---
title: "Types of intakes and their suitability"
subject: "Hydro Power"
chapter: 5
key: "semester_6/hydro_power:intake-types"
source: https://www.bctengineer.com/q/semester_6/hydro_power/intake-types
site: BCT Engineering
---

# Types of intakes and their suitability

Hydro Power · Chapter 5: Components of Hydropower System

- Asked in: 2071 Magh, 5 marks; 2070 Bhadra, 5 marks (asked 2 times)
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/hydro_power/intake-types
- Whole chapter: https://www.bctengineer.com/md/semester_6/hydro_power/chapter-5

## Question

Explain with neat sketch, different types of intakes and its suitability in hydropower projects.

## Short answer

Six common intake types: side intake (most common in Nepal run-of-river), frontal (low sediment), bottom/Tyrolean (steep streams, micro hydro), tower (reservoirs with large level variation), face/shore (dams), and siphon (small heads). Each suits specific river and project conditions.

## Answer

An **intake** is the structure at the head of a water conductor system that draws the required discharge from a river or reservoir while keeping out floating debris, ice, and as much sediment as possible.

#### 1. Side (lateral) intake
Opening in the river bank at an angle to the flow, usually upstream of a diversion weir.
- **Suitability:** most common in Nepalese run-of-river projects on medium and large rivers. Placing it on the outer bank of a bend reduces bedload entry.

```text
   river flow ---->
 =========================
     |         | weir   |
     |  intake |========|
 ====|  gate   |=========
     v
  to gravel trap / canal
```

#### 2. Frontal intake
Intake facing the flow directly, with the river bed upstream and a sluice for flushing.
- **Suitability:** where the river carries little bedload, or in canal-type schemes; strong flow towards the intake but more sediment entry.

#### 3. Bottom (drop, Tyrolean or trench) intake
A trench with an inclined trash rack set in the weir crest; water drops through the rack into a gallery.
- **Suitability:** steep mountain streams with boulders and coarse bedload, small and micro hydro (common in Nepal's hilly streams).

```text
  flow -->  ___rack___
 ~~~~~~~~~/\/\/\/\/\/\~~~~~~
 =========|  trench  |=====> to canal
          |__________|
```

#### 4. Tower intake
A vertical tower in a reservoir with ports at several levels, connected to a tunnel.
- **Suitability:** storage dams with large fluctuation of water level; allows drawing water from different depths.

#### 5. Shore/face intake (dam intake)
Opening in the dam face or reservoir bank, with trash rack and gate, leading to the penstock/tunnel.
- **Suitability:** concrete dams and pondage schemes (e.g. Kulekhani).

#### 6. Siphon intake
Uses a siphon over the dam crest. Suitable for small heads and small discharges.

| Type | Best suited to |
|---|---|
| Side intake | ROR projects on medium/large rivers |
| Frontal | Low-sediment rivers |
| Bottom/Tyrolean | Steep, bouldery streams; small hydro |
| Tower | Reservoirs with large level variation |
| Face/shore | Dams and pondage schemes |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which intake suits steep mountain streams with boulders and coarse bedload, especially small hydro?
   A. Bottom (Tyrolean) intake
   B. Siphon intake
   C. Frontal intake
   D. Tower intake
   Answer: A. A trench with inclined trash rack in the weir crest passes water down while boulders pass over. (Key point: Bottom intake suitability)

2. A tower intake is suitable for:
   A. Only canal-type schemes
   B. Micro hydro only
   C. Storage reservoirs with large water-level fluctuation, drawing from different depths
   D. Small streams with no storage
   Answer: C. Ports at several levels allow drawing water at different depths as the level changes. (Key point: Tower intake)

3. Where is a side intake best placed to reduce bedload entry?
   A. Outer bank of a bend
   B. Inner bank of a bend
   C. Downstream of the weir
   D. Mid-river
   Answer: A. On the outer bank, secondary currents carry bedload to the inner bank. (Key point: Side intake placement)

4. Frontal intake is suited to:
   A. Reservoirs only
   B. Steep boulder streams
   C. Rivers with little bedload, accepting more sediment entry
   D. Rivers with heavy bedload
   Answer: C. Facing the flow draws more sediment, so it suits low-bedload rivers. (Key point: Frontal intake)

## Related in Hydro Power

- [Flow duration curve and planning parameters](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Afdc-planning-parameters) — Hydro Power, chapter 3
- [Pre-feasibility versus feasibility studies](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Aprefeasibility-vs-feasibility) — Hydro Power, chapter 3
- [Spillway types suitable for Nepalese rivers](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Aspillway-types-nepal) — Hydro Power, chapter 6
- [Spillways, gates and types of spillways](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Aspillways-and-gates) — Hydro Power, chapter 6

## Related in other subjects

- [Common RoR intakes in Nepal; site selection](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aror-common-intakes-nepal-location) — Hydropower Engineering, chapter 5, asked 2×
- [Types of powerhouses and suitability](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Apowerhouse-types-suitability) — Hydropower Engineering, chapter 8, asked 4×
- [Intakes for storage plants](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Astorage-plant-intake-types-arrangement) — Hydropower Engineering, chapter 4, asked 2×
- [Pressurized vs non-pressurized intakes](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aintake-pressurized-vs-nonpressurized) — Hydropower Engineering, chapter 5, asked 2×