what is tmc?often used this trem in measuring the water.?

Answer 1

TMC ft
an abbreviation for "thousand million cubic feet," commonly used in water management in India. One TMC ft is equivalent to about 28.317 million cubic meters or 22 956.8 acre feet. One TMC ft/day is about 11 574 cubic feet per second or 327.74 cubic meters per second.

"TMC" alone doesn't exist.

(following link is a very good reference when dealing with conversion problems from one measure system to another)

Answer 2

Its a measure of volume in metric cube