## Blaney Criddle Method

A simplified formula develops by Blaney and Criddle (1950) in which it correlates the consumptive use of water with the temperature and daytime hours.

By multiplying the mean monthly temperature t by the mean monthly percentage p of the maximum possible daytime hours of the year. A monthly consumptive use factor f is determined by this following equation

f = (pt./100)

The value of p depends on the period of the year and the latitude of the place.

### Blaney-Criddle Formula

The monthly consumptive use is given by this following formula:

**Cu=k.P(1.8t + 32) /40 **

Where

Cu = Monthly consumptive use in cm.

t = Mean monthly temperature in °C.

k = Crop factor, determined by experiments for each crop, under the environmental conditions of the particular area.

p = Monthly per cent of annual daylight hours that occur during the period.

If **P(1.8t + 32) /40 is represented by f, now we get the equation is**

**Cu=k.f**

The consumptive use of water for any given period is given by the sum of the monthly consumptive use values.

Thus, the formula was finally expressed as

**Cu=k∑f**

where C**u** is the seasonal consumptive use of water.

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