Back Brook Dam Removal

Back Brook dam (1930)
Back Brook, Dorchester, New Brunswick (slideshow, aerial photo)

Dimensions of structure: 3.2 metres high by 25.8 metres long
Drainage area: Approximately 5 km2

The Back Brook dam removal project was the first project of this type to be intitiated in the Petitcodiac Watershed. Dam removal was carried out in August 2002 by Public Works and Government Services Canada and funded by Correctional Services Canada.

This small dam was located on Back Brook, a small tributary of the Memramcook River, in a rural area near the Village of Dorchester. Built in 1930, the dam’s purpose was to create a potable water reservoir for the Federal Penitentiary at Dorchester. However, massive sediment build-up over the years in the headpond rendered the reservoir useless. In fact, the volume of sediment was such that it completely infilled the pond in the area adjacent to the dam, reaching to the top of the structure.

The decision to have the dam removed came as a result of various elements. First, the structure had become obsolete with the reservoir not serving its purpose anymore. Second, the dam had no built-in fishway which meant that fish passage upstream of the structure was impossible. Although the dam could have been left in place as it was still in relatively good condition, building a fishway (the existing configuration of the dam, if not altered, would have been considered a contravention of the Fisheries Act) and future maintenance would have proved as expensive as removing the dam. And third, environmental concerns expressed by local environmental groups such as the Fort Folly First Nations who had had been carrying-out restoration work on Back Brook for some time and also the Petitcodiac Riverkeeper acted as a trigger for the decision to have this small dam removed.

The dam removal work described in this section was documented by the Petitcodiac Riverkeeper in August 2002.

Click here for an excerpt of the inspector’s report for an overview of the removal process on site.

Documents

The draft copy* of the environmental screening (26 p.) prepared by Public Works and Government Services Canada (PWGSC) gives an overview of the dam’s surroundings, potential impacts of the removal and proposed deconstruction and restoration methods. (pdf)

A draft copy* of the plan showing sections of the dam and prepared by PWGSC can be downloaded here (pdf)

A draft copy* of the brook realignment plan can be downloaded here (pdf)

[* While every effort has been made to ensure that the information contained in the report is accurate and factual and that all numerical values are correct, Public Works and Government Services Canada (PWGSC) makes no guarantee to that effect and assumes no liability whatsoever with respect to the use of, or reliance on, any information contained in these documents]