- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 06 Oct 2020
Alluvium is loose soil or sediments (such as clay, silt, sand, gravel and so on) that is eroded and carried in suspension by flood or river water before being deposited. The material of alluvium is may be unconsolidated, i.e. not formed together into solid rock, and can by picked up or eroded and carried away by moving water before being deposited elsewhere when the water flow slows down. Where the loose alluvial material is consolidated into a stone-like material (or lithological unit), this is known as lithification.
Some of the characteristics of alluvial soils include:
- The soil morphology will vary according to the age of the alluvial deposit and how it was formed.
- The textural range of the soil can vary widely from gravel to silty clay.
- Drainage can vary from very poor to free.
- The texture of the soil can vary both vertically and laterally.
- It may contain a large amount of organic matter.
The presence of alluvial deposits may mean that the ground conditions are poor and so can require the construction of a raft foundation, or deep pile foundations. In these conditions, strip or pad foundations would require significant excavation.
 Related articles on Designing Buildings Wiki
Featured articles and news
Creating comfortable climates despite extreme temperatures.
Study examines how adjustable arrangements can succeed.
Government announces plans to improve accessibility.
Resource addresses pandemic-related NEC4 contract issues.
Incorporating EDI into the provision of fair access.
Government announces global innovation strategy.
An architectural biography. Book review.
The house where the future king of France lived.
The teacher, architectural technologist and mum offers her insights.
Careful planning needed as supply chain issues continue.
The sensitive conversion of a neglected Cornwall structure.
Plan stresses local involvement in city, town and village development.