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However, when water is flowing or in dynamic condition, the dimension of time
has to be brought in. 1 cu.ft. of water flowing in one second is 1 cu.ft./sec. or 1
CuSec or one Cubic Metre of water flowing in one second, it is one cubic metre/
sec or one cumec. In irrigation practices, if there is a standing column of water
of 1 ft in one acre of area, it is known as 1 acre.ft. of water. Similarly, 1 m of
standing water in one ha. Of area, it is 1 ha.m. of water. Water is also measured
in gallons. British or Imperial units of gallons is slightly higher than US gallons
i.e. 1 US gallon = 0.8 Imp. Gallon (approximately).
Flowing river/stream water is measured either in cusecs or cumecs. Flowing
water from the delivery pipe of a tubewells (tubewell discharge) is also
measured in cusecs or cumecs or in litres (1000 CC). Standing water in a
reservoir or pond is measured in cu.ft. or cubic metres of kilo litres.
Conversion :
1 cubic foot = 7.4805 gals (US)
= 0.02832 m
3
= 28.32 litres
1 Acre foot
= 43,560 ft
3
= 1233.49 m
3
= 325,851 gals (US)
1 gallon (US) = 0.134 ft
3
= 0.003785 m3
= 3.785 litres
1 cubic meter= 8.11 x 10
-4
Ac ft.
= 35.3147 ft3
= 264.172 gal (US)
= 1000 litres
= 10
6
cm
3
Flow rate
1 cubic foot per second = 0.028316 m
3
/ s.
= 447.8 gals (US)/min (gpm)
1 gallon (US) per minute = 6.31 x 10
-5
m
3
/sec.
1 million gals (US) per day = 0.0438 m
3
/sec.
1 cubic meter per second = 35.315 ft
3
/ sec. (cfs)
= 2118.9 f3/min (cfm)
= 22.83 x 10
6
gals/d.
= 70.07 Ac.ft/d.
