Significant Valleylands were identified in the County’s Natural heritage system Study – Green in Grey (January 2017). Detailed delineations of Significant Valleylands should be evaluated on a site specific basis through an environmental impact study using the following criteria:
- The valley must be ≥100 meters wide and ≥2 kilometers long.
- The valley banks must be ≥3 meters in height (extrapolated from 5 meter contours at 1:10,000 or better information where available).
- Where valley slope is 3:1 on one side with no slope on the opposite side of the watercourse, the opposite valley limit is delineated using either 100m from centerline of the watercourse or the limit of the floodplain to create a continuous valley feature.
- Where 3:1 valley slopes occur on both sides of the river, but they are not continuous, the floodplain limit (or contour information and professional judgment) is used to delineate a continuous valley feature