Hydromapping Tool Creation for Sprat Lake Using Unmanned Aerial Vehicles (UAV) Surface From Motion Analysis; A Proactive Approach to Reduce Potential Mercury Fluxes Following Forest Harvesting By Using Variable Retention Buffers and Preplanned Machine Travel Corridors

Abstract

There has been an increase in the awareness and concern regarding mercury contamination in Northwestern Ontario fish. Wetland and low laying areas are considered hotspots for methylmercury production which, when disturbed by harvesting and site preparation equipment, can cause mercury to runoff into the aquatic system and bioaccumulate through the food chain. In this study, a hydromapping tool for Sprat Lake was created through surface from motion analysis of Unmanned Areal Vehicle (UAV) images. This tool determined areas of high water accumulation on the landscape that might otherwise go undetected. Variable retention buffers were also created with this tool as riparian zones may extend farther than fixed with buffers currently prescribed by Ontario forest management guidelines. Wetland environments were identified and classified to ensure that they could be avoided by heavy equipment during harvesting and tending treatments. Road corridors were also outlined to steer heavy equipment away from low laying areas. This proactive approach reduces surprises incurred when conducting harvesting and renewal operations and may reduce soil disturbance on sensitive areas, possibly helping to mitigate total mercury and methylmercury fluxes that may sometimes follow forest harvesting disturbance.