Special case study of the flowing waters of the Enipea – Xyles watershed of the Prefecture of Pieria. [in Greek] (original) (raw)

The two major innovations of the Directive 2000/60/EC is firstly the fact that examines the water body at a river basin level and secondly the fact that for the assessment of the ecological water quality, apart from the physico-chemical and hydromorphological parameters, some biological parameters are also examined. Taking into account all the aforementioned, the current case study was implemented, in order to evaluate the ecological status of Enipeas – Xyles river basin (May 2013) according to the Water Framework Directive 2000/60/EC. Totally, nine sampling stations were determined for sampling but only in five of them, samples of water, benthic macroinvertabrates and fishes were collected. The water balance was estimated and it was found surplus and additionally there was a determination of the physico-chemical parameters either in the field or in the laboratory. All the values complied with the drinking water limits, whereas an excession was observed concerning the fish life limits. Concerning the river habitats (HMS), six out of the nine stations were identified as obviously to severely modified, apart from the stations Litochoro ananti and Litochoro katanti which were identified as semi natural and the station Stratopedo katanti as predominantly unmodified. Moreover the high elevation, the steep bank inclination, the low temperature and the break of the continuity, have played a significant role in the fact that no fishes were collected in the majority of the stations, except for the station Technito kanali ananti, which is located adjacent to the sea. The benthic macroinvertabrates, as biological index, seem to have an excellent correspondence to the changes of the water quality, which is influenced by the morphological characteristics of the water basin, the vegetation, the various activities that took place inside the basin and finally the location of monitoring stations. Regarding the water ecological status, it was found high at the station Litochoro ananti, moderate at the station Litochoro katanti and poor at the stations Stratopedo katanti and Technito kanali ananti. This significant degradation of the ecological status among the first three stations happens because of the “nitrate pollution” from the agricultural activities. The sampling stations Litochoro katanti (moderate ecological status), Stratopedo katanti (poor ecological status) and Technito kanali ananti (poor ecological potential) are located outside the Natura protected zone, whereas the station Litochoro ananti (high ecological status) is located inside the Natura zone. The hierarchical clustering, has also classified the sampling stations into three different categories according to their ecological status / potential. Furthermore IMPRESS analysis was implemented and it was highlighted intense pressure, originated from the agricultural activities. Taking into consideration the calculations for the IMPRESS analysis in order to determine the pollution load in Enipeas – Xyles river basin, it is noticed a very significant excession of the BOD5, total nitrogen and total phosphorus concentrations, comparing to the fish life limits. Finally, regarding the morphological alteration pressures, the risk of failing the environmental objectives for the entire basin is high and for this reason an additional IMPRESS analysis should be implemented, whereas the risk of failure due to pollution pressures is medium and a long term programme of measures should be established.