Regulated Apparent Valleyland

Last data update: February 18, 2019 Riverine Erosion Hazards due to stream bank erosion and slope stability. Hazard areas contain a 15 m setback. This layer is one of the 5 components which comprise Ontario Regulation 41/24. The extent of the slope erosion hazard for confined riverine systems is determined by the stable toe of slope and the stable top of bank. Generally slopes steeper than 8% which are adjacent to other hazards, such as flood plain, wetland and meanderbelt are included in this layer. The toe of slope or stable toe of slope must be located within one of the above hazards. The stable toe of slope is considered to be a minimum distance of 15m from the full bank width of a watercourse. Where the existing toe of slope is greater than 15m from the full bank width of a watercourse, the existing toe is considered stable. Where this distance is less than 15m, the 15 m allowance is used to predict the future location of the stable toe of slope. The stable slope allowance is based on an assumed stable slope gradient of 3 horizontal units to 1 vertical unit. This measurement is taken from the stable toe of slope and projected to a point of intersection with the ground. This intersection point is considered to be stable top of bank. Where the existing slope is flatter than 3 horizontal units to 1 vertical unit the existing top of bank is considered stable. A 15 m setback is applied from the stable top of bank. In 2019 the extent was updated to LSRCA Scientific Watershed boundary.