The Rita storm event (September 25-26, 2005) caused the Lorette River to flood the Saint-Jean-Baptiste Street area in Quebec City. Tetra Tech CSO developed the Lorette River Catch Basin Drainage Master Plan, and carried out the design and the implementation of a Real Time Control (RTC) solution for flooding mitigation in this area.
The stormwater master plan recommended various flood protection solutions over the short and long term in order to decrease flood occurrences and hydraulic restrictions in the sewer and storm networks, the Lorette River, and other watercourses in the area for existing and future conditions.
The City of Quebec opted for an RTC solution in order to control flooding conditions for a centennial storm event. The flood protection solution involved the construction of two retention basins (100,000 m³ each) along the two main tributary creeks (Des Friches and Mont-Châtel), and new pumping stations, as well as the control of flap gates and dykes in the downstream sectors of the Lorette River. RTC is the key to this integrated solution, as it not only ensures the effective operation of the flood protection works, but also significantly decreases construction costs by greatly reducing the sizes of the retention basins compared to a static control method.
For the implementation of the RTC flood protection solution, Tetra Tech CSO provided the preliminary and detailed design of the storage basins, the RTC system architecture, and the monitoring stations in urban rivers. They also assisted the City in obtaining environmental certificates and land ownership prior to construction, provided construction supervision, programmed the local controllers and developed the control and monitoring software tools for operation from a central station. Finally, they performed the start-up of control sites and the monitoring of initial system performance.
The RTC system has been in service with a first storage basin since the spring of 2013. A second storage basin will be integrated into this system by 2015.