The remaining active floodplain of the Lower Rhine in The Netherlands contains natural water bodies originating from past geomorphological change, such as meander cut-off, as well as numerous artificial water bodies created by human activities, such as the extraction of gravel, sand and clay. In the undisturbed state, floodplain water bodies may be characterised by a high abundance of aquatic and semi-aquatic vegetation. However, aquatic communities have deteriorated over the last century under the influence of pressures such as pollution, eutrophica-tion, desiccation and unnatural summer inundations. Many macrophyte species characteristic of flood-plains have decreased in abundance. According to the EU Water Framework Directive (WFD), the strongly hydromorphologically altered condition of these water bodies signifies them as heavily modified. For this category of lakes, the WFD requires the definition of Good Ecological Potential (GEP), a state only slightly deviating from the Maximum Ecological Potential (MEP). The MEP reflects the reference condition of the closest comparable surface water body type, given the physical conditions that result from artificial or heavily modified characteristics. The GEP is derived from Good Ecological Status (GES) and should be assessed for different biological quality elements, among which is the abundance and composition of the macrophyte flora.
展开▼
