---
title: "Head regulator; outlets and escapes"
subject: "Irrigation and Drainage Engineering"
chapter: 7
key: "semester_6/irrigation_and_drainage_engineering:head-regulator-outlet-escape-importance"
source: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/head-regulator-outlet-escape-importance
site: BCT Engineering
---

# Head regulator; outlets and escapes

Irrigation and Drainage Engineering · Chapter 7: Regulating Structures

- Asked in: 2079 Jestha, 4 marks; 2077 Chaitra, 4 marks (asked 2 times)
- Video: [Canal Regulatory Works | Irrigation Engineering](https://www.youtube.com/watch?v=rYALwx_DJbU) — APSEd
- 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/head-regulator-outlet-escape-importance
- Whole chapter: https://www.bctengineer.com/md/semester_6/irrigation_and_drainage_engineering/chapter-7

## Question

What do you understand by head regulator? State the functions (importance) of outlets and escape structures in an irrigation canal.

## Short answer

A head regulator is a gated structure at an off‑take that controls discharge, silt, and measurement. Outlets deliver equitable and measured shares to farmers; escapes protect canals from overtopping, allow emptying, and remove silt.

## Answer

#### Head regulator (4 marks)
A **head regulator** is a gated structure constructed at the head of an off-taking canal, distributary or minor from a parent canal or river. It admits the required discharge into the off-take and shuts it off when needed.

Functions:
1. Regulates the discharge entering the off-take channel.
2. Controls silt entering the off-take (high crest, silt excluder).
3. Measures the discharge.
4. Closes the supply for repair, flood or when the water is not required.

#### Importance of outlets (2 marks)
An outlet delivers the water from the distributary to the water course (or field channel).
1. It gives the farmers a fixed and equitable share of water.
2. It allows measurement and control of the discharge to each chak (command area).
3. It makes the best use of the available supply and gives equitable distribution.

#### Importance of escape structures (2 marks)
An **escape** is a structure that disposes of the surplus water of a canal into a natural drain or river.
1. Protects the canal against overtopping and breach from sudden excess flow (heavy rainfall or sudden closure of gates).
2. Provides a means to empty the canal quickly for repairs or in an emergency.
3. Removes silt (scouring escape) and disposes of flood water that enters through cross-drainage works.
4. Escapes are placed near the canal head, upstream of major structures and upstream of cross regulators.

## Check yourself

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

1. What is a head regulator?
   A. A gated structure at the head of an off-taking canal that admits the required discharge and shuts it off when needed
   B. A weir across the river
   C. A drain taking surplus water
   D. A fall in the canal
   Answer: A. It regulates entry, controls silt, and measures discharge. (Key point: Head regulator)

2. What is the importance of an outlet?
   A. Disposes of surplus water
   B. Gives farmers a fixed, equitable share and allows measurement and control to each chak
   C. Raises water level
   D. Reduces canal slope
   Answer: B. The outlet delivers from the distributary to the water course. (Key point: Outlet importance)

3. What does an escape do?
   A. Holds water level up
   B. Supplies water to fields
   C. Disposes of surplus canal water into a natural drain, protecting the canal from overtopping and allowing emptying
   D. Measures flow
   Answer: C. Escapes protect against breaches and permit quick emptying. (Key point: Escape purpose)

## Related in Irrigation and Drainage Engineering

- [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
- [Canal escape structures with sketch](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aescape-structure-sketch) — Irrigation and Drainage Engineering, chapter 7, asked 2×
- [Canal head regulator design, Q 200](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Acanal-head-regulator-design-q200) — 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×
- [Types of canal outlets](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aoutlets-types-classification) — Irrigation and Drainage Engineering, chapter 7, asked 4×

## Related in other subjects

- [Irrigation canal earthwork with vertical drop](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Acanal-a-drop-0-400) — Estimating and Costing, chapter 6
- [Irrigation canal earthwork, 0-600 m](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Airrigation-canal-k-drop) — Estimating and Costing, chapter 6