NOTES AGRICULTURAL & RURAL DEVELOPMENT CONJUNCTIVE USE OF GROUNDWATER AND SURFACE WATER BY: THE WATER FOR FOOD TEAM ISSUE 6 FEBRUARY Conjunctive water use refers to simultaneous use of sur- 2006 Box 1: Benefits of Conjunctive face water and groundwater to meet crop demand. Each day, hundreds of thousands of farmers in canal, Management in Madhya Ganga tank, and other surface irrigation systems combine sur- Canal Project, Uttar Pradesh, India face water with groundwater. They do so in an individ- River diversion systems often use lined canals ual manner, uncontrolled by any scheme or basin-level to remove excess floodwaters during entity. Conjunctive management, by contrast, refers to monsoon. However, simple modifications in efforts planned at the scheme and basin levels to opti- infrastructure and the operating system can mize productivity, equity, and environmental sustainabil- transform this waste into wealth. Uttar ity by simultaneously managing surface and groundwa- Pradesh had a network of disused earthen sur- ter resources. In many systems and basins, such planning face drains constructed in the 1950s to control is needed to raise crop water productivity. waterlogging and floods. After the 1950s, intensification of groundwater use created Conjunctive management occurs when system admin- new opportunities for conjunctive manage- istrators control ground and surface water simultane- ment by building check structures at suitable ously. It may be achieved by modifying the configura- intervals to promote groundwater recharge tion of the surface system and its operating procedures with monsoon floodwaters. In the course of a (Box 1). It is less widespread than conjunctive use 10-year collaborative study, scientists from the because it requires institutions and coordinating mech- International Water Management Institute anisms that few client countries yet have. Conjunctive (IWMI), Roorkee University, the Water and management is complex and can be controversial. Land Management Institute, and the Uttar Nevertheless, it can be paramount, particularly in water- Pradesh Irrigation Department found that scarce regions and in times of drought, because failure using these modified drains for monsoon flood to integrate conjunctive water resources can result in irrigation produced the following benefits: groundwater overexploitation. · A 26 percent increase in net farmer income · A decrease in average depth of ground- water from 12 meters in 1988 to 6.5 meters in 1998 · Annual energy savings of 75.6 million kilowatt hours and pumping cost savings of Rs. 180 million · An increase in canal irrigation from 1,251 hectares in 1988 to 37,108 hectares in 1998 · A 15-fold increase in rice area · A 50 percent reduction in conveyance losses in canals Source: IWMI 2002. Users of surface irrigation systems install tubewells as part of a strategy to avoid yield loss caused by unreliable water delivery. Tubewell irrigation water is costlier but offers control and helps save input investments. Farmer FAO/17187/G.Bizzarri tubewells raise the productivity of irrigation systems, extend Growing wastewater use in periurban agriculture in cities the area served, and help prevent waterlogging. In some sit- around the world are a case in point. Research by IWMI in uations, they reduce public investment in drainage by pro- several cities in India, Pakistan, and Mexico points to ingen- viding vertical drainage. High-income countries have finely ious practices developed by periurban farmers to use urban developed conjunctive management to even out spatial and wastewater and groundwater conjunctively for irrigation temporal variations in regional water availability (Blomquist, (Buechler and Devi 2003). However, in water-scarce situa- Heikkila, and Schlager 2001). tions, some industrial wastewater also offers opportunities for livelihood creation through irrigation (Box 2). Since surface irrigation practices directly influence ground- water recharge, improved main system management is key to conjunctive management of surface and groundwater Box 2: Conjunctive Use with Poor- resources. These improvements may require changes in the Quality Water: Irrigation with Mine infrastructure but are more a question of building technical Water in South Africa capacity, adapting the organizational and institutional frame- work for more efficiency, and improving information and communication systems. Disposal of mine wastewater is a problem wher- ever there are coal and gold mines, as in South Potential Areas of Investment Africa. High concentrations of salt make the wastewater unsuitable for direct discharge into rivers except in periods of high