Article 4.7: A clause in the WFD which may, under exceptional circumstances, allow an activity to continue even though it causes deterioration in the status of a water body or failure to reach GES or GEP. In order for deterioration to be permitted four tests have to be passed.

Artificial/Heavily Modified Water Body (A/HMWB): A water body that has been altered by human activities. 

Biological Quality Elements: The fish, invertebrates and plants found in a water body. 

Ecology: The plants, animals and habitats of a water body. 

Flood and Coastal Erosion Risk Management (FCRM): The function with responsibility for managing risks from flooding and erosion. 

Flood Defence Consent: A consent for works in, over or under a watercourse, close to the water's edge (river bank top or landward toe of coastal defences), or in land liable to flooding. FDC is granted by the Environment Agency and Lead Local Flood Authorities.

Good Ecological Potential (GEP): The best ecology that can be achieved in an A/HMWB, whilst still allowing human activities to continue. 

Good Ecological Status (GES): The best ecology that can be achieved in a surface water body that has not been modified for a specific use by humans. 

Hydromorphology: The shape, physical characteristics and flow of a water body. 

Internal Drainage Board (IDB): A public authority established in areas of special drainage (in England and Wales) with permissive powers to manage water levels within their respective drainage districts.

Lead Local Flood Authority (LLFA): Unitary authorities or county councils with responsibility for managing flood risk in their geographical area. 

Main river: A larger watercourse that has been identified as being important by Defra. Main rivers are managed by the Environment Agency. 

Mitigation measure: An environmental improvement which helps to address the impacts of human activities on a water body. 

Ordinary watercourse: A river, stream, ditch or drain that is not a main river. Ordinary watercourses are managed by IDBs or LLFAs. 

Quality elements: Components of a water body that can be affected by human activity, such as biology, hydromorphology, water quality and physical processes. 

River Basin Management Plan (RBMP): Plans which describe how the requirements of the WFD will be achieved in your region. 

River Basin Planning Cycle: A six year period during which the RBMPs should be delivered. 

Supporting elements: The hydromorphological, water quality and chemical characteristics which support the biological quality elements.

Transitional water bodies: An estuary. 

Water body: A distinct body of water, including rivers, streams, canals, lakes, reservoirs, estuaries, coastal waters and groundwaters. 

Water Framework Directive (WFD): A European Directive which aims to protect and improve the water environment.