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Missisquoi Bay Watershed - Evaluation of Wastewater Treatment Systems

Missisquoi Bay watershed – Evaluation of wastewater treatment systems

Better understand how wastewater affects water quality in the Missisquoi Bay watershed

In order to support Missisquoi Bay Watershed Organization (OBVBM) In updating its Water Master Plan, Fondation Rivières carried out a performance evaluation of municipal wastewater treatment systems in this watershed. The objectives: identify sanitation issues between 2014 and 2018 and produce a summary report intended for municipal decision-makers, interest groups and the public. Support was also provided to target intervention sites for a green infrastructure implementation project.

Source : OBVBM

Carte OBVM plan directeur de l'eau

Study area for municipal wastewater treatment works in the Missisquoi Bay watershed. Photo taken from the water master plan (PDE), 2015


Progress report

  • Data compilation Monitoring system for municipal water sanitation works (SOMAE)
  • Interpretation of diagrams and tracking data


Diagnosis and action plan

  • Telephone interviews with many water sanitation services
  • Production of a summary table of suggested courses of action


Partners and collaborators

  • Missisquoi Bay Watershed Organization (OBVBM)
  • Potton
  • sutton
  • Frelighbur
  • Stanbridge East
  • Bedford
  • Our Lady of Stanbridge
  • Venice-in-Quebec
  • St. Armand (Philipsburg)
  • Eastman
  • Abercorn



Treatment plants
Overflow structures

The raw data from Monitoring of municipal wastewater treatment works (SOMAEU) 2017-2019 were obtained from the Ministry of the Environment (MELCCFP). Of the 11 stations present in the study area, the operators of nine of them participated in a telephone interview (82 % participation). The 3 study areas correspond to the sub-watersheds of the Brochets and Missisquoi rivers as well as that of Missisquoi Bay. The performance diagnosis is divided into two main sections: the performance of the wastewater treatment plants and the performance of the networks and overflow structures.

Duration of the study

The evaluation of wastewater treatment systems was carried out in two phases:

  • Phase 1 – Evaluation of the period 2014-2016: the project ran from August 2018 to January 2019.
  • Phase 2 – Review of the recommendations of phase 1 and evaluation of the 2016-2018 period: the project ran from March 2019 to April 2020.



Nearly half of the stations studied present worrying wastewater treatment performances.


Four of the 11 networks studied need to improve their performance, in particular through better stormwater management.


There was a marked decrease (30 %) in phosphorus loads released into the watershed between 2016 and 2018.

Investments are necessary to maintain water quality in the Missisquoi Bay watershed. They must be granted according to a logic of prioritization on the scale of the entire watershed.

Our mandates for evaluating wastewater treatment systems

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