Anchor Ice – a big hassle for in-stream water quality sensors

anchor ice - Submerged ice attached or anchored to the river bed, irrespective of the nature of its formation. Western Lake Superior streams that lack springs can get so cold in winter that the a lot of ice can form on the bedrock bottom and destroy aquatic life and habitat.

Depending on air temperatures and snow accumulations, the streams monitored in Duluth since 2003 have typically had varying levels of anchor ice in the early winter that has disappeared later in the winter or at least stabilized. In November and December 2005, the sensors were pulled till after New Years day to avoid the chance of the units freezing in and the sensors being damaged.

Tischer Creek Anchor Ice Tischer Creek Anchor Ice

These are from Tischer Creek in November 2003

Amity Creek Anchor Ice

This image is from Amity Creek in December 2005

Anchor Ice – What does it really look like and how does it form?