EN 16150:2026

Water quality - Guidance on pro-rata multi-habitat sampling of benthic macroinvertebrates from rivers and streams EN 16150:2026

Publication date:   May 18, 2026

Scope

This document gives guidance for pro-rata multi-habitat sampling of benthic macroinvertebrates in rivers and streams. The term "pro-rata" reflects the intention to sample all the main riverine habitats present at a monitoring site according to the proportion of the site that it covers. It is an objective way to divide sampling effort among the different habitats.
This document is applicable to all flowing waters, both artificial, modified and natural. It enables comparable samples to be collected from any type of river, regardless of the habitats present.
This document gives guidance on an overall approach rather than a specific method.
This document is applicable to:
- supporting environmental and conservation agencies, water boards, and water agencies to meet the monitoring requirements of the WFD (Article 8, Annex II, and Annex V) [1];
- generating data sets appropriate for monitoring and reporting of sites designated under the Habitats Directive and the Birds Directive to ensure that samples for comparing the overall composition of invertebrates from different stream types are comparable;
- ensuring samples for environmental quality assessments across different stream types are comparable even when sampled by different people;
- supporting river management and restoration initiatives;
- sampling sites in a consistent way that is not dependent on the presence of particular types of habitat; a user-friendly strategy for collecting biological data depending on the distribution of habitats;
- understanding the distribution of biological community types across different physical river types; and
- assessing quality based on deviation from reference, as adopted in the European Water Framework Directive [1].