Located at the western end of Cootes Paradise Marsh, this 44ha floodplain encapsulates the southern side of one of the largest river mouth deltas on Lake Ontario and is a designated Special Protection Area. Its length is 2.5km with an area of approximately 100ha. The delta is fragmented by an old rail line, two roads and the Desjardins Canal.

The delta has two key components: the Spencer Creek floodplain along the south side of the river mouth of Spencer Creek and a band of old growth Carolinian forest stretching inland 100m on the adjacent ravine slope. The floodplain is the most recent natural river delta of Spencer Creek prior to ditching and relocation into the Desjardins Canal in the 1870s.