63 Operational Research Tools in Irrigation - A Review Zia ul Haq1, Muhammad Nasir Jamal2, Naseeb Gul3, Jehan Zeb Khan4, Ayaz ur Rehman5 Corresponding Author, Muhammad Nasir Jamal, mnjuet85@gmail.com, Abstract: Operational research optimization is an old method for allocating scarce resources with maximum benefits and efficiency. With increasing global water scarcity, earliness and tiredness in demand base water supply, economical issues, maximizing crop per drop of water, OR is getting popular in irrigation and agriculture sector as well. This paper is intended to review different optimization techniques used so far in the field of irrigation. Key Words: Operation research, optimization, irrigation, water delivery, genetic algorithm, simulated annealing, fuzzy sets, swarm optimization. Introduction : Heger, 2006, define operation research (OR) as the discipline that helps us in decision making and which is based upon the information technology. In other words it is the study of allocation of scarce resources. Galati, unknown, OR is study of mathematical models for complex organizational systems. He further elaborate that OR started in Britain just before World War II, when team of scientists was assigned a task to research on the tactical and strategic military operation problems. Main objective was to utilize limited resource for more benefits. After that in peace time, same techniques was applied in different other fields as well. Optimization Research : As per Galati, unknown, optimization research is the branch of OR which uses mathematical techniques such as linear, nonlinear programming to drive value for the system variables that will optimize the performance. Role of OR : Both in private and public sector OR play an increasingly imported role. It can be very helpful in vast range of problem solving fields, like, revenue management, finance, IT operations, communications, production, transportation, inventory management, and much more. OR works on very simple approaches, i.e. decomposition of problem in basic components and then solving with the help of mathematical tools. Heger, 2006, mentioned that OR has many advantages like