31m 4s: longueur
1120Nombre de vues
1Évaluation

This GRCA webinar [recording] highlights how advanced GIS technologies and the development of a high resolution digital elevation model (DEM) were used to characterize potential nutrient source areas in a pilot study subwatershed. This project demonstrated that the integration of large scale 3D vector hydrology into a high resolution DEM provided an accurate method for routing surface hydrology flow through a watershed drainage area. The creation of DEM-derived models including slope, flow direction and flow accumulation provided a means for evaluating and prioritizing drainage characteristics and highlighted, with a high degree of accuracy, where there was a high probability of gully erosion. Additionally, sheet erosion potential was also characterized using the Revised Universal Soil Loss Equation for application in Canada and overlaid onto those areas with high gully erosion potential, effectively illustrating those areas in the watershed which had a high potential for gully and sheet erosion. Map products were generated at the watershed, subwatershed, farm and field scale through consultation with Conservation Services staff to ensure map products would be effective in starting the discussion about erosion and nutrient loss with local farmers in the area. These critical source area maps were catalysts for engaging local farmers and resulted in the initiation of an on-farm soil erosion project. A goal of the Water Management Plan for the Grand River watershed is to improve river health. Long standing water quality issues in the Grand River watershed are high nutrient and sediment concentrations from rural/agricultural nonpoint sources. To achieve the goal of improved river health, GRCA, OMAF, and MOE staff worked together to develop an approach to map 'critical source areas' in priority subwatersheds.