Spate Irrigation: Impact of Climate Change with Specific Reference to Pakistan

Spate irrigation is a unique system of agriculture practiced in the piedmont plains by harvesting of floods received after rainfall in the mountains. This system is practiced in different parts of the world; in Pakistan, it is extensive in the western belt. The system is based on water distribution from head to tail. There are laws for distribution of water, but due to the magnitude of flood, it sometimes retains in the upstream and sometimes finds its way to the river. Agriculture practiced in this system depends on floods, which brings sedimentation, useful in replenishing soil fertility. Soil has the ability to hold moisture for long. The changing climatic pattern has greatly influenced the system both under droughts and floods. Livelihood of the spate farmers depends on agricultural crops and livestock. In either case of the extreme climate, they have to cope with limited options. Changing climatic pattern is responsible for extending the climatic seasons and enhancing the irrationality of floods. Construction of huge dam on the torrential watershed is a great project executed by the government for large floods, overcomes energy crisis, and has potential to irrigate land through canal. This chapter is a brief comprehension of spate irrigation under changing climate with special focus on Pakistan.