The Spencer Creek is a large creek system located mostly within the limits of the city of Hamilton, Ontario. It consists of many fi ngers, some initiating in urban lands, other fl owing through agricultural areas and others falling over natural waterfalls that make up the ecologically, recreationally and culturally important Niagara Escarpment. There are also marshlands and swamps that provide important ecosystem functions within the watershed area and have been subject to many past and present threats. The historical development of the Spencer and the areas surrounding it began with the fi rst appearance of the European settlers in the late 1600’s. This development has led to a decreased level of natural health for the watershed which is certainly not uncommon to most rivers subjected to this level of human intervention: decreased water storage capacity, increased erosion, decreased fi sh and wildlife habitat, reduced overall eco-systemic health and resilience by canalizing and in-fi lling of wetland and marsh areas, etc. As a result of this type of degradation of stream resources on both sides of the Great Lakes (as well as high industrial and urban pollution) the national governments from both the American and Canadian governments signed the Great Lakes Water Quality Agreement (1978). In 1986, 43 Areas of Concern (AOCs) were established that had been particularly degraded and would receive extra attention for clean up. The Hamilton Harbour, which is the eventual outlet for the water of the Spencer Creek, was designated as one these AOCs and as such, the waters and the lands surrounding it have been subject to special attention since this time. Increasingly stringent regulation on water quality in terms of industrial effl uent, increased sewage treatment capacity, increased prevention activities against Alien Invasive Species, have signifi cantly reduced the daily impact on the watershed health and the Harbour has seen great improvements in overall water quality. Great attention is given in the agreement to the need for an eco-systemic approach in the basin. It is expressed through the goals statement:
“to restore and maintain the chemical, physical and biological integrity of the waters of the Great Lakes Basin Ecosystem” (Canada and US 1978: Art. II).