About assessing aquatic vegetation

This parameter is part of the newly defined UK National Protocol as part of CaSTCo. This description is preliminary and will be updated shortly.

Aquatic plants and algae are important indicators of river habitat health. A diverse mix of submerged, floating, and emergent plants often provides better habitat for wildlife and indicates healthier ecological condition. Small amounts of thin, benthic algae (benthic = attached to the bottom) are an important part of a diverse habitat, but excessive algae can indicate nutrient enrichment.

For each vegetation type, tick one box showing how much of the survey area it covers: Not visible (perhaps due to deep or murky water), absent (would be visible, but isn’t there), less than 5% coverage, between 5% and 33% coverage or over 33% coverage.

The survey area that is assessed will depend on what is realistically visible from your vantage point. Aim to assess full channel width, and up to 5m along the channel or 2 x channel width – whichever is smaller. E.g. if channel is 1m wide then assess area 1m wide by 2m long; if the channel is 10m wide then assess an area 10m wide by 5m long.

Visual aid to estimating % area of coverage