Section 4: Soil and Water Conservation Engineering
Gully Control and Drop Spillways
Subtopic: Drop Inlet Spillways
Question Statement:
A drop inlet spillway (pipe spillway with vertical riser) in an earthen dam or gully plug primarily functions under:
Options:
(A) Weir flow control at low heads, transition flow, and full pipe (orifice/pipe) flow control at high heads
(B) Supercritical open chute flow throughout
(C) Pure Darcy porous media flow
(D) Centrifugal vortex cavitation
Answer Key:
A
Step-by-Step Solution & Explanation
At initial ponding, water spills over the riser lip (weir flow); as head rises, the riser entrance submerges (orifice flow) and eventually the horizontal conduit flows full under pressurized pipe flow.