灌溉排水系统工程

Water is an essential resource for overall development of human settlements. While the demand for water is rising with increase in population and improvement in standard of living, supply of natural water remains more or less constant. As a consequence, the cost of procuring water is increasing fast. Industries and major urban settlements in India and other countries with water shortage have already started taking appropriate measures for conservation of water and optimization of water usage. Currently, the agriculture and irrigation sector has to compete for water with other sectors, an overall irrigation strategy needs to be formulated for ensuring equitable and economic distribution of water in the basin set up.

Various types and formats of irrigation usage have been significantly contributed to development of human civilisation over centuries starting from irrigation by flooding in the Indus Valley civilization to irrigation by canal system in the mauryan period and commercialization of irrigation water in the twentieth century.

This paper presents the state-of-the-art concepts of various issues connected with modernization of canal and water usage system. It is observed that modernization of irrigation needs improvement in all aspects of water usage in agriculture and irrigation. Two most important aspects in this context are Water Productivity and Irrigation Scheduling. Water productivity facilities production of the same quantity of crop by using less water along with more efficient management. In India, excess water accumulates on the field during periods of heavy rain. Such excess water can be utilised either by proper drainage and reutilization of drained water in the same command or in some other command or by allowing the water to recharge the aquifer below the irrigated field and developing a proper system of conjunctive use of surface and ground water.

Accurate irrigation scheduling is a complex issue, depending on both climatic and crop factors. In India, water availability varies widely over space and time. Hence, a long term irrigation scheduling study can be carried out only through stochastic simulation of long term hydrologic water balance data. However, for immediate field decisions, advanced instrumentation system has to be adopted.