ju r 0 Se 0 D 0 M 0 Ju r 0 Se 0 D 0 M 0 Ju r 0 Se 0 D 0 Pakistan Punjab is 1.08 kilograms per cubic meter of water n p n a Ju Date used, compared to the Indian Punjab’s production of 1.42 Monitoring well kilograms per cubic meter of water used (Bastiaansen, Districts KHW–12 Districts LODH–2 Miltenburg, and Zwart 2010). This finding is partly related Districts MTN–68 Districts PKTN–15 to the timing of the cultivation season. To make Pakistan’s Source: PISIP 2014. Note: GWL = Groundwater level; KHW-12 = Khanewal-12; Punjab a food basket of the region, more can be done in LODH-2 = Lodhran-2; MTN-68 = Multan-68; PKTN-15 = Pakpattan-15. water management and advanced irrigation practices. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 6 Sindh Prevailing Groundwater Management Regime Versus Desired Groundwater The situation in Sindh has been less dynamic. A major Outcomes intervention was the development of the Left Bank Outfall Drain, a mega-investment in drainage with a At present, there is no centrally coordinated management budget of nearly US$1 billion to reduce waterlogging. of groundwater in the canal system of Pakistan. It is part of The project targeted 525,000 hectares of land in the a bigger picture in which the canal system is operated as a Sanghar, Nawabshah, and Mirpurkhas districts, some of utility but with little water management. Many initiatives the areas most severely affected by waterlogging. However, by farmers and others have promoted the conjunctive use the project impact was short-lived because of the lack of of surface and groundwater, but there is no central water maintenance and funding. resource management. During the drought of 1998–2002, reliance on private tubewells—some quickly installed— Waterlogging in Sindh remains a massive challenge. managed to overcome drought effects in the mega-irrigation Except during the 1998–2002 drought, waterlogging systems. Even more importantly, the wells helped reduce affects an area of 1.5 to 2.3 million hectaresout of an waterlogging and caused a remarkable rise in production irrigated command of 5.5 million hectares. Soil salinity instead of a decline during the drought. That experience is also a challenge. Salinity increased from 46 percent of was an unrealized opportunity to develop a full-fledged irrigated land in 1979 to 51 percent in 2003. Cropping conjunctive management program. Four steps described intensities are significantly lower than in Punjab with, in the following section could be explored to develop for example, 116.7 percent in Sindh’s cotton and wheat systematic conjunctive management. zone. This low performance comes despite much higher water deliveries and, as discussed previously, is partly Recalibrate Irrigation Duties caused by it. As may be expected, water productivity for wheat in Sindh is low and ranges from 0.32 to 1.15 Irrigation duties in Pakistan’s mega-irrigation system are kilograms per cubic meter (WaterWatch and Osmani outdated. Updating and rationalizing them could be a main 2005). The top score in Sindh is equal to the average instrument to promote conjunctive management of surface value in Punjab. and groundwater. Such work would need to account for current deliveries from the main storage reservoirs, the Waterlogging impacts more than agricultural production. widespread use of groundwater, and even future climate It hurts public health, with higher rates of waterborne scenarios. Surface water deliveries affect the amount of diseases such as malaria, and makes it difficult to dig recharge and determine demand for groundwater supplies. rural pit latrines. It also affects livestock and animal health by increasing diseases such as liver fluke. Housing The challenge in Punjab at this stage is the overuse of and infrastructure are damaged by damp conditions groundwater. Basharat, Ali, and Azhar (2014) investigated (Abdel Dayem et al. 2004). High groundwater tables the scope for the reallocation of irrigation duties in Punjab add up to water management disaster areas such as the and established that only a few canals in Punjab have excess tail-end Badin and Thatta districts. Here groundwater supplies and that irrigation water supplies could be better is saline because of high irrigation supplies (often in spread in some of the larger canals. the rainy season when there is less demand elsewhere), flat topography, and poor natural drainage as a result Updating duties would bring bigger gains in Sindh because of the tidal effect moving upstream after the scouring of high surface irrigation supplies in many of its canal out of the tidal link. The impact extends beyond commands. These high irrigation allocations contribute to agricultural productivity to drinking water supplies. extensive waterlogging and create disincentives for farmers With groundwater levels close to the surface, no fresh or to use groundwater, even in areas where groundwater is brackish water lens can form in the area to provide relief fresh. The drought years of 1998–2002 effectively showed as a drinking water source. The main source of drinking how “less was more” (Saeed et al. 2009). Current irrigation water is the highly polluted water in irrigation canals in duties follow no logic. There is a compelling case to the area. The situation in Badin and Thatta worsened after readjust outdated irrigation duties, accounting for current the 2011 floods—consolidating and further spreading Indus basin irrigation system water availability, the storage the high water tables. capacity of Tarbela and Mangla, and the need to optimally WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 7 manage the groundwater buffer. After the commissioning in different areas. There are several examples