Projections from the Canadian Regional Climate Model (CRCM) for the southern part of the province of Quebec, Canada, suggest an increase in extreme precipitation events for the 2050 horizon (2041-2070). The main goal of this study consisted in a quantitative and qualitative assessment of the impact of the 20 % increase in rainfall intensity that led, in the summer of 2013, to overflows in the Rolland-Therrien combined sewer system in the city of Longueuil, Canada. The PCSWMM 2013 model was used to assess the sensitivity of this overflow under current (2013) and future (2050) climate conditions. The simulated quantitative variables (peak flow, Q(CSO), and volume discharged, VD) served as the basis for deriving ecotoxicological risk indices and event fluxes (EFs) transported to the St. Lawrence (SL) River. Results highlighted 15 to 500 % increases in VD and 13 to 148 % increases in Q(CSO) by 2050 (compared to 2013), based on eight rainfall events measured from May to October. These results show that (i) the relationships between precipitation and combined sewer overflow variables are not linear and (ii) the design criteria for current hydraulic infrastructure must be revised to account for the impact of climate change (CC) arising from changes in precipitation regimes. EFs discharged into the SL River will be 2.24 times larger in the future than they are now (2013) due to large VDs resulting from CC. This will, in turn, lead to excessive inputs of total suspended solids (TSSs) and tracers for numerous urban pollutants (organic matter and nutrients, metals) into the receiving water body. Ecotoxicological risk indices will increase by more than 100 % by 2050 compared to 2013. Given that substantial VDs are at play, and although CC scenarios have many sources of uncertainty, strategies to adapt this drainage network to the effects of CC will have to be developed.
- Climate change (CC) impact study
- Combined sewer overflows (CSOs)
- Hydrological modeling
- PRECIPITATION EXTREMES
- INTENSE PRECIPITATION
- MODEL SIMULATIONS
- MONTREAL AREA
- WET WEATHER
- IDF CURVES
[Bi, Eustache Goore; Monette, Frederic] Univ Quebec, Ecole Technol Super, Dept Construct Engn, Montreal, PQ H3C 1K3, Canada; [Bi, Eustache Goore] City Longueuil, Dept Civil Engn, Longueuil, PQ J3Y 9G4, Canada; [Gachon, Philippe] Univ Quebec Montreal UQAM, Ctr Etud & Simulat Climat Echelle Reg ESCER, Montreal, PQ, Canada; [Gasperi, Johnny] Univ Paris Est, AgroParisTech, LEESU, UMR MA 102, F-94010 Creteil, France; [Perrodin, Yves] Univ Lyon, ENTPE, Lab LEHNA UMR CNRS 5023, Vaulx En Velin, France
Bi, EG (reprint author), Univ Quebec, Ecole Technol Super, Dept Construct Engn, 1100 Notre Dame St West, Montreal, PQ H3C 1K3, Canada.