Facility Piping Systems Handbook, Second Edition

This chapter will provide the information necessary to design an economical irrigation system for delivering the water required to keep plants healthy and to ensure that this water will be applied evenly to all cultivated areas of the site. Generally accepted means of estimating the amount of water needed, selection of equipment (heads and piping), head-spacing criteria (to produce an even distribution of water), and design criteria for sizing the piping system, choosing timers, and sectioning will be described.
The Department of Agriculture has estimated that grass is the largest irrigated crop in the country. Much of the time, the water used for irrigating this crop is the most expensive water available. Watering on a regular basis is necessary for the continued beauty and health of the grass in these areas, not to mention protecting the investment that the owner has made in the cultivated areas.
In order to find the amount of water that is considered adequate for irrigation purposes, the expected rainfall, soil type, plant type, and irrigation requirements for the site must be known. The total overall quantity of water required to keep plants healthy is based on the difference between the natural rainfall and the minimum amount of water necessary for a healthy lawn. The design must consider the worst condition, which is during times of drought when no rain has fallen. This is the basic criterion used to determine the irrigation rate.
The design of cultivated lawn and turf areas requires the planning and...