Monitoring of indicators of water quality, eutrophication and the tufa-building process – is conducted by the staff of the Service for the protection, maintenance, conservation, promotion and use of Plitvice Lakes National Park. Monitoring has been performed monthly at some 20 stations continuously since 2006, based on the recommendations of scientific research.
Monitoring hydrological indicators – continuous hydrological monitoring began in 1951, with the installation of hydrological stations. Today there are 14 such stations in the park, and they continuously monitor water levels and water flow, and the data are collected and processed by the State Hydrological and Meteorological Institute. On certain watercourses, water flow and flow rates are measured independently by the staff of the Service for the Protection, Maintenance, Conservation, Promotion and Use of Plitvice Lakes National Park.
National water quality monitoring – Croatian Waters (Central Water Management Laboratory) conduct surveillance monitoring on four monitoring sites of surface waters and three monitoring sites of groundwaters in the area of NP Plitvice Lakes. According to the criteria defined in the Regulation on water quality standards (OG 73/13, 151/14, 78/15 & 61/16) the ecological and chemical status of the surface water body and the chemical and quantitative status of the groundwater body, are assessed. Monitoring of surface waters is carried out once a month at the stations of Prošćansko lake, Kozjak lake, Crna Rijeka river and Korana river, while the monitoring of groundwater is carried out four times a year at the stations of the source of Crna Rijeka, source of the Plitvica and source Vrelo Koreničko.