Gravity Wells:

In gravity well, the surface of the water outside and surrounding the well is at atmospheric condition. The flow of ground water in such a well under equilibrium condition is given by:

Q =1.36 K (H²- h²)/Log (R)/ (r)

where, Q = Rate of flow into well in m³/d,

K = Permeability constant in m/d,

H = Depth of water in the well before pumping in meter,

h = Depth of water in the well after pumping

= (H - drawdown) in meter,

R = Radius of influence in meter, and

r = Radius of well in meter.

Figure: Gravity Well under Equilibrium Condition