Hydraulic turbines selection by head range: choose the turbine for very low heads (0–25 m) Given a site with an available water head in the range of 0 to 25 m. Which turbine type is generally preferred for high discharge and low head conditions? Choose the correct option.

Concept / Approach
Typical head ranges: Pelton (high head, low flow), Francis (medium head), Kaplan/propeller (low head, high flow).

Reasoning
For heads 0–25 m with large discharge, axial-flow Kaplan turbines are preferred due to adjustable runner blades that maintain high efficiency at low heads.

Common pitfalls
Confusing Francis (medium head ~25–250 m) with Kaplan (low head) or Pelton (very high head).

Final Answer
Kaplan turbine.