## Relation Between Base, Delta, and Duty

Let assume,

- ‘D’ is the duty of water, unit hectares/cumec
- ‘B’ is the base period of the crop, the unit in day.
- ‘Î”’ is the total depth of water in unit meters.

We know that one cumec of water is supplied continuously for **B days** to obtain a **depth of water Î”** over an area of land **D hectares**.

Hence, we can write

â‡’ 1 cumec for B days gives Î” over D hectares.

â‡’ 1 cumec for 1 day gives Î” over D/B hectares.

â‡’ 1 cumec for 1 day(**1 cumec-day**) = **(D/B)â¨¯Î”** hectares-meter [Equation 1].

Now, calculate the value of **1 cumec-day** = 1**â¨¯**24**â¨¯**60**â¨¯**60=86400 mÂ³.

We know that 1 hectare is equal to 10000 mÂ², now convert 86400 mÂ³ into a hectares-meter.

So, 1 cumec-day =86400 mÂ³ = **8.64 hectares-meter** [Equation 2]. From equations 1 and 2 we can write

*â‡° (D/B)â¨¯ Î” = 8.64*

*â‡° Î” = [(8.46â¨¯ B)/D*] Unit in meter.

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10 Factors Affecting the Duty of Water