The effect of a water dam on Lake Powidzkie and its vicinity

Abstract

Abstract The paper presents an attempt to assess the effect of damming of lakes on water resources, based on the example of Lake Powidzkie (Central Poland) and its catchment. The region in which the analysed object is located has the greatest water deficits in Poland. The co-occurrence of unfavourable natural and anthropogenic factors contributed to a considerable reduction in the water resources retained in the lake. Particularly low water levels were recorded in the 1990s and in the first decade of the 21st century. The situation was not improved by a water dam constructed on the out-flow from the lake in the 1960s, due, among other things, to neglect in its exploitation. With regard to the modernisation of the dam in 2010 and the favourable hydrological situation in the winter of 2011, it was possible to retain the excess water and substantially reduce its outflow. The restoration of the lost water resources, and the hydrological benefits of this were still observable several years later. Problems related to water deficits are becoming increasingly common in many regions of the world. One solution to mitigate such a situation may be, among others, to dam natural lakes. This is simpler, cheaper, and less invasive for the environment than the construction of new water reservoirs.