3.     Ecological status and potential

3.1.    Introduction

Water Framework Directive (WFD) defines “Ecological status” as the quality of the structure and functioning of aquatic ecosystems associated with surface waters.  Ecological status results from assessment of the biological status of all WFD biological quality elements (fish, macroinvertebrates, phytoplankton, phytobenthos, macrophytes) and the supportive physico-chemical parameters (general and specific ones).  According to ecological status water bodies can be classified into five categories, such as high, good, moderate, poor and bad. 

For heavily modified water bodies (HMWB) and artificial water bodies (AWB) WFD defines “Good ecological potential” status.   Ecological potential includes the same biological and physico-chemical components and reflects given hydromorphological changes. Ecological potential is assessed for heavily modified as well as artificial water bodies and aims for alternative environmental objectives than ecological status.  Both ecological status and ecological potential for surface water bodies are assessed on the basis of specific typologies and reference conditions

The ecological classification system required under the WFD describes hydromorphological elements as 'supporting the biological elements'. This means assessing pressures and impacts on:

• ·         hydrological regime (quantity and dynamics of flow, connection to groundwater);
• ·         continuity (ability of sediment and migratory species to pass freely up and down rivers and laterally with the floodplain);
• ·         morphology (i.e. physical habitat – compositions of substrate, width/depth variation, structure of bed, banks and riparian zone).

 Figure title missing

Source: France Hydromorphology http://www.documentation.eaufrance.fr/entrepotsOAI/AERMC/R156/66.pdf

 Each of the four surface water categories is ascribed specific hydromorphological quality elements (Table 3.1).

• ·         Rivers - depth and width variation; structure and substrate of the river bed; structure of the riparian zone; river continuity.
• ·         Lakes - depth variation; quantity, structure and substrate of the bed; structure of the lake shore.
• ·         Transitional waters (estuaries) - depth variation; quantity, structure and substrate of the bed; structure of the intertidal zone.
• ·         Coastal waters - depth variation; structure and substrate of the coastal bed; structure of the intertidal zone.

Table 3.1: Hydromorphological quality elements to be used for the assessment of ecological status or potential based on the list in WFD Annex V. 1.1.

3.1       Comparison of ecological status and potential of natural, HMWB and AWBS

3.1.1.      Key messages

• ·         More than half of surface water bodies in Europe are reported to be in less than good ecological status or potential
• ·         Only few heavily and artificial water bodies have been classified as having high ecological status (blue colour)
• ·         The overall ecological status/potential are generally better for the natural water bodies compared to the heavily modified and artificial water bodies:
  • Nearly half (48 %) of the natural river water bodies have at least good ecological status, while only 16 % of the heavily modified and artificial river water bodies have good ecological potential.
  • More than 60 % of the natural lake water bodies have at least good ecological status, while only 28 % of the heavily modified and artificial lake Water bodies have good ecological potential.
  • Around 40 % of the natural transitional water bodies have at least good ecological status, while less than 30 % of the heavily modified and artificial transitional water bodies have good ecological potential.
  • More than half (53 %) of the natural coastal Water bodies have at least good ecological status, while one third (35 %) of the heavily modified and artificial coastal water bodies have good ecological potential.

 3.1.2.      Assessment

Overall, more than half (55 %) of the total number of classified water bodies in Europe are reported to have less than good ecological status/potential (EEA 2012: Thematic Assessment: Ecological and chemical tatus and pressures). All these water bodies thereby need management measures to restore their ecological status or potential to fulfil the WFD objective. A higher proportion of water bodies with moderate or worse ecological status or potential are reported for rivers and transitional waters (60-70 %) than for lakes and coastal waters (40-50 %).

There are only a few river heavily modified surface water bodies which have been classified as high ecological status, while no artificial water bodies of rivers or lakes are having high ecological status (Figure 3.1).

The overall ecological status or potential is generally better for the natural water bodies compared to the heavily modified and artificial water bodies. Nearly half (48 %) of the natural river water bodies have at least good ecological status, while only 16 % of the heavily modified and artificial river water bodies have good ecological potential.

Figure 3.1: Ecological status or potential of natural and heavily modified (HMWB) and artificial water bodies (AWB).

Note: Based on water bodies with classified ecological status or potential (water bodies with unknown status not included).

More than 60 % of the natural lake water bodies have high or good ecological status, while only 28 % of the heavily modified and artificial lake water bodies have good ecological potential status.

