Vertical drainage: Relies on deep tubewells or pumping wells to extract excess groundwater from deep semi-confined or unconfined aquifers and lower waterlogged water tables -> (IV).
Stuffing box: A mechanical component on the shaft of a centrifugal pump containing packing rings to prevent liquid leakage from pump casing -> (III).
Diffuser: A stationary casing ring with expanding guide vanes fitted in deep-well turbine pumps to efficiently convert the kinetic energy of water leaving the impeller into pressure head -> (II).
Groundwater recharge: The natural or artificial replenishment of groundwater through deep percolation of surface water -> (I).

Rainguns (giant sprinkler guns) operate at high pressures ranging from 3.0 to 9.0 $\text{kg/cm}^2$ (approx. 300 to 900 kPa or 30 to 90 m pressure head). At this operating pressure, they deliver high discharge rates of 200 to 1,200 L/min and cover a wetting diameter of 50 to 120 meters.