The Department of National Defence (DND) is implementing an aquatic contaminated site remediation program in Esquimalt Harbour, as part of a long-term strategy to address sediments that have been contaminated by historical industrial activities in the harbour dating back to the mid-1800s. The project area is currently under the ownership and management of DND and part of the Canadian Forces Base (CFB) Esquimalt. This remediation program is one of the largest being undertaken on the West Coast of Canada, and is being implemented in a phased approach that is initially targeting six areas of higher contaminant concentrations, and for some of the targeted areas coincides with facility upgrades. Longer-term remediation and management of other areas of the harbour will be based on the results of ongoing updates to a human health and ecological risk assessment. Overall, the remediation program is intended to result in a net environment benefit.

Despite the presence of contaminants, the area supports significant environmental resources and the permitting for the remediation project and associated infrastructure upgrades has had to address the habitat protection provisions of the federal Fisheries Act, which has in recent years shifted from an emphasis on productive capacity to productivity. To date, the focus of the Fisheries Act permitting has been for changes to fish habitat related to the facility upgrades rather than for the remediation dredging. 

The shoreline and nearshore areas around Esquimalt Harbour are mostly comprised of hard substrates such as boulders and bedrock, and the seafloor is mostly finer-grained unconsolidated sediments. This substrate gradation determines the habitat values that need to be considered in each remediation zone in terms of quantifying the potential for lost productivity as a result of remediation activities. In the harbour, harder substrates tend to support higher value habitat such as kelp beds and other macroalgae, which are important for species related commercial, recreational and Aboriginal fisheries, as well as protected species such as Northern Abalone (Haliotis kamtschatkana). In addition to being of higher value, these types of habitat also tend to take longer to re-establish once disrupted. Conversely, the softer substrates provide lower habitat value and will recolonize relatively rapidly following dredging. Changes to higher value habitat that takes longer to re-establish has a greater potential to affect productivity and thus a greater potential to result in serious harm to fish as defined by the Fisheries Act and thus a need to provide offsetting to replace the lost productivity.

To support the long-term program of remediation and facility upgrades in Esquimalt Harbour, DND has proactively established a habitat offsetting program that includes a “bank” of fish habitat constructed in advance of activities that might result in serious harm to fish. As each project component is addressed, the productivity loss is quantified and compared to the “credit” available in the bank. In some cases, the type of habitat being affected is different than the habitat in the bank and therefore different “currency conversions” have been applied.

This presentation will discuss how the habitat values in Esquimalt Harbour were characterized, efforts made to avoid disruption of high value habitat, mitigation measures that could be applied to minimize changes to fish habitat, and finally, how these factors were brought together in an overall conclusion of whether serious harm to fish would result from remediation activities and facility upgrades and ultimately whether offsetting was needed.