What is a drumlin?
A drumlin is an elongated, streamlined hill formed by an ice sheet or glacier, made up of glacial till, gravel and sand. Its steep side points to the source of the ice and its gentle slope to the direction in which the ice moved. Drumlins appear in formerly glaciated regions and matter for both building ground and archaeology.
How does a drumlin form?
During the Saalian ice age, vast ice sheets covered parts of northern Europe. Material was carried under the ice and deposited around a hard core, such as an erratic boulder. The flow of the ice gave the deposit its kite-like streamlined shape.
Typical features:
- Length — usually between 100 and 2000 metres
- Width — about a third to half of the length
- Height — typically 10 to 50 metres
- Material — densely packed till, gravel and sand
Application and relevance
- Building ground — drumlins are firmly packed and often have good bearing capacity
- Archaeology — frequently inhabited in the past, with valuable heritage
- Landscape — typical glacial form, often protected
- Road construction — used as viewpoints or alignments
- Recreation — drumlins provide footpaths and viewpoints
Points of attention
- Always carry out a ground investigation before building — till may contain boulders and clay lenses
- Take account of archaeological values during excavation
- Drumlin landscapes are often protected by regulation
- Drainage can be complex due to variable soil composition
- Slopes require care for falls and stability
Related terms
- Building ground
- Building plot
- Ground investigation
- Cultural-historic value
- Drainage
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