Modifications required to the City of Montreal's plan to release untreated wastewater into the St. Lawrence River
Backgrounder
Overview
On October 18, 2015, the Minister of the Environment mandated an independent scientific panel to review the City of Montreal’s planned release of eight billion liters of untreated wastewater into the St. Lawrence River.
Following a thorough review of the independent scientific experts’ findings, Environment and Climate Change Canada issued a final Order on November 9, 2015, requiring the City of Montreal to modify its plans and setting four main conditions that must be met.
Conditions of the Final Order
The Government of Canada requires the following modifications to the City of Montreal’s planned release of untreated wastewater. These conditions apply if the discharge associated with the construction proposed by the City occurs between October 1, 2015 and December 5, 2015. Should the construction not take place during this period, conditions for the discharge may have to be re-evaluated by the Minister.
- The City of Montreal must carry out visual surveillance of the effluent plume to identify locations of accumulation. The City of Montreal must deploy, where appropriate, floating booms or other measures where matter has resurfaced and accumulated, and take necessary actions to clean those areas.
- The City of Montreal must prepare and have in place a management plan with respect to unanticipated deposits from large industrial, institutional or commercial facilities to the City of Montreal’s sewers during the construction period.
- The City of Montreal must provide Environment and Climate Change Canada with data and results of water quality, effluent quality, and monitoring of sediments and flora at the points of discharge of untreated effluent as well as selected locations downstream from the project plume, for a period running until June 2016.
- The City of Montreal must participate in a comprehensive review of the events leading to this incident, which will be led by the Department of the Environment and Climate Change, and will include those who may be affected by the release, including neighbouring First Nations communities and the Province. An important objective of this review will be to ensure that proper engagement and consultations take place with respect to similar plans in the future. The review will reflect the objective that such a discharge does not reoccur in the future. It will also reflect our commitment to establishing respectful relationships with First Nations based on mutual recognition, openness, respect, and transparency, and will include timely exchange of information to ensure the full and meaningful participation of all interested parties.
Summary of the Recommendations of the Independent Scientific Report
- Risks associated with an unplanned discharge: The report concluded that these risks are not negligible. The experts could not quantify the risk, but stated that it likely increases exponentially over time. The degradation of the infrastructure could limit the treatment capacity of the treatment plant and also result in unplanned breakage requiring emergency repairs.
- Possible mitigation measures: The experts reviewed the 20 mitigation measures considered by Montreal. They determined that five of the 20 measures would help reduce overflows at the treatment plant but would not help mitigate the release of untreated wastewater resulting from the repair of the sewer. The experts acknowledged that Montreal has retained seven of the remaining 15 measures and suggested that Montreal enhance these measures to some degree. Of the remaining eight measures not retained by Montreal, the experts identified five that could result in a reduction of pollution, but also noted that it would not be realistic to implement some of these during the discharge period currently being considered (Fall 2015).
- Environmental risks in terms of best/worst case scenarios: The report concluded that the best case scenario for a release of untreated wastewater is a planned release where timing is controlled and mitigation measures can be planned and implemented. The worst case scenario is an unplanned release which could result in a larger quantity of untreated wastewater being released, over a longer period of time, because specialized work crews and equipment needed to make the repairs would likely not be immediately available. The timing of an unplanned release could also lead to greater risk to the fish reproductive cycle. The worst case scenario may also result in obstruction of the sewer causing backflow into residential, commercial and industrial facilities. The experts indicated that an unplanned release would result in greater environmental impacts.
- Water quality monitoring requirements: The experts recommended enhancements to the environmental monitoring which could include biological monitoring of fish and bivalves in order to provide essential information for future evaluation of impacts related to discharges of untreated wastewater. Furthermore, they recommended that the monitoring be done over a longer period of time, at least until the indicators return to normal values. They also noted the importance of careful monitoring at drinking water treatment plants over the duration of the project despite the low risk of impact.
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Hon. Catherine McKenna Environment and Climate Change Canada Nature and Environment