Skip to main content

Requirements of a good intake; types in Nepal

Short answer

A good intake must pass design discharge without vortices, exclude bed load and trash, have low head loss, be stable, and include gates and flushing. In Nepal common types are side intake, bottom or Tyrolean intake, frontal intake, and reservoir or tunnel intake.

What are the requirements of a good intake? Explain different types of intake used in hydropower projects in Nepal with neat sketches.

Requirements of a good intake

  • Pass the design discharge in all river conditions, with the opening always submerged and no vortex or air entry.
  • Keep out bed load, sediment and floating trash (high sill, trash rack and boom).
  • Low head loss through a smooth, bell-mouthed entry and a short transition.
  • Structurally stable in floods; strong foundation; safe against scour and uplift.
  • Gates for regulation and shut-off, easy to operate; flushing arrangement in front of the intake.
  • Easy access for maintenance and for removal of trash and sediment.
  • Economical, with minimal impact on the environment and fish.

Types of intakes used in Nepal

  1. Side intake (most common): the opening is in the river bank next to the weir; the undersluice flushes the front.
  2. Bottom (Tyrolean) intake: a rack across the stream bed, used in steep streams, e.g. micro and small hydropower projects.
  3. Frontal intake (in the dam or weir face): used rarely.
  4. Reservoir/tunnel intake (submerged): a pressurised tower or inclined rack on a storage project.
 Side intake (plan)        Bottom intake (section)
 ===> weir  |||||||        flow ==> \\\\\\\\ rack
   rack |  gate -->               |____chamber____|-->

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Hydropower Engineering chapter 5 questions →