Drainage coefficient ($D_c$) is the depth of water (in cm or inches) removed from the drainage area in 24 hours (1 day).
Discharge $Q = 0.2\text{ m}^3/\text{s}$
Volume of water drained in 24 hours:
Drainage Area $A = 250\text{ ha} = 250 \times 10,000 = 2,500,000\text{ m}^2$
Depth of water removed ($D_c$):
जल निकासी गुणांक ($D_c$) 24 घंटे में जल निकासी क्षेत्र से हटाई गई जल की गहराई है:
$$D_c = \frac{0.2 \times 86400\text{ m}^3}{250 \times 10000\text{ m}^2} = 0.006912\text{ m} = 0.69\text{ cm}$$