of farmers of the Tarbela and Mangla dams, 24 percent more water applying water-saving techniques, achieving high yields, became available from the flow regulation, but canal duties and avoiding waterlogging that is pervasive in the land were not officially recalibrated after the additional water around them. Examples are the systematic use of mulch became available. Irrigation duties should be set to develop (from banana or mango leaves) that reduces evaporation, an optimum balance between surface water supplies and the practice of ridge tilling, the use of micro-irrigation groundwater availability and usage guidelines developed in systems, and the use of low-cost greenhouses. support of this. This approach requires that surface water seepage be equivalent to groundwater use or, in other Selected Investments in Drainage and words, surface water supplies be set at an optimum scarcity Canal Lining to encourage groundwater pumping as a complementary source. Where groundwater is of marginal quality, the A third recommendation is to promote select, well-targeted mixing of supplied surface water and pumped groundwater investments in drainage and in canal lining. The non- should result in usable water quality. functionality of drainage systems (70 to 90 percent) in Pakistan (van Steenbergen, Basharat, and Lashari 2015) The gains may be substantial. Following Sindh’s experience gives a clear message to be judicious in drainage investment. from the drought period of 1998–2002, the rationalization of Drainage is nevertheless essential for conjunctive irrigation duties would make possible huge water savings that management, especially in low-lying areas where care can support the creation of new command areas, preferably should be taken to address persistent waterlogging but not areas with relatively fresh or marginal quality groundwater to “over drain” so that beneficial effects on soil moisture and relatively sandy soils so that highly conjunctive systems from water tables are safeguarded. Investment in drainage, can develop right from the start. Going by the experience in fact, is the measure of last resort, if only because of the of the drought period, it may be possible to develop an large cost implications; where possible, better managing additional area of 500,000 hectares. At present, some of this surface supplies should prevent the problem. expansion is already happening in an uncontrolled manner, with water in drains being fresh from large excess flows and When considering drainage investments, the priority in being pumped by farmers. In reassessing the irrigation duties, many areas should be to improve storm water drainage and the current reuse from drains may need to be considered and restore natural drainage paths that are often blocked by regularized as well. Moreover, more groundwater irrigation road and railway development or urban expansion. Next, by the promotion of shallow irrigation wells will also make selective root zone drainage is required in areas with high it possible to intensify and extend the cropped areas. In areas waterlogged conditions. The main aim is to create enough where freshwater overlays saline water, there is a need to storage space in upper soil layers to ensure adequate soil carefully promote multistrainer skimming wells that exploit aeration for crop growth. Ideally, storage space in saline areas water at a very shallow depth. should allow for the development of freshwater lenses that can be used for local drinking water systems. In addition, Improve Field Water Use Efficiency root zone aeration would help avoid rainfall flooding. In addition to rationalizing irrigation duties, it is There is no reason to develop or maintain public drainage important to look at field water management practices. facilities in fresh groundwater zones because private Some systems have tremendous scope for improved water pumping will normally take care of most of the drainage productivity, such as the rice-wheat system (Aslam 1998). requirement in such areas. Such private pumping will be Precision land leveling and mechanized land preparation further stimulated by the curtailing and rationalizing of can boost agriculture production and water saving up surface supplies, as described earlier. Ideally, where root to 50 percent. Direct seeding and alternative wetting zone drainage is provided, there should be flexibility in and drying, or the introduction of the system of rice water levels because some crops such as rice can tolerate intensification, promises to save water and increase yields high water tables, whereas other crops benefit from sub- at the same time. irrigation. Finally, canal lining should be focused on areas where seepage from the canals system cannot be easily In addition, there is a large range of smart water techniques retrieved as groundwater recharge, primarily in areas with now available. Some of these methods are in use by farmers high salinity. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 8 Make Better Use of Salinity upstream in Punjab, depriving Sindhi farmers. The reality is different, with high irrigation duties in Sindh further A fourth recommendation is to make better use of augmented with unauthorized diversion. This current salinity. There are several options to achieve high yields political narrative in Sindh precludes a systematic look by using relatively saline groundwater, and this needs to at the province’s water resources and opportunities for be better developed. One direction is the use of bio-saline distributing and spreading it better. There is hope, however. systems, such as special farming and fisheries rooted in In 2018, the National Water Policy (Government of Pakistan saline conditions but with good returns in areas that are 2018) was adopted with one chapter dedicated exclusively otherwise considered wasted. A second powerful option to groundwater. The policy has several elements that are is cultivation of common crops under saline conditions, closely intertwined with making conjunctive management using selected varieties and adjusted management a reality, such as preparing groundwater budgets for canal practices. Research by Salt Farm Texel indicates that command areas and promoting higher water productivity. several existing varieties of common crops—wheat, The systematic promotion of conjunctive management of sorghum, sugar beet, and potatoes—adapt surprisingly surface and groundwater fits with all these cornerstones of well to brackish water, particularly in free-draining soils. the National Water Policy. Salt-tolerant potato varieties were introduced over three seasons in 2015 to 2017 on 13 hectares in saline areas in Conclusions Punjab and Sindh. Farmers planted the varieties in areas with salinity levels in the range of 8 to 10 deciSiemens The provinces of Punjab and Sindh are each endowed per meter (approximately 6500 ppm – 8000 ppm total with a massive alluvial aquifer underneath their mega- dissolved solids), areas usually considered out of bounds irrigation systems, which makes it possible to collect for potato cultivation. Yields of the best-performing seepage from irrigated fields and canals and reuse it. The varieties were 23 tons per hectare on average, with some practice has been in use for several decades, but conjunctive varieties producing 40 tons per hectare. Considering management could be strengthened to realize benefits such that the national average on non-saline soil is 20 tons as an expanded command area, reduced waterlogging that per hectare, this finding shows that salt-affected soils would reduce health problems and damage to housing, and can be very productive and even outcompete crops on improved capacity to absorb floods or unusual rainfall in non-saline soils when the right potato variety is used in the topsoil and shallow aquifers. combination with a cultivation strategy for saline soils. In Sindh, the potatoes grown in salt-affected soil could enter Putting in place a proper conjunctive management regime the market early at premium prices. in Sindh will require some steps, including documenting and recording present water use and water productivity All these measures come at high benefits and low cost, but (with help of remote sensing), preparing water balances they require an organizational regime to put them in place. per canal sub-command and discussion, communicating Currently, the attention paid to groundwater policy in with all stakeholders including farmer organizations, and Pakistan is lacking in commitment. There are also some hard removing political resistance. This can all be planned and constraints in the prevailing water management regime. The budgeted. The substantial benefits of doing so would far first is that there is no capacity in the irrigation administration exceed the investment. to go beyond supervising the irrigation utility. There is no manpower, skills, or interest to manage water resources NOTES within the mega-irrigation system. In Sindh, for instance, a graduate engineer will typically manage 300,000 hectares of 1. MetaMeta Research, s-Hertogenbosch, The Netherlands. irrigated land with the support of two or three sub-assistant 2. Punjab Agricultural Sector Profile. engineers. Compared to other mega-irrigation systems, this 3. Based on tubewell densities in the selected area, the is very thin coverage. There is simply not enough staffing author of the case study is of the opinion that the number to do more than keep the infrastructure running. A second is much higher—probably close to 2.5 million shallow constraint is the politicization of Pakistan’s water resources tubewells. management. The main issue is the upstream-downstream 4. The increase in production was not uniform in areas with rivalry between the country’s two main provinces, in which limited surface supplies (higher land and tail reaches). Sindh politicians contend that irrigation water is diverted Crops with no access to fresh groundwater declined. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 9 REFERENCES Mirza, G. M., and M. Latif. 2012. “Assessment of Current Agro-Economic Conditions in Indus Basin of Pakistan.” In Abdel-Dayam, S., J Howevenaars, P.P. Mollinga, proceedings of International Conference on Water, Energy, W.  Scheumann, R. Slootweg, F van Steenbergen. Environment and Food Nexus: Solutions and Adaptations 2004. Reclaiming Drainage: Towards an Integrated Under Changing Climate. Lahore, Pakistan. 4-5 April 2012. Approach. The International Bank for Reconstruction and Development Agriculture & Rural Development Mukarram, A. 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Wageningen, The Netherlands: _evolution_of_Indus_Basin (accessed 22 March 2015). WaterWatch. WATER GLOBAL PRACTICE CASE STUDY | GROUNDWATER AND SURFACE WATER IN THE MEGA-IRRIGATION SYSTEMS OF PAKISTAN 10 Connect with the Water Global Practice www.worldbank.org/water ­ worldbankwater@worldbank.org ­ @worldbankwater ­ blogs.worldbank.org/water © 2019 International Bank for Reconstruction and Development / The World Bank. Some rights reserved. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent. The World Bank does not guarantee the accuracy of the data included in this work. This work is subject to a CC BY 3.0 IGO license (https://creativecommons.org/licenses/by/3.0/igo). The World Bank does not necessarily own each component of the content. 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