rainfall. The poten- Five areas of investment opportunities appropriate for differ- tial for irrigating with mine water in suitable soils ent conditions follow bellow: is increasingly viewed favorably as a way of solv- ing the twin problems of wastewater disposal and RECONFIGURING SURFACE IRRIGATION PROJECTS. shortage of irrigation water. How big the oppor- Many surface irrigation projects were designed under a slew tunity is depends on the availability of suitable of antiquated assumptions about cropping patterns and soils nearby, the resultant soil water and salt bal- hydraulic infrastructure in the command. Reconfiguring the ance for different cropping systems, the choice of main system, rationalizing the operating rules and practices, irrigation management strategies, and the impact and training system managers to operate the modernized of the irrigation drainage on local and regional system in a conjunctive management mode offer a major water resources. The approach is inherently con- investment opportunity. junctive, because polluted mine water is used to complement inputs from rainfall and stream flows. GROUNDWATER RECHARGE TO SUPPORT INTENSIVE GROUNDWATER IRRIGATION. A new development in dense- In a field trial in South Africa during 1997-2000, ly populated areas of Asia is intensification of well irrigation in three center pivots were set up for irrigation with regions where rainfall precipitation is the only source of ground- coal mine wastewater--one in virgin soil water recharge. Western and southern India have experienced (unmined) and two in mine-rehabilitated land. this phenomenon on a significant scale. In those two regions Several crops were successfully irrigated with gyp- the number of groundwater wells has increased from fewer siferous mine water on a commercial scale. than 100,000 in 1960 to nearly 12 million today (Shah, Singh, Excellent yields were obtained for wheat on both and Mukherjee 2004). With falling aquifers and erratic rainfall, virgin and rehabilitated land, and also short-sea- local communities and governments are turning to constructing son maize grown on virgin land. The yields of local water harvesting and recharge structures on a massive sugar beans were reasonable and higher than scale with the primary objective of increasing groundwater with dry land cropping. Problems that caused yield availability for improved drinking-water security, drought proof- reductions were not related to irrigation with gyp- ing, and protecting rural livelihoods. Evidence suggests that siferous mine water and were recognized as sur- these community-based investments significantly stabilize liveli- mountable with experience in the management of hoods in regions that may never benefit from large surface irri- the system. Research is continuing, using catch- gation projects (Shah 2003), especially if accompanied by ment-scale computer modeling to assess the investments in demand-side irrigation management through impact of scaling-up on the volume and quality of real water resources savings (Foster et al. 2002). surface water and groundwater. CONJUNCTIVE USE WITH POOR-QUALITY WATER. Source: Olufemi Idowu and Simon Lorentz, University Difficulties and costs involved in disposing of wastewater of Kwa Zulu Natal, with inputs from IWMI, Africa. often present new opportunities for conjunctive use. 2 CONJUNCTIVE MANAGEMENT OPPORTUNITIES IN Policy and Institutional Issues TOWNS. Rapid urbanization in many parts of the world have CONJUNCTIVE MANAGEMENT REQUIRES A BASIN created new threats for periurban agriculture. However, con- PERSPECTIVE. Where practiced, conjunctive management is junctive management of rainfall, surface water, and ground- often confined to the irrigation-system level. Overall gains water creates new opportunities to meet these threats. from conjunctive use can be enhanced by managing resources at the riverbasin level, but this cannot be done until CONJUNCTIVE USE WITH SALINE GROUNDWATER. the river basin becomes part of the water and land manage- In regions with primary salinity, conjunctive use of surface ment unit. and groundwater presents unique challenges and opportuni- ties. In such places the objective of conjunctive management REFORM OF WATER RESOURCES MANAGEMENT is to maintain both water and salt balances. In this situation, INSTITUTIONS. A major obstacle to conjunctive manage- system managers require great control and precision in canal ment is the fragmented structure of governmental institu- water deliveries to different parts of the command to main- tions entrusted with various water management roles. tain an optimal ratio of fresh and saline water for irrigation