Conjunctive water management for sustainable irrigated agriculture in South Asia

• Pakistan Council for Research on Water Resources, Pakistan
• CSIRO Land and Water, Australia

Conjunctive water management refers to the management of waters from all sources within a water basin. Its correct application leads to an increase in the amount of available water. Water considerations are major components of any program of socioeconomic development and poverty alleviation for many developing countries. Governments and development agencies recognise this and invested heavily in water resources development projects during the 20th Century.
Currently, opportunities for further water resources development are limited, either due to the absence of water or lack of financial resources. In the meantime, due to a steady rise in population, demand for food continues to increase. Irrigated agriculture, which consumes 69 per cent of all freshwater resources and produces 40 per cent of all food, is expected to require an additional 17 per cent of water to meet the demand for food. This water is not available from primary sources (rain, snow melt or groundwater). Further, freshwater consumption in irrigated agriculture must be reduced to meet the increasing demand for fresh water for domestic and industrial requirements. Therefore, water from all primary sources as well as from secondary sources (drainage, sewage) needs to be used conjunctively in agriculture.
South Asia had no capacity to carry out effective conjunctive management. Proper institutional and technical strategies were needed to manage water conjunctively and minimise threats to the environment. This study aimed to address these concerns. The Rechna Doab region of Pakistan and the Coleambally region in New South Wales, Australia were chosen as the study sites because, while both have access to surface and groundwater supplies, overall water is the limiting factor for agricultural production. Institutional reforms in the water sector were under way in both countries, and both study areas fell in semi-arid environments with little natural drainage due to flat topography. Thus, the environmental consequences of irrigated agriculture (salinity and waterlogging) were similar in the two regions.

This project aimed to identify and test combinations of technologies, institutions and management tools to conjunctively manage surface and subsurface water. The main objectives were to maximise the short-, medium-and long-term agricultural productivity of water, facilitate water savings and ensure environmental sustainability of irrigated areas in South Asia and Australia.

The study was carried out by IWMI in collaboration with Pakistan Council of Research Water Resources (PCRWR), and CSIRO Land and Water, Griffith, NSW, Australia. Researchers identified combinations of institutional and technical strategies that promoted sustainable conjunctive water management at the regional scale. They evaluated the technical feasibility of providing irrigation water of acceptable quality from multiple sources in a timely manner across an irrigated region and their environmental and economic/financial consequences. They transferred newly designed technology and knowledge to stakeholders at the study sites in Pakistan and Australia.

Key outcomes included identification of institutional constraints for sustainable conjunctive water management in the Rechna Doab. A Nodal Network Model was developed for Rechna Doab. Technical constraints to conjunctive water management were also identified, using Rechna Doab surface and groundwater interaction model and a customised SWAGMAN Farm model.
Scientists developed a solute transport model for Coleambally Irrigation Cooperative Limited (CICL) and undertook a feasibility analysis of the surface evaporation basin. They identified shallow and deep groundwater pumping options in the Coleambally Irrigation Area.
As a result of the study the Punjab Irrigation Department (PID) has adopted institutional arrangements identified by the project team. As well the CICL has adopted shallow and deep groundwater options, and reorganised the environmental zones in terms of groundwater management zones defined by the project team.
In order to disseminate the results of the project to various stakeholders, researchers and policy makers the project team held a two-day workshop in April 2002 in Lahore. Stakeholders heard presentations and were later involved in extensive discussions. On the first day the papers addressed modelling conjunctive water management and technical issues regarding conjunctive water management, drawing on the experience in Pakistan and Australia.
The four papers on the second day of the workshop covered the economic and institutional aspects of conjunctive water management. There followed panel discussions to formulate strategies and recommendations for sustainable conjunctive water use. During the third session of the workshop participants received hands-on training and demonstrations of technical and management tools.