If EGL = 28 m and velocity head = 6 m, what is HGL?

• A. 22 m
• B. 34 m
• C. 6 m
• D. 28 m

Answer: (A)

The key idea is how energy heads are split along a flow. The energy grade line (EGL) represents the total head: elevation head plus pressure head plus velocity head. The hydraulic grade line (HGL) represents the static head: elevation plus pressure, excluding the velocity head. So along a pipe, EGL = HGL + velocity head, which means HGL = EGL − velocity head.

Plugging in the numbers: EGL is 28 m and the velocity head is 6 m. Therefore HGL = 28 m − 6 m = 22 m. The velocity head is the energy due to motion (v^2/2g); removing it leaves the static components.