Typically, the main system is managed by irrigation depart- (Murray Rust and Vander Velde 1992). In many systems, it ments, groundwater by groundwater departments, and makes sense to divide the command areas into surface water energy supply for groundwater pumping by an electricity util- irrigation zones and groundwater irrigation zones, depend- ity. Seldom is there any coordination among these line ing on the aquifer characteristics and water quality parame- departments. These roles must be coordinated if conjunctive ters. In others, providing recharge structures within a surface water management is to succeed. system is often a useful component of a rehabilitation and modernization package. It is a risky business and requires a MONITORING AND INFORMATION SYSTEMS. Improving sound conceptual model of the fate of the salts mobilized, if monitoring of groundwater behavior and use patterns in the it is not to cause more problems than it solves. conjunctive management domain is a priority. Most develop- Potential Benefits of Reform ing countries have poor monitoring infrastructure. This pre- cludes spatially coordinated use of groundwater and surface water that is critical in a saline environment. Geographic Conjunctive water management strategies help reduce evap- databases with data on cropping patterns, evapotranspira- oration losses from reservoirs, for their storage can be drawn tion, groundwater levels, and canal alignments would be a down more quickly if groundwater can be relied on to meet valuable aid to understanding where canals contribute most water needs later in the year. Conjunctive management can seepage to groundwater, where water-intensive perennial also add to drought proofing. Surface water storage varies crops are grown, where soil salinity is inherent or due to far more than groundwater storage in response to interyear waterlogging, where soil salinity could be controlled by leach- variations in precipitation. As a result, groundwater can play ing with irrigation water, and where waterlogging is caused a powerful drought-mitigating role when surface and by improper surface drainage. groundwater are managed and used conjunctively. In the sit- uations identified above, the key benefits of investing in con- PUBLIC-PRIVATE PARTNERSHIP. In many surface irrigation junctive use are the following: systems, public tubewells are used to stop waterlogging and secondary salinization due to surface irrigation. Experiments · Enhanced yield of past investments in surface water irriga- with the Salinity Control and Reclamation project tubewells tion projects through increased irrigated area, improved in Pakistan and the Satjej-Yamuna Canal in northwest India water productivity, and expanded production, employ- have shown, however, that private tubewells often do the ment, and incomes same job as well or better. The problem is lack of coordina- · Improved sustainability of groundwater irrigation in tion in private tubewell development. Since surface systems regions of intensive groundwater use with inadequate are managed by government departments and tubewells are availability of runoff for recharge operated by independent farmers, opportunities arise for · Use of poor-quality water to increase agricultural produc- mutually gainful public-private partnerships with better coor- tion, employment, and incomes dination and an appropriate policy framework. · Enhanced long-term environmental sustainability of irrigat- ed agriculture in salinity dominated environments by REHABILITATION AND HARDWARE IMPROVEMENT. improving salt balances and sustaining the productivity of Reshaping the hydraulic infrastructure is critical where ground- irrigated agriculture water levels are shallow, soils are saline but still favorable, soils are coarse rather than fine, and canal seepage is abundant. 3 Remote sensing can be used to identify such areas. Hardware conjunctive management capacities--through improved improvement should improve control of water levels in main monitoring systems, institutional reform, improved man- and branch canals; automate flow measurement and control agement practices, and greater incentive compatibility. in distributaries, minors, and water courses; and upgrade the distribution network and field channels. Conclusion Lessons Learned To optimize conjunctive use of water, the best way forward is to concentrate on capacity building of irrigation system man- · Conjunctive use of groundwater and surface water often agers to improve system management and reshape hydraulic occurs by default. Big opportunities to enhance its gains lie infrastructure of large and small-surface systems. To sustain in