---
title: "Role of groundwater in irrigation development"
subject: "Engineering Hydrology"
chapter: 1
key: "semester_5/engineering_hydrology:groundwater-irrigation-role"
source: https://www.bctengineer.com/q/semester_5/engineering_hydrology/groundwater-irrigation-role
site: BCT Engineering
---

# Role of groundwater in irrigation development

Engineering Hydrology · Chapter 1: Introduction

- Asked in: 2067 Shrawan (old course), 6 marks
- Video: [How Wells & Aquifers Actually Work](https://www.youtube.com/watch?v=bG19b06NG_w) — Practical Engineering
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/engineering_hydrology/groundwater-irrigation-role
- Whole chapter: https://www.bctengineer.com/md/semester_5/engineering_hydrology/chapter-1

## Question

Briefly describe the role of ground water in irrigation development.

## Short answer

Groundwater provides a dependable dry-season source when surface water is scarce, enabling supplementary irrigation and increasing cropping intensity. It allows farmers individual control over timing and amount, reduces conveyance losses, and when used conjunctively with canal water prevents waterlogging and salinity.

## Answer

Groundwater is water stored in the pores and fractures of soil and rock below the water table. It is a major, reliable source for irrigation, especially where surface water is limited or seasonal.

#### Role in irrigation development
1. **Dependable dry-season source:** Rivers and canals often carry little water in winter and spring. Wells give water when it is needed.
2. **Supplementary irrigation:** Where canal water is short, tubewells give extra water for the second and third crops.
3. **Terai development:** In Nepal's Terai the shallow aquifer allows shallow tubewells (STW) and deep tubewells (DTW). The Bhabar zone recharges the aquifer.
4. **Individual control:** Farmers can irrigate at the time and amount they need, which raises yields.
5. **Quick and cheaper development:** Small wells need less capital and time than large canal systems, and have no conveyance loss or large land acquisition.
6. **Conjunctive use:** Using surface water and groundwater together lowers waterlogging and salinity by keeping the water table low.
7. **Drought protection:** Stored groundwater reduces the risk of crop loss in dry years.

#### Limits
Over-pumping lowers the water table, energy cost is high, and water quality (salts, arsenic in some Terai districts) must be checked. Pumping should not exceed the recharge.

## Check yourself

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

1. Why is groundwater valuable for irrigation?
   A. Rivers are largest in winter
   B. It is always saline
   C. It gives dependable water in the dry season when rivers carry little
   D. It needs no pumping
   Answer: C. Wells give water when needed. (Key point: Dry season)

2. What does conjunctive use of surface and groundwater do?
   A. Raises water table
   B. Increases conveyance loss
   C. Eliminates canals
   D. Lowers waterlogging and salinity by keeping the water table low
   Answer: D. Pumping lowers the water table. (Key point: Conjunctive use)

3. What is a limit of groundwater development?
   A. Over-pumping lowers the water table and arsenic may occur
   B. It always rises
   C. It has no energy cost
   D. Water quality is never an issue
   Answer: A. Pumping should not exceed recharge. (Key point: Limits)

4. Why are small wells quicker and cheaper?
   A. They need large canals
   B. Less capital and time, no conveyance loss or large land acquisition
   C. They need big dams
   D. They need more land
   Answer: B. Compared with canal systems. (Key point: Cost advantage)

## Related in Engineering Hydrology

- [Water budget equation and its role](https://www.bctengineer.com/question.md?key=semester_5%2Fengineering_hydrology%3Awater-balance-equation-processes) — Engineering Hydrology, chapter 1, asked 5×

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