Channel bed materials

The channel bed is home to a wide variety of animals including aquatic invertebrates, this also makes it an important habitat for fish to spawn and for animals to find food.

Recording the type of substrate and any changes over time helps us to understand some aspects of the health of your survey location. We ask that you only tick up to three boxes in this section, to capture the most common bottom types.

Bedrock = bare exposed bedrock

Boulders = Larger than 25cm (about football size)

Cobble = Approx. 6cm to 25cm (tennis ball size)

Gravel - pebble = Approx. 2mm to 6cm

Sand = Up to 2mm

Silt/clay = Identify by eye - you'll not be able to discern particles