Irrigation duration refers to required time for each irrigation. This duration is a function of net water application depth, precipitation rate of sprinkler and irrigation efficiency. Irrigation duration is calculated by the following formula
Ta: Irrigation duration. h.
dn: net water application depth. mm
Pr: Precipitation rate. mm/h
Ea: Application efficiency. % (80% can be taken for sprinkler)
5.2 Lateral flow
Lateral flow changes according to the number of sprinkler which is planned to be placed on the lateral and their flow rate. Lateral flow which they need to carry increases similarly as number of heads and flow rate are increased. The lateral flow inlet is determined by equation 14.
Ql: lateral flow. l/s
qs: sprinkler flow. l/s
ns: the number of sprinkler on lateral
Sprinkler heads having wetting area in shape of circular, semi-circle and quarter circle on the same lateral are often used depending on geometrical shapes of irrigation area. In case of using heads having different flow rate on a lateral, heads which have the same flow rate are grouped and number of heads are multiplied and the total flow rate of lateral is defined.