---
title: "Headworks sketch, regulator section, protection works"
subject: "Irrigation and Drainage Engineering"
chapter: 7
key: "semester_6/irrigation_and_drainage_engineering:headworks-sketch-regulator-section-dissipators"
source: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/headworks-sketch-regulator-section-dissipators
site: BCT Engineering
---

# Headworks sketch, regulator section, protection works

Irrigation and Drainage Engineering · Chapter 7: Regulating Structures

- Asked in: 2072 Magh, 3+3 marks
- Video: [COMPONENTS OF DIVERSION HEADWORK | ANIMATED VIDEO LECTURE | GATE | ASSISTANT ENGINEER | SUB ENGINEER](https://www.youtube.com/watch?v=oBisIdBDcLo) — Amaze Academy for Civil Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/headworks-sketch-regulator-section-dissipators
- Whole chapter: https://www.bctengineer.com/md/semester_6/irrigation_and_drainage_engineering/chapter-7

## Question

Drawing a neat sketch of an irrigation headworks, draw a longitudinal section through a head regulator showing upstream floor, regulator gates; energy dissipaters and protection works.

## Short answer

An irrigation headworks includes weir, undersluice, divide wall, head regulator, silt excluder, and guide bunds. Head regulator longitudinal section has upstream floor with cut-off, gated raised crest, stilling basin with chute blocks as energy dissipaters, and downstream inverted filter with stone apron for protection.

## Answer

#### Sketch of an irrigation headworks (3 marks)
```text
              River flow --->
 left  ___________________________________  right
 bank |  Left  |  Weir/Barrage | Under- |  Right
 -----|  guide |  bays (gated) | sluice |  guide
      |  bund  |===============|========|  bund
 Head |regul-  |               | Fish   |
 reg. |ator    |<-silt excluder| ladder |
 -----+--------+---------------+--------+------
 canal                       Marginal bund
```
The components are the weir or barrage, undersluice (with divide wall), canal head regulator, silt excluder, fish ladder and guide bunds with marginal bunds.

#### Longitudinal section through the head regulator (3 marks)
```text
 Pond level ~~~~~~~~~|G|~~~~~~~~~~ canal FSL ~~~~~
 u/s cut-off  u/s apron | crest  | d/s floor | d/s
  ___|________ _________|__gate__|___________|cutoff
 |   upstream floor     raised     stilling basin
 |                      crest      with chute blocks
 |___ impervious floor ________|_ inv. filter _|apron_
```
- **Upstream floor:** impervious, with cut-off, to reduce uplift and exit gradient.
- **Regulator gates:** vertical lift gates between piers on a crest raised above the river bed.
- **Energy dissipaters:** stilling basin/cistern with a hydraulic jump, with chute blocks and end sill, d/s of the gates.
- **Protection works:** inverted filter, loose stone apron and d/s cut-off to protect against scour and piping.

## Check yourself

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

1. Which is among the headworks components?
   A. Only a canal fall
   B. Only an outlet
   C. A sarda fall and escape only
   D. Weir or barrage, undersluice, head regulator, silt excluder, fish ladder and guide bunds
   Answer: D. These are the standard headworks components. (Key point: Headworks components)

2. What is the purpose of the upstream floor with cut-off?
   A. Reduce uplift and exit gradient
   B. Dissipate energy
   C. Support gates
   D. Store silt
   Answer: A. It lengthens seepage. (Key point: Upstream floor)

3. What dissipates energy below the regulator gates?
   A. Cut-off
   B. Stilling basin with a hydraulic jump, chute blocks and end sill
   C. Fish ladder
   D. Guide bund
   Answer: B. Protection then follows with filter and apron. (Key point: Dissipators)

## Related in Irrigation and Drainage Engineering

- [Longitudinal section of a head regulator](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Ahead-regulator-longitudinal-section) — Irrigation and Drainage Engineering, chapter 7
- [Canal head regulator design, Q 150](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Acanal-head-regulator-design-q150) — Irrigation and Drainage Engineering, chapter 7
- [Functions of head and cross regulator](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Ahead-cross-regulator-functions-sketch) — Irrigation and Drainage Engineering, chapter 7, asked 6×
- [Head regulator; outlets and escapes](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Ahead-regulator-outlet-escape-importance) — Irrigation and Drainage Engineering, chapter 7, asked 2×
- [Functions of head regulator, cross regulator, escape](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Ahead-cross-regulator-escape-functions) — Irrigation and Drainage Engineering, chapter 7
- [Stepwise design of head regulator](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Ahead-regulator-design-steps) — Irrigation and Drainage Engineering, chapter 7

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- [Series regulator stability factor and overload protection](https://www.bctengineer.com/question.md?key=semester_3%2Felectronics_devices_and_circuit%3Aseries-regulator-stability-overload) — Electronics Devices and Circuit, chapter 6