What is a state?

The condition of the system under study (e.g. water body) resulting from both natural and anthropogenic factors (i.e. physical, chemical and biological characteristics).


Benchmark Indicators ?

For a streamlined analysis of multi-stressor effects across the different spatial scales and environmental conditions targeted in MARS, so-called Benchmark Indicators were selected based on a questionnaire circulated to MARS partners (MARS Deliverable 2.1).

The proposed indicators are known to respond to anthropogenic pressure. They are applicable in various geographical contexts and to different water categories and types of water bodies. They generally do not require acquisition of specific data, but refer to data already available. The Benchmark Indicators have to meet certain selection criteria such as general applicability, data availability as well as policy and public awareness.

The table below presents the biological, hydro-morphological and physico-chemical quality elements and state indicatores according to Annex V of the EU Water Framework Directive (WFD). Most of the Benchmark Indicators represent the ‘classical’ state indicators applied in WFD-related water management, some of which also cover abiotic state variables acting as direct pressures impacting on the biological state (e.g. total phosphorus concentration).


State indicators


Quality elements

WFD state indicators and Benchmark Indicators









Composition, abundance and biomass of phytoplankton

Aquatic Flora

Composition and abundance of macrophytes and phytobenthos

Benthic invertebrates

Composition and abundance of benthic invertebrate fauna

Fish fauna

Composition, abundance and age structure of fish fauna








Presence of transversal migration barriers


Quantity and dynamics of water flow

Connection to groundwater bodies

Water residence time


Depth and width variation

Structure and substrate of the water body bed

Structure of the water body shoreline

Tidal regime

Freshwater flow

Wave exposure








Acidification status

Nutrient conditions

Oxygenation conditions


Thermal conditions


Priority hazardous substances

Pollution by all priority substances identified as being discharged into the body of water

Other pollutants

Pollution by other substances identified as being discharged in significant quantities into the body of


MARS Deliverable 2.1: Framework to select indicators of multi-stressor effects for European river basin management (Download report, 780kb)

Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the Community action in the field of water policy (Annex V)  (Download report, 858kb)