Other rocks, and the logs of dead trees, piled up against it, forming a natural dam that created the lake.

This natural dam ensures that, even during the driest part of the year, the river level stays high.

The water then accumulated until it eventually destroyed this natural dam, creating a secondary flood and disaster.

The quake triggered a landslide that created a natural dam.

When that happened a rock wall was formed called a moraine, a natural dam behind which a lake or pond can form.

The lake is held in place by a natural dam.

A small creek that runs throughout Fairmont, formed a natural dam and backup water built up.

A moraine serves as a natural dam for the lake.

The lake waters are held in place by a natural dam composed of volcanic rock.

A moraine may form a natural dam below a tarn.