Ecological Monitoring, Biological Q Rating / Small Stream Risk Assessment

In the presence of pollution changes are induced in the flora and fauna of rivers, in many cases, the sensitive species are progressively replaced by the more tolerant forms as pollution increases. Biological assessment of the macroinvertebrate community in rivers is one method used to assess the health of an aquatic ecosystem. This assessment is based on the relative abundance of indicator taxonomic groups and the habitat at the sampling sites. A biotic index (Q-Rating) is determined for each site in accordance with the biological assessment procedure used by the Environmental Protection Agency (McGarrigle et al, 2002).

Faunal samples are collected using the “kick sample” method. This method gives a good indication of the diversity and quantity of species present at the site. A two minute “kick sample” and stone wash is carried out within the riffle area of rivers. The samples collected are live sorted and identified to the level required for the EPA Q-rating system. The relative abundance of each taxon recorded is assessed and a Q-rating is assigned.

The Q-Rating system is based on both the habitat and the invertebrate community assessment. Habitat assessments of rivers consists of the following:

  • Stream width and depth
  • Stream flow type (% of riffle, glide and pool)
  • Substrate type and quantification of substrate components
  • Riparian vegetation % cover/shade and species identification
  • Instream vegetation identification and % cover
  • Dissolved oxygen and temperature measurements
  • Visual assessment of water

For more information on this and the other services on offer here at Fitz scientific contact us today on 041 98 45440 ext 1 or email

Key Features

  • EPA Approved Q-ratings
  • Benthic invertebrate, Macrophytes & Hydromorphology
  • Comply with Water Framework Directive
  • Industry Expert Scientists

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