Ecological status

Assessment of the structure and functioning of aquatic ecosystems associated with surface waters. It is based on criteria called quality elements which can be biological (presence of living plants and animals), hydro-morphological and physico-chemical. The ecological status has five classes: very good, good, fair, poor and bad. For each type of water body, it is characterized by a deviation from reference conditions (conditions representative of surface water which is not or very little influenced by human activity). The "very good" ecological status is defined by very small differences due to human activity compared to the reference conditions of the type of water body considered. The "good" ecological status is defined by small deviations due to human activity compared to the reference conditions of the type of water body considered. The limits of the good status class are established by inter-calibration.