Restoration of the ecological continuity for fish, macroinvertebrates, sediments and terrestrial animals by any transversal structure, through complete or partial removal of that structure, or by adding a fish pass if the previous options are not feasible.

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).

According to the water framework directive WFD (DIR 2000/60/CE), important physico chemical parameters are measured in the surface water bodies for the assessment of the ecological status. The modalities for this monitoring are stated in the grand ducal Regulation of 15 January 2016 (règlement grand-ducal du 15 janvier 2016 concernant l'évaluation of the dimension d'eau de surface). General physico-chemical parameters are used together with the river basin specific pollutants for evaluation of the ecological status.

River protection against the impact of adjacent land use (agricultural runoff such as nutrients and pesticides, fine sediments, cattle trampling, erosion, etc.) through the establishment of fenced riparian buffer stripes, free from any use, where a typical riparian vegetation will grow and provide shade for the river.

River basin specific pollutants are substances that enter the river basin or parts of it in significant quantities. The quantitative assessment is done with environmental quality standards that are fixed by the European Union member states. In Luxembourg, the substances and limit values (annual average) are fixed in the grand ducal regulation of 15 January 2016 (règlement grand-ducal du 15 janvier 2016 concernant l'évaluation des masses d'eau de surface). Evaluation takes place with 2 categories (good, moderate and worse). River basin specific pollutants are used together with the general physico-chemical parameters for evaluation of the ecological status.

According to the water framework directive WFD (DIR 2000/60/CE), important physico chemical parameters and river basin specific pollutants are measured in the surface water bodies for the assessment of the ecological status. The modalities for this monitoring are stated in the grand ducal Regulation of 15 January 2016 (règlement grand-ducal du 15 janvier 2016 concernant l'évaluation of the dimension d'eau de surface).

Overall evaluation of the hydromorphological status per surface water body. The assessment of the hydromorphological status is based on the mapping and the assessment of the structural quality of the Luxembourgish watercourses. The quality elements which have been covered in the framework of the structural quality mapping are: morphology, continuity and hydrological regime. The hydromorphological status is assessed in 5 classes. It is a “pessimistic assessment” because only the worst of the three parameters morphology, continuity and hydrological regime is retained.

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.

Restoration of near-natural flow regime at hydropower plants, discharges and diversions. Adapted operation of hydropower plants, verification and, if necessary, restoration of the natural state of discharge points and verification and possible elimination of water abstractions by means of specific studies of alternative solutions and proposals for mitigation measures.

The "good ecological potential" is the environmental quality objective defined by the water framework directive for artificial and heavily modified surface water bodies. The assessment of the ecological potential is presented in four classes ranging from 1 to 4 (good and higher, moderate, poor, bad). The classification of the ecological potential is based on the biological, physico-chemical and in some cases also the hydromorphological quality elements.