Specific ecosystem of aquatic environments generally described by the living beings that are part of it, the nature of the bed and river banks, the characteristics of the catchment area, the hydraulic regime, and the physical-chemical characteristics of water.
Structure in concrete, earth or rock, or a mere (compacted or not) earthen dike or levee for: channelling a stream and possibly protect its surroundings (floodplain) against flooding, and/or protect a defined objective, more or less specific (urban, industrial, agricultural) and sometimes surround it, and/or serve as a barrier for a water abstraction in the stream.
Is known to be achieved for an ecosystem when its abiotic and biotic native components (plants, animals and other organisms) and processes (such as growth and reproduction) or the development of biogeological and natural cycles are intact (dunes or river banks, clearings and edges that are not fixed, etc). For English people, this concept is often called a "healthy ecosystem", that the Water Framework Directive 2000/60/EC refers to as "good