Modern methods of monitoring estuarine waters on the example of the Tiligul Estuary

Manual monitoring of the eutrophication status of water bodies such as estuaries is a rather difficult task. Drone technology can be used to assist in monitoring any water body. This study was conducted with the aim of applying remote sensing methods based on unmanned aerial vehicles (UAVs) to obtain eutrophication indicators in the waters of the Tiligul Estuary. The information was based on data collected by drones on the level of eutrophication and the state of marine areas. A DJI Phantom 4 Pro drone was used to collect data from the air. Four sampling points were selected for testing, where the normalised vegetation difference index and normalised turbidity difference index were evaluated. Exsitu data, such as nitrate concentration and phosphate concentration, were also obtained. A trophic status index was calculated to describe the algae content in the estuary. The UAV hyperspectral images were orthorectified and georeferenced in Agisoft PhotoScan software and the normalised difference vegetation index values were evaluated in ArcGIS. The results showed a correlation between the vegetation difference index values and the concentration of nitrogen and phosphorus with coefficients of 0.7079 for phosphorus concentration and 0.7004 for nitrogen concentration, respectively. This study confirmed the applicability of remote sensing for water resource management using UAVs, which is characterised as a fast and simple methodology. A qualitative assessment and control of environmental parameters during the solution of environmental monitoring tasks for marine areas and coastlines was proposed. It was noted that mathematical and simulation modelling methods contribute to the formation of functional and information models, and system analysis methods are also used to identify structural relationships between components of complex systems. The results of the study will enable the further use of UAVs and other remote sensing methods for monitoring and forecasting the state of estuaries and marine areas