Irrigation, Drainage & Pumping Systems

Statement (I) is false: Shaft horse power (SHP) is the power delivered to the pump shaft by the motor or engine. Water horse power (WHP) is the actual hydraulic power transferred to the water. Because pump efficiency $\eta_p = \frac{\text{WHP}}{\text{SHP}} \lt 1.0$ (due to hydraulic, mechanical, and leakage losses in the pump), SHP is ALWAYS GREATER than WHP ($\text{SHP} \gt \text{WHP}$).
Statement (II) is true: For a directly coupled pump (without belt, gear, or pulley transmissions), transmission efficiency is 100%, and the brake horsepower (BHP) of the prime mover is equal to the shaft horsepower (SHP) of the pump ($\text{SHP} = \text{BHP}$).

A perched water table occurs in the vadose (unsaturated) zone of an unconfined aquifer when downward percolating groundwater is intercepted and collected on top of a localized impermeable or semi-impermeable lens (such as a clay layer). It forms a separate, localized saturated zone situated above the main regional water table of an unconfined aquifer.

The Archimedean screw is an indigenous low-lift water lifting device that consists of an inclined spiral cylinder or helical screw inside a tube. It is typically inclined at an angle of 30° to 35° and is used to lift large volumes of water from shallow ditches, drains, or canals through small lifts ranging from 0.5 to 1.20 m.

The cut-in wind speed required to start and operate multi-blade agricultural water-pumping windmills typically ranges between 6 to 8 km/hr (approx. 1.6 to 2.2 m/s). Below this threshold, the aerodynamic torque generated by the rotor blades is insufficient to overcome static mechanical friction and the load of the pump rod and water column.