Tetra Tech CSO has been developing SWMM models of the wastewater collection network in the territory of the City of Quebec (formerly consisting of 13 separate municipalities) since 1989. At the end of 2003, Tetra Tech CSO was commissioned to develop the Wastewater Collection Network Master Plan
To develop the wastewater master plan in order to evaluate both the existing and ultimate urban development conditions, Tetra Tech CSO carried out the following activities:
- Conducting an inventory of the structural and operational data of the networks and overflow structures;
- Accounting and mapping the claims recorded by the City of Quebec regarding sewer back-ups;
- Updating the sanitary flows for 2003, and for ultimate development conditions;
- Conversion of SWMM models to XPSWMM and model updates;
- Assessing the level of service of all the modeled pipes in actual and ultimate development conditions (based on a rainfall event with a 10-year return period);
- Assessing the performance levels of the modeled overflow structures versus effluent discharge requirements in actual and ultimate development conditions (based on a design rainfall event to satisfy environmental requirements);
- Producing a georeferenced graphic file and reference database;
- Coordinating efforts to determine solutions over the short and long term, including both construction work and structure monitoring with regard to effluent discharge requirements;
- Producing work cost estimates and schedules, as well as prioritizing the interventions.
Since the delivery of the master plan, Tetra Tech CSO has carried out various studies for different sectors, which have increased the level of accuracy of the model and kept the model up to date. Thus, the City can use this tool to make informed and optimal decisions regarding the urban development of the territory and/or the replacement and maintenance of the drainage infrastructures.