The existence of McGillivray Falls indicates that this stream is relatively young in terms of geological time, and that this is a primitive drainage system. After many thousands of years, these waterfalls will erode down to a smooth channel. The rock face on the other side of the falls has no water-line or other marks of erosion by the stream. This is because the stream follows a natural channel cut in the rock by the movement of glaciers, which melted away about 12,000 years ago. Had there been no natural depression, the stream would not be flowing here, as the granite rock is very resistant to water erosion.
Beavers bring about changes in drainage by building dams with branches and mud.
The dams create reservoirs in the stream, resulting in lower but more constant flow downstream. For more information on the beaver visit the Picket Creek Trail and the Whiteshell Museum at Nutimik Lake in the north end of the park. From this viewpoint you can see the natural depression in the bedrock. This depression has been partially filled with material carried down by the stream and washed in from all sides. It has taken thousands of years to reach this stage.