Changes in hydrological, physical and chemical properties of water in closed/open coastal lakes due to hydrotechnical structures

The purpose of the study was to determine quantitative and qualitative changes in the waters of Lake Jamno in northern Poland due to the presence of new hydrotechnical structures in its drainage basin, with a special focus on the effects of a new storm barrier. The study consisted primarily of a review of measurement data, historical records and fieldwork prior to the construction (2002–2008) and following the construction of the storm barrier (2015). Fieldwork included hydrographic surveys and water sampling for laboratory analysis. The main and most easily discernible effect of the construction is the change in water quality in Lake Jamno. This is particularly true in the case of key indicators related to seawater, including conductivity, whose values changed from brackish to fresh water.