Climate change and variability will impact water availability and the food security of India. Trend analyses of historical data indicate an increase in temperature and changes in rainfall pattern in different parts of the country. The general circulation models (GCMs) also project increased warming and changes in precipitation patterns over India. This chapter presents examples of model applications in water management and crop yield simulation in India, focusing on climate change impact assessment. Simulation models have been successfully applied for rotational water allocation, deficit irrigation scheduling, etc. in different canal commands. Application of a universal soil loss equation in a distributed parametric modeling approach by partitioning watershed into erosion response units suggests that by treating only 14% of the watershed area, a 47% reduction in soil loss can be achieved. Simulation studies conducted using different hydrological models with different climate change projections and downscaling approaches showed varied hydrological responses of different river basins to the future climate change scenarios, depending on the hydrological model, climate change scenarios, and downscaling approaches used. Crop yield modeling showed decreases in irrigated and rainfed rice (Oryza sativa L.) yields under the future climate change scenarios, but the decrease is marginal for rainfed rice. Maize (Zea mays L.) yields in monsoon may be adversely affected by a rise in atmospheric temperature, but increased rain can partly offset those losses. Wheat (Triticum aestivum L.) yields are likely to be reduced by 6 to 23% and 15 to 25% during the 2050s and 2080s, respectively. A combined bottom-up participatory process and top-down integrated modeling tool could provide valuable information for locally relevant climate change adaptation planning.

We explore processes that enable effective policies and practices for managing the links between water, energy, and food. Three case studies are assessed at different scales in the Mekong River basin, Sri Lanka and Zimbabwe. We find that there are considerable opportunities for improving outcomes for sustainable development by finding solutions that accommodate multiple objectives in the nexus. These include making data more publicly available, commissioning independent experts to advise on contested issues, engaging under-represented stakeholders in decision-making, sharing benefits, exploring different perspectives in forums where alternative development options can be tested and engaging decision-makers at different scales.

We explore processes that enable effective policies and practices for managing the links between water, energy, and food. Three case studies are assessed at different scales in the Mekong River basin, Sri Lanka and Zimbabwe. We find that there are considerable opportunities for improving outcomes for sustainable development by finding solutions that accommodate multiple objectives in the nexus. These include making data more publicly available, commissioning independent experts to advise on contested issues, engaging under-represented stakeholders in decision-making, sharing benefits, exploring different perspectives in forums where alternative development options can be tested and engaging decision-makers at different scales.

Asia accounts for 70% of the world's irrigated area and is home to some of the oldest and largest irrigation schemes. While these irrigation schemes played an important role in ensuring food security for billions of people in the past, their current state of affairs leaves much to be desired. This paper takes forward the IWMI-FAO-ADB (Asian Development Bank) recommendation of a five pronged approach for revitalizing Asia's irrigation and provides a region specific road map for doing this. The underlying principle of these multiple strategies is the belief that the public institutions at the heart of irrigation management in Asia need to give up comfortable rigidity and engage with individual users' needs and the demands placed by larger societal chang.

Asia accounts for 70% of the world's irrigated area and is home to some of the oldest and largest irrigation schemes. While these irrigation schemes played an important role in ensuring food security for billions of people in the past, their current state of affairs leaves much to be desired. This paper takes forward the IWMI–FAO–ADB (Asian Development Bank) recommendation of a five-pronged approach for revitalizing Asia's irrigation and provides a region-specific road map for doing this. The underlying principle of these multiple strategies is the belief that the public institutions at the heart of irrigation management in Asia need to give up comfortable rigidity and engage with individual users' needs and the demands placed by larger societal changes.