---
title: "Aquifer systems of Nepal"
subject: "Engineering Geology II"
chapter: 3
key: "semester_4/engineering_geology_ii:aquifer-systems-nepal"
source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/aquifer-systems-nepal
site: BCT Engineering
---

# Aquifer systems of Nepal

Engineering Geology II · Chapter 3: Hydrogeology

- Asked in: 2079 Chaitra, 2 marks; 2078 Poush, 1.5 marks; 2078 Baisakh, 1 marks; 2072 Magh, 2 marks; 2069 Bhadra, 2 marks; 2068 Magh, 1 marks (asked 6 times)
- Video: [Types of Aquifer - Ground Water and Well Hydraulics - Water Resource Engineering 1](https://www.youtube.com/watch?v=3FSs53BgGmA) — Ekeeda
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/aquifer-systems-nepal
- Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-3

## Question

Describe the different aquifer systems of Nepal (Terai, hills and mountains).

## Short answer

Terai: thick Quaternary alluvium; Bhabar unconfined coarse aquifer, southern Terai has shallow unconfined and deep confined aquifers. Hills: fractured/weathered rock and springs, intermontane basin sediment aquifers. High mountains: fractures and glacial debris, low yield.

## Answer

An **aquifer** is a saturated geological formation that stores and transmits useful quantities of water. In Nepal, aquifer systems differ by physiographic region.

#### 1. Terai (Indo-Gangetic plain)
- Made of thick Quaternary alluvium (gravel, sand, silt, clay), hundreds of metres thick.
- **Northern Terai (Bhabar zone):** coarse boulder-gravel at the foot of the Churia; very high permeability; unconfined aquifer with deep water table; main recharge zone.
- **Southern Terai:** alternating sand and clay layers; **shallow unconfined** aquifer (up to about 30-50 m) and **deep confined (artesian)** aquifers, with flowing wells in places.
- Highest groundwater potential; shallow tube wells and deep tube wells widely used. Arsenic problem in shallow aquifers.

#### 2. Hills (Siwalik, Mahabharat and Middle Mountains)
- Rock aquifers: fractured and weathered phyllite, schist, quartzite, limestone and Siwalik sandstone.
- Groundwater occurs in joints, fault zones, weathered layer and colluvial/river terrace deposits.
- Yield is low and variable; springs are the main source. Intermontane basins (Kathmandu, Pokhara) have thick lacustrine and fluvial sediments with good confined and unconfined aquifers.

#### 3. High mountains
- Crystalline rocks (gneiss, granite) and glacial and moraine deposits.
- Groundwater only in fractures and glacial debris; snow melt and glaciers are the main sources; springs on slopes. Potential is small and poorly known.

## Check yourself

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

1. What is the role of the Bhabar zone of northern Terai?
   A. Main recharge zone with coarse boulder-gravel and high permeability
   B. Zone of deep clay only
   C. Zone with no groundwater
   D. Glacier region
   Answer: A. Coarse sediments at the Churia foot absorb water and recharge the Terai aquifers. (Key point: Bhabar zone)

2. What aquifer arrangement occurs in the southern Terai?
   A. Shallow unconfined plus deep confined (artesian) aquifers
   B. Only karst
   C. Only fractured rock
   D. No aquifer
   Answer: A. Alternating sand and clay give shallow unconfined and deep confined aquifers. (Key point: Southern Terai)

3. Where does groundwater occur in the hill region, and what is the main source?
   A. Pores of gravel; wells
   B. Joints, fault zones, weathered layer; springs
   C. Glaciers only; lakes
   D. Sea water; wells
   Answer: B. Rock aquifers store water in fractures and weathered layers, and springs are the main source. (Key point: Hills)

## Related in Engineering Geology II

- [Aquifer formation in Terai and mountains](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aaquifer-formation-terai-mountain) — Engineering Geology II, chapter 3, asked 2×
- [Major discontinuity systems of Nepal Himalaya](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Anepal-discontinuity-systems) — Engineering Geology II, chapter 2, asked 12×