introducing planned conjunctive management through groundwater use in tubewell-irrigated areas, enhancing coordinated strategies at various levels from the river basin recharge from precipitation and surface water imports is nec- down. essary. None of these improvements can be made without · To achieve effective conjunctive management, planned the proper institutional and organizational development, investments are required in hardware (system moderniza- including investment in the capacities of local governments tion and improved infrastructure), software (improved to lead on participatory groundwater management and inte- database), planning and management capacities, and insti- grated water resources management. tutional reform. · Improving main system management is central to better con- junctive management and water level control is critical for REFERENCES better main system management. New technologies offer Blomquist, W., T. Heikkila, and E. Schlager. 2001. "Institutions and big opportunities. For instance, expensive communication Conjunctive Water Management among Three Western States." infrastructure can be replaced by low-cost cell phones. Natural Resources Journal 41(3): 653-84. · Conjunctive management in a poor water quality environ- Buechler, S., and G. M. Devi. 2003. "The Impact of Water ment presents more difficult, and often unique, technical Conservation and Reuse on the Household Economy" Proceedings and management challenges requiring higher investment. of the Eighth International Conference on Water Conservation and Reuse of Wastewater, Mumbai, September 13-14. A key challenge is to create strong incentives for conjunctive Foster, Stephen, Albert Tuinhof, Karin Kemper, Hector Garduno, management among different stakeholder groups. Typically, and Marcella Nanni. 2002. "Groundwater Management Strategies." perverse incentives through faulty pricing of surface irrigation, GWMATE Briefing Note 3. Sustainable Groundwater Management: electricity for pumping, and investment in groundwater struc- Concepts and Tools series. Online at http://www.worldbank.org/ tures undermine gains from conjunctive water management. gwmate. Recommendations IWMI (International Water Management Institute). 2002. "Innovations in Groundwater Recharge." IWMI-Tata Water Policy Briefing, No. 1. Available online at http://www.iwmi.cgiar.org/ · Even where river basin institutions are absent or underde- waterpolicybriefing/files/wpb01.pdf. veloped, planning of conjunctive management seems best done within a river basin framework. Murray Rust, H., and E. Vander Velde. 1992. "Conjunctive Use of Canal and Groundwater in Punjab, Pakistan: Management and · The biggest new opportunities for improving food security Policy Options." Advancements in IIMI's Research 1992. A Selection and livelihoods arise in densely populated agricultural of papers presentedat the Internal Program Review. Colombo, Sri regions that rely on intensive use of groundwater in agricul- Lanka: International Irrigation Management Institute. ture. In such cases, conjunctive management requires a par- Shah, T. 2003. "Decentralized Water Harvesting and Groundwater adigm shift. The need and pressures are for augmenting and Recharge: Can These Save Saurashtra and Kutch from Desiccation?" concentrating groundwater recharge--through recharge IWMI-Tata Water Policy Program, Colombo, Sri Lanka. structures to increase percolation from rainfall and runoff, as well as from imported water-in pockets of groundwater- Shah, T, O. P Singh, and A. Mukherjee. 2004. "Groundwater Irrigation and South Asian Agriculture: Empirical Analyses from a intensive use. Large-Scale Survey of India, Pakistan, Nepal Terai, and Bangladesh." · Conjunctive management investments should strike a Paper presented at IWMITata Annual Partners' Meeting, Anand, India, balance between improving infrastructure and building February 17-19. This Note was prepared by Tushar Shah, Principal Researcher at the International Water Management Institute and updated by Salah Darghouth and Ariel Dinar from the Water For Food Team of the World Bank. It is based on Investment Note 4.3 in the larger volume Shaping the Future of Water for Agriculture: A Sourcebook for Investment in Agricultural Water Management. The Sourcebook documents a range of solutions and good practices from WorldBankandworldwideexperience,concentratingoninvestmentsinpolicyandinstitutionalreformsintechnologyandmanagementtoimprovewater productivity and farming profitability. You can download a copy of the full report at www.worldbank.org/rural or email ard@worldbank.org. THE WORLD BANK 1818 H Street. NW Washington, DC 20433 www.worldbank.org/rural