Assessment of the Local Impact of Retention Reservoirs—A Case Study of Jagodno (Existing) and Sarny (Planned) Reservoirs Located in Poland

Abstract

The construction of retention reservoirs that cause permanent water damming is a complex subject and requires an interdisciplinary approach to environmental issues. The scope of the conducted study includes (1) a natural inventory of the area of Jagodno Reservoir in central Poland, which has been in operation for almost a decade, (2) a natural inventory of the area where a reservoir of similar size could potentially be built (Sarny, in southwestern Poland), (3) an assessment of the local community’s attitudes toward the operation or construction of individual facilities, (4) analysis and use of the obtained results to predict the local impact of Sarny Reservoir. The results of this study indicate areas where the impact of Jagodno Reservoir should be considered negative, neutral, or positive and what effect can be expected during the construction of Sarny Reservoir. One of the more significant results for Jagodno Reservoir, we should point out, is the appearance of a few waterfowl breeding at the site (4 species), a substantial expansion of the ichthyofauna population (from 9 to 24 species, which does not apply only to native species), a local loss of 91E0 habitat (willow riparian forests) and the appearance of one species of an invasive plant (Canadian goldenrod), a favorable impact on the water quality of the River Wiązownica (reduction in total and nitrate nitrogen loads by an average of 43.4% and 58.2%, respectively), and a positive assessment of the reservoir’s impact on the development of the region by the local community (19 out of 26 village leaders expressed positive opinions with no unambiguously negative votes).