The chemical status of the surface water bodies is assessed as being good or failing to achieve good chemical status. The assessment of the chemical status for the third river basin management plan is based on the list of substances of directive 2008/105/EC and the environmental quality standards established by the new directive 2013/39/EC. The assessment without the ubiquist substances permits to get a differentiated picture of the actual situation.

Phytoplancon is one of the 4 biological quality elements (BQE) used for the assessment of the ecological status of the surface water bodies. The assessment is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). The evaluation of this BQE is only relevant for the large rivers where the quantity of phytoplancton is significant and can be evaluated. Therefore phytoplancton is assessed in natural water bodies of type VI an in heavy modified waterbodies (HMWB) presenting a lake character, as the HMWB Sûre (WB III-2.2.1) and the HMWB Our (WB V-1.2). The frequency for phytoplancton monitoring is annually with 6 samples between April and October.

The overall evaluation of the biological status per surface water body is based on the evaluation of the biological quality elements (BQE) : phytoplantcon, aquatic flora, macroinvertebrates an fish. In order to determine the overall evaluation of the biological status per surface water body the worst status assessed by the different biological quality elements ist retained („One out - all out“ principle).

Macrophytes and phytobenthos (diatoms) are two sub-elements of the biological quality element (BQE) of the aquatic flora used for the assessment of the ecological status/potential. The assessment of the aquatic flora is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). The aquatic flora ist assessed following the sub-element the less good (worst-case).

Macrophytes are a sub-element of the biological quality element (BQE) of the aquatic flora used for the assessment of the ecological status/potential. The assessment is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). Macrophytes are particularly sensitive to organic pollution, trophy and hydromorphology.

Phythobenthos (Diatoms) are a sub-element of the biological quality element (BQE) of the aquatic flora used for the assessment of the ecological status/potential. The assessment is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). The diatom assemblages are different in function of concentrations of nutrients and organic pollutants.

Macroinvertebrates are one of the 4 biological quality elements (BQE) used for the assessment of the ecological status of the surface water bodies. The assessment is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). Macroinvertebrates are sensitive to the hydromorphology, water quality, biological continuity , water regime and acidification.

Fish are one of the 4 biological quality elements (BQE) used for the assessment of the ecological status of the surface water bodies. The assessment is made in 5 classes : high (blue) - good (green) - moderate (yellow) - poor (orange) - bad (red). Fish are sensitive to the hydromorphology, water quality, biological continuity and water regime.

Riverbanks improvement by permanent removal of heavy stabilization techniques or by their replacement with plant engineering solutions, in order to recreate near-natural riverbanks with typical vegetation and diversified structures, thus creating microhabitats for aquatic flora and fauna.

Typical river restoration technique. Re-meandering and restoration of the riverbed in order to recreate a new meandering course compliant with the river typology, with a riverbed and riverbanks rich in structures.