Skip to main content

Short note: River intake

Short answer

A river intake draws water through ports at different levels fitted with screens, gates, an intake tower, and a pipe to the pump well or treatment plant. Types are wet and dry. Ports at two or three levels with low entrance velocity avoid silt, while coarse and fine screens keep out debris.

Write a short note on river intake.

A river intake is a structure built in a river (or on its bank) to draw water for a water supply scheme. It has ports at different levels, screens, gates or valves, an intake well or tower, and an intake pipe or conduit to the pump well or treatment plant.

   Foot bridge
  =========|===========
           |   Intake tower
 HFL ~~~~~ |  [ ]  gate/valve
           | __|__ upper port
 NWL ~~~~~ |/  |  \  <-- screens
           |   |__ middle port
 LWL ~~~~~ |   |
           |___|__ lower port
  River bed ///|\\\
              \|/ intake pipe to
                   pump well/treatment

Types

  • Wet intake: the tower is filled with water; valves are operated from the top.
  • Dry intake: the tower is dry; water flows through ports to a separate sump and valves are operated in the dry chamber.

Important features

  • Ports at two or three levels give the clearest water in any season; bell-mouth entries and low entrance velocity (0.15 to 0.3 m/s) avoid drawing silt and debris.
  • Coarse (20 to 50 mm) and fine screens (6 to 12 mm) keep out floating matter and fish.
  • The structure is placed in a straight or outer bend reach with a stable bank and enough depth, upstream of pollution sources, and is made safe against floods and scour.
  • Protection works (pitching, groynes) and a foot bridge for access are provided.

Maintenance: regular raking and cleaning of screens, inspection of gates and valves, and flushing silt from the well and pipe.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Water Supply Engineering chapter 5 questions →