---
title: "Erosional features of underground water"
subject: "Engineering Geology I"
chapter: 6
key: "semester_3/engineering_geology_i:erosional-features-of-underground-water"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/erosional-features-of-underground-water
site: BCT Engineering
---

# Erosional features of underground water

Engineering Geology I · Chapter 6: Physical Geology

- Asked in: 2076 Asoj, 2 marks
- Video: [Karst Landforms |Erosional and Depositional Features by Ground Water| Geomorphology| Dr. Krishnanand](https://www.youtube.com/watch?v=JNc23Bh4P6k) — TheGeoecologist
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/erosional-features-of-underground-water
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6

## Question

Describe the erosional features developed by underground water.

## Short answer

Groundwater erodes soluble rocks by solution, creating karst topography. Features include sinkholes (dolines), caves, sinking streams, lapies (karren), uvalas, poljes, natural bridges, and dry valleys.

## Answer

Groundwater erodes mostly by **solution**, working on soluble rocks (limestone, dolomite, gypsum). The landscape is called **karst topography**. Features:

- **Sinkholes (dolines):** closed depressions made by dissolution or by collapse of a cave roof.
- **Caves and caverns:** underground hollows enlarged along joints and bedding planes.
- **Sinking streams and underground rivers**, **springs**.
- **Lapies (karren):** grooves and ridges on exposed limestone.
- **Uvala and polje:** large, compound sinkholes and wide valley-like basins.
- **Natural bridges** and **dry valleys**.

## Check yourself

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

1. Groundwater erodes mostly by:
   A. Abrasion
   B. Plucking
   C. Solution
   D. Deflation
   Answer: C. It dissolves limestone etc. (Key point: Process)

2. A sinkhole is:
   A. Ridge of till
   B. Icicle deposit
   C. Sea arch
   D. Closed depression from dissolution or cave-roof collapse
   Answer: D. Also called doline. (Key point: Sinkhole)

3. Lapies (karren) are:
   A. Grooves and ridges on exposed limestone
   B. Large basins
   C. Underground rivers
   D. Cave columns
   Answer: A. Polje is the large basin. (Key point: Lapies)

4. Uvala and polje are:
   A. Small grooves
   B. Large compound sinkholes and wide valley-like basins
   C. Cave deposits
   D. Springs
   Answer: B. Larger scale karst forms. (Key point: Uvala)

## Related in Engineering Geology I

- [Erosional features of glacier and underground water](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aerosional-features-of-glacier-and) — Engineering Geology I, chapter 6
- [Erosional feature of running water and wind](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aerosional-feature-of-running-water) — Engineering Geology I, chapter 6
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