In Canada, one of the major challenges associated with infrastructure development has been the need to
maintain a balance between planned urban growth and expansion of services without compromising the
commitment to protection of significant environmental features. With technologically advanced construction
techniques, ecologically sustainable solutions with minimal impacts to environmental features are now more
feasible economically and technically. For example, the Devil’s Creek trunk sewer project was a sewer
construction project that gradually evolved into a major ecological enhancement and restoration endeavour that persisted despite seemingly insurmountable constraints. The Devil’s Creek project is the first Canadian
microtunnelling application and sewer construction project to cross a provincially protected significant wetland and a regional environmentally sensitive area with full approval from all levels of government.
The Devil’s Creek Valley is composed of a wetland and adjacent mature growth forest that is well-recognized
for its size, quality, and rare species it supports. Its many significant features include a natural cold-water trout fishery and provincially significant plants and wildlife. Despite the need to protect the valley’s natural features and functions, planning studies conducted as early as the 1970s indicated a need for sanitary sewer servicing to accommodate growth at Cambridge’s west end. The most attractive alternative available in terms of minimizing cost, maintenance, and social disruption was a gravity sewer line along the natural valley system, with a potentially significant impact to the environment.
This paper presents the restoration measures used to reduce the level of impact from gravity sewer construction through 1.3 km of construction easement. A combination of restoration techniques and the results of two years of post-construction monitoring are presented to provide insight on the application of restoration measures for similar projects.