---
title: "Geomorphology in searching construction materials"
subject: "Engineering Geology II"
chapter: 7
key: "semester_4/engineering_geology_ii:geomorphology-construction-materials"
source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/geomorphology-construction-materials
site: BCT Engineering
---

# Geomorphology in searching construction materials

Engineering Geology II · Chapter 7: Geology and Construction Materials

- Asked in: 2079 Jestha, 2 marks; 2081 Chaitra, 1 marks; 2073 Magh, 3 marks; 2071 Bhadra, 3 marks (asked 4 times)
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/geomorphology-construction-materials
- Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-7

## Question

Highlight the major application of geomorphology in searching for construction materials.

## Short answer

Geomorphology identifies landforms that contain specific materials: river terraces for sand and gravel, alluvial fans for boulders, talus slopes for rock fill, and bare ridges for quarry sites. It also helps avoid hazards like landslides and floods, reducing exploration costs.

## Answer

**Geomorphology** is the study of landforms and the processes shaping them. Because each landform has a typical material, it directs the search for construction materials.

#### Major applications
1. **River deposits:** active channels, bars and floodplains give sand and gravel; **river terraces** give thick, dry, well-graded sand, gravel and boulders above flood level, suitable for exploitation.
2. **Alluvial fans and debris cones:** coarse material (boulders, cobbles) at the mouths of tributaries.
3. **Glacial and periglacial landforms:** moraines and outwash plains in high Himalaya give mixed boulders and gravel.
4. **Colluvial and talus slopes:** angular rock fragments at the foot of cliffs for rip-rap and rock fill, but variable in quality.
5. **Hill ridges, scarps and outcrops:** show rock exposed at surface with little overburden, ideal for quarries; the slope and relief indicate quarry bench design.
6. **Weathering mantle and residual soil:** thick residual soil gives clay and earth fill; fresh rock is shallow where erosion has been strong.
7. **Drainage pattern and slope:** show lithology, fractures and structure and help in locating accessible, safe sites away from landslides and floods.
8. **Hazard recognition:** old landslides, active gullies and flood plains are identified from landforms so that unsafe sites are avoided.

Thus geomorphological mapping (with aerial photos) cuts the cost and time of exploration.

## Check yourself

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

1. Why are river terraces valuable sources?
   A. They hold fresh quarry rock under thin soil
   B. They are the main source of clay
   C. They give thick, dry, well-graded sand, gravel and boulders above flood level
   D. They are always poor quality
   Answer: C. Terraces lie above flood level and contain well-graded alluvium. (Key point: River terraces)

2. Which landform-material pairing is correct?
   A. Talus slopes give angular rock fragments for rip-rap and rock fill
   B. Moraines give fine uniform clay
   C. Alluvial fans give only fine silt at the apex
   D. Floodplains give fresh bedrock outcrops
   Answer: A. Talus is angular debris at cliff foots, though variable in quality. (Key point: Landform to material)

3. How does geomorphology help with safety?
   A. It guarantees any site is stable
   B. It measures density of the material
   C. Landforms reveal old landslides, active gullies and flood plains so unsafe sites are avoided
   D. It replaces laboratory tests
   Answer: C. Recognising hazardous landforms keeps borrow sites away from danger and reduces exploration cost. (Key point: Hazard recognition)

## Related in Engineering Geology II

- [Topographical and geological maps for materials](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Amaps-construction-materials) — Engineering Geology II, chapter 7, asked 7×
- [Define reserve and estimate construction material](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Adefine-reserve-estimation) — Engineering Geology II, chapter 7, asked 10×

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