The document discusses the planning and design of irrigation systems for farms. Properly designing an irrigation system requires matching the pumping system's pressure and flow rate to the irrigation distribution system. An irrigation plan is needed to layout the system in the most cost-effective way, provide installation instructions step-by-step, and form the basis for agreements between contractors and farmers. The primary functions of farm irrigation systems are to supply water to crops in the needed quantities and times by diverting, conveying, distributing water within fields and regulating flows.