The main objective for this component of the study was to improve the extent and locational accuracy of 1st and 2nd order watercourses, which are often difficult to locate and map when working at a large scale such as the Muskoka River Watershed. The DTM used was 50cm bare-earth terrain derived from a classified lidar point cloud, which provided a much higher resolution picture of the study area’s topography than previously available. To ensure the watercourse modelling was as detailed as possible the DTM was not resampled and was kept at the original 50cm resolution. Flow Direction was determined first using the D8 algorithm, followed by flow accumulation. A flow accumulation cut-off of 175000 pixels was used after careful comparison with known watercourses. Watercourses were the extracted from the flow accumulation raster, simplified and connected across the watershed.

The flow direction has been set to match the start/end geometry of the line. Flow direction has also been set for the geometric network using the source/sinks option. Flow direction can be viewed by selecting the "display arrows" button on the Utility Network Analyst toolbar in ArcMap.