Around 40 % of the natural transitional water bodies have at least good ecological status, while less than 30 % of the heavily modified and artificial transitional water bodies have good ecological potential (Figure 3.1).

More than half (53 %) of the natural coastal water bodies have at least good ecological status, while one third (35 %) of the heavily modified and artificial coastal water bodies have good ecological potential.

38% of classified coastal waters are in moderate, poor or bad status, meaning that some management measures will need to be taken to improve their status. 62% of transitional waters are in less than good status.

Ecological potential has been reported for overall 777 transitional and coastal water bodies, and around 50% of them are classified as high or good. When only transitional water bodies are considered alone, 68% of classified transitional waters are in moderate, poor or bad status, which also calls for management measures to improve their status by 2015.

Locations of the hydromorphological pressure influenced costal water bodies with less than good ecological status indicate strong relations with industrialized region coastal zones at Northern Adriatic, Catalonia, North Sea and Northern Baltic Sea as shown on Map 3.1. In case of hydromorphological pressure influenced transitional water bodies with less than good ecological status fewer regions are affected, such as Northern Adriatic, Catalonia and Ireland (Map 3.2).

 Map 3.1: Overall ecological potential of coastal HMWB/AWBs and overall ecological

  Status or potential of natural and unknown coastal water bodies with HYMO pressures.

3.2. Case studies on ecological status and potential

3.2.1.      Case study of ecological status and potential

A case study illustrating ecological status and potential of rivers and lakes to be included. Member States or RBDs are appreciated.

3.2.2.      Ecological status or potential in selected coastal areas

Black Sea region and its catchment (Romania)

In the Black Sea region of Romania, two coastal water bodies are identified as heavily modified and two as natural. Both HMWBs are located along ports (Constanța and Mangalia). Coastal water bodies have moderate status/potential except for HMWB in long narrow coastal bay (about 7 km) along Mangalia with bad potential. Two natural transitional water bodies are designated in the Danube Delta with lagoons along the northern part of the Black Sea coast of Romania. They are of poor and bad status respectively. Ecological status/potential of freshwater water bodies close to the coastline is manly moderate. 

Baltic Sea region and its catchment (Germany)

In the Baltic Sea region of Germany, five coastal water bodies are identified as heavily modified. All are located in bays with ports (Kiel, Lübeck, Wismar and Rostock) and accompanying dredging sites. For two HMWBs in Wismar and Rostock, HYMO pressures and impacts have been reported (water flow regulations and morphological alterations of surface water; altered habitats). All HMWBs have poor ecological potential. Other non-modified coastal water bodies that predominate are of moderate to bad status, except for one water body of good status. HYMO pressures were identified for none of natural water bodies despite the ports, dredging and coastal erosion defence works. No transitional water bodies are designated in German part of Baltic Sea region. Ecological status/potential of freshwater water bodies close to the coastline is manly poor to bad status.

 Western Mediterranean Sea region and its catchment (France)

There are many TC water bodies in the Western Mediterranean Sea region of France. Six coastal and four transitional water bodies are identified as heavily modified. In addition, 12 natural transitional water bodies are affected by HYMO pressures and impacts. Coastal HMWBs are located in bays along tourist resorts with ports (Sète, Marseille, Toulon and Nice). They are affected by coastal water management. Four of them suffer HYMO impacts - altered habitats. Four out of six coastal HMWBs have already reached good potential, while other two have moderate potential. Natural coastal water bodies are of good to moderate status with good status prevailing.

Transitional water bodies are located in lagoons and the mouth of the Rhone River and its western branch in the western part of the region. HYMO pressures have been reported for two transitional HMWBs. One of them is used for water abstraction, while other is affected by water flow regulations and morphological alterations resulting in altered habitats. This pressure also affects natural transitional water bodies with HYMO pressures reported. Two transitional HMWBs have reached moderate potential, while two have poor potential. Transitional water bodies that are natural and affected by HYMO pressures have poor to bad status, except for two water bodies with good and moderate status respectively. Ecological status of other natural water bodies ranges from good to bad. Ecological status/potential of freshwater water bodies close to the coastline is manly good to moderate.

Figure 2.7: Ecological status and potential of surface water bodies in three coastal regions.

Note: Map based on WFD Art.13 reporting, Corine Land Cover 2006 and Eurosion data.