Canal Flow Requirement Calculator

Work out canal flow requirement instantly with clear inputs, formula shown and shareable results.

About Canal Flow Requirement Calculator

Duty is the area a unit discharge can irrigate — 1800 hectares per cumec is a typical figure for a kharif crop. Net discharge is area divided by duty; the canal head must carry more than that because seepage and evaporation take a share along the way, so the gross figure is net divided by (1 - loss fraction).

Formulas

Discharge from duty

Net discharge (cumec) = command area (ha) / duty (ha per cumec)

Gross at head

Gross = net / (1 - conveyance loss); volume = gross x 86,400 x rotation days

Worked example

With the default values below, Canal Flow Requirement Calculator returns Canal Head Discharge of 0.3472. Change any input above and every figure here is recalculated in your browser.

Inputs used

Command Areaminimum 0.1 ha: 500 ha
Duty Of Waterminimum 100 ha per cumec: 1,800 ha per cumec
Conveyance Lossaccepts 0–80 %: 20 %
Rotation Periodminimum 1 days: 14 days

Results

Canal Head Discharge: 0.3472
Net Discharge At Field: 0.2778
Volume Per Rotation: 0.420
Discharge Lost In Conveyance: 0.0694

Step by step

1Values used
2Discharge from duty
3Gross at head
4Canal Head Discharge= 0.3472
5Net Discharge At Field= 0.2778
6Volume Per Rotation= 0.420
7Discharge Lost In Conveyance= 0.0694

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is a cumec?

One cubic metre per second, equal to 1000 litres per second or about 35.31 cusecs. Volumes are often quoted in million cubic metres (MCM) for a full rotation or season.

How large are conveyance losses?

Unlined earthen canals commonly lose 20-40% of head discharge to seepage and evaporation. Lined canals reduce this to 5-15%, and piped distribution networks lower again.