Utilization of Unmanned Aerial Vehicles (UAVs) for Mapping the Distribution of Water Hyacinth and Evaluating Water Quality Dynamics in Lake Tondano

Lake Tondano, a vital water resource and cultural icon in North Sulawesi, Indonesia, is under increasing ecological stress. This study addresses the dual threat of uncontrolled proliferation of water hyacinth (Eichhornia crassipes) and a concerning decline in water quality. The extensive surface coverage by water hyacinth disrupts the aquatic ecosystem by blocking sunlight, lowering dissolved oxygen (DO), and impairing the lake's aesthetic and economic functions. This research utilized Unmanned Aerial Vehicle (UAV) technology to provide an efficient, high-resolution solution for rapidly mapping the spatial distribution and estimating the extent of the water hyacinth infestation. High-resolution RGB aerial imagery was collected, and water quality was simultaneously assessed through laboratory analysis of samples taken from both infested and clear areas. The mapping results identified a significant 1,034-hectare water hyacinth cover in the Paleloan Village area of the lake. Crucially, the study established a stark water quality dichotomy: areas free of water hyacinth maintained relatively good conditions, largely meeting Class II water quality standards (Government Regulation No. 22 of 2021). In sharp contrast, areas under water hyacinth cover showed severe degradation, evidenced by extremely poor readings for critical parameters, including high Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS), alongside dangerously low Dissolved Oxygen (DO). This research provides compelling evidence of a strong negative correlation between the presence of E. crassipes and the deterioration of essential water quality parameters, advocating for urgent and targeted management interventions informed by remote sensing data.