Plastiras lake: the impact of water level on the aesthetic value of landscape

The Plastiras Lake is an artificial reservoir created in 1959 for hydroelectric production. Following different changes in the social, economic and physical context of the area, the water of the lake has been used mainly for irrigation and drinking water supply. Recently, the beautiful scenery of the lake has been considered attractive by visitors and therefore the area has seen a significant touristic development. However, because of the water release mainly for agricultural, but also for hydroelectric purposes, the surface level of the lake varies significantly in the range between the lowest level of 776 m and the overflow level of 792 m. The result is a considerably negative impact on the landscape. The aesthetic value of the scenery has been assessed by a research team through field visits, landscape visual examination, photographic recording, digital image processing, as well as with a survey among visitors. It has been noticed that the most important impact from the level variation is the development of a dead-zone around the lake shore. This zone has different characteristics in the northern and in the southern part. The analysis of the form and size of the dead-zone may provide a concrete assessment of the aesthetic impact, although a quantified approach remains difficult. Moreover, information from the survey gives a significant, yet subjective, estimation of the aesthetic impact. The inhabitants, the regular and the occasional visitors are partially in agreement that the scenery is significantly more valuable when the water level is around 786 m or higher, as compared to when it is around 782 m or lower. If the conservation of the environment and the touristic development of the area are priority objectives, the management of water release through the establishment of a lower limit for the surface level appears to be mandatory.