Ecological studies on the Kerhni reservoir (N-Greece)

This paper refers to the morphometric and hydrological conditions, as well as to the physical and chemical characteristics of the Kerkini reservoir (N Greece) and determines the trophic status. The flushing rate, and the residence time of the water show clearly the dominance of the riverine system upon the lacustrine circulation pattern. The shallowness of the reservoir, the inflow of river Strimon, and the nearly continuous functioning of the dam throughout the year should be considered as the factors influencing the circulation of the water in the reservoir. Phosphorous mean annual value, mean annual and maximum values of chlorophyll-a were found 106.6 g P 1^–1, 18.4 g 1^–1, 29.7 g 1^–1 respectively. There is a tendency of the reservoir to decline into a hypertrophic state from a eutrophic one. River Strimon contributes significantly to the overloading of the reservoir by nitrogenous agricultural effluents.