Diskription and aims

According to the Water Framework Directive (WFD) of the European Community (EC), new procedures for the evaluation of the ecological quality of the surface waters were developed in the last years. By means of these procedures, all EC-states are supposed to evaluate waters, meeting the criteria of appendix 5 of the WFD.

Forreststream. Bild vergrößern Forreststream

The biological assessment procedures are reference-based. This means, that the biocoenosis of every evaluated waterbody has to be compared with the biocoenosis of the so called reference conditions of a water body type. Water body types group biocoenoses. For each type, unloaded and to the greatest possible extent unaffected waters (reference sites) serve as an example (reference).

Diatom. Bild vergrößern Diatom

To assess eckological quatity the following four groups of organisms will be used as indicators:

  • phytoplancton: single-cell algae or diatoms, floating in the water - e.g. as an indicator for the nutrient content of the midwater
  • macrophytes & phytobenthos: aquatic plants and periphyton algae - e.g. as an indicator for the nutrient content of water and sediment, light and discharge conditions
  • macrozoobenthos: on the ground of running waters living invertebrates, like larvae, worms, cancers etc. - e.g. as an indicator for the oxygen content of the water
  • fish e.g. as an indicator for the hydro-morphology

The quality clement of benthic flora "makrophytes & phytobenthos" includes higher aquatic plants, algae, mosses, and water ferns (summarized as makrophytes), along with periphyton algae inclusive diatoms (summarized as phyto-benthos).

macrophytes (aquatic plants) in running waters. Bild vergrößern Macrophytes (aquatic plants) in running Waters

For the assessment of a water, its macrophyte and phytobenthos society has to be compared with the reference society of the same type of water body: The more reference species (and the less degradation species) are found, the merrier is its ecological status. And the more the species composition of the two societies deviate, the more distinct is the degradation of the examined waters section – and the worse the ecological status class. For this analysis step, a software is available. This software in German contens a readme, setup, help, example and data file (link see below).

The new instructions (instruction protocol for standardized sampling and evaluation according to the WFD) and forms (field protocols) will be revised frequently. The complete assessment procedure will be reviewed and adapted if necessary.

Additonal to this there is more literature in German and Englisch available.