S_{1} and S_{2} are the draw downs in an observation well at times t_{1} and t_{2} after pumping. For discharge Q and coefficient of transmissibility T, the relationship, is
For the same draw down in two observations wells at distances r1 and r2, the times after start of pumping are t1 and t_{2} hours respectively. The relation which holds good is
If P is population of a city in thousands and Q is fire demand in litres per minute, for proper estimate of water, the Empirical formula `Q = 1135 ( P/5 + 10)` is suggested by
Grade aqueducts are not allowed to run
The formula ` H_L = (n^2 V^2 .L)/(R^(4//3))` for the head loss in conduits is generally known as