CSO Planning, Design and Implementation of Storage Facilities and a RTC System to Minimize CSOs in Quebec City

In order to meet the environmental objectives for the Jacques-Cartier Beach and St. Charles River and for flooding control in one area, Tetra Tech CSO prepared the CSO Long Term Control Plan (LTCP) for the City of Quebec between 1988 and 1995. The solution called for multiple storage basins to increase capacity at strategic locations and optimal operation of these basins.

Following the success of the pilot implementation of the real time control (RTC) technology, the City of Quebec decided to proceed with the implementation of a centralized RTC system and the construction of 16 storage facilities with capacities ranging from 2,600 m³ (0.7 MG) to 32,000 m³ (8.5 MG), at a total cost of $140 M. One major pumping station was also upgraded to increase capacity from 2 m³/s (46 MGD) to 3 m³/s (68 MGD). The construction phases are summarized as follows:

  • Pilot implementation: Westerly District, RTC for existing tunnels (total capacity 15,000 m³ / 4 MG);
  • Phase 1: Construction of seven basins (total storage volume of 43,700 m³ / 11.5 MG) and extension of RTC in the Easterly District;
  • Phases 2 & 3: Construction of seven basins (total storage volume of 72,000 m³ / 19 MG) and pumping station upgrade;
  • Construction of two basins(total storage volume of 23,000 m³ / 6.1 MG), one for flooding protection use.

Activities carried out by Tetra Tech CSO during this project included:

  • Preparation of the CSO LTCP and preliminary engineering in all disciplines;
  • Definition of RTC management strategies;
  • Technical management of the detailed engineering phase for ten consultants;
  • Detailed engineering for all instrumentation and control works;
  • Design of the central station and telecommunications;
  • SCADA system integration, programming and start-up;
  • Performance tests versus the objectives (equipment and environmental);
  • Design of a secured access Web application to monitor rain, flow and level data in real-time and to consult archived data;
  • Training and technology transfer;
  • Technical support and assistance.


“In addition to reducing the occurrence of CSOs by 60% and the volume of contaminated water by 50%, RTC has also allowed over $90 million in savings in equipment that had been foreseen during the initial planning of this project. The Communautéurbaine de Québec has just completed its second year of operation with the new RTC CSO system and is very satisfied with the results.”

Serge Allen, General Manager of Communauté urbaine de Québec


Key Contact

Diana Tao

Director of Business Development
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