Bi Eustache Gooré, Monette Frédéric, Gachon Philippe, Gaspéri Johnny, Perrodin Yves
Department of Construction Engineering, École de Technologie Supérieure, Université du Québec, 1100 Notre-Dame Street West, Montréal, Québec, Canada, H3C 1K3,
Environ Sci Pollut Res Int. 2015 Aug;22(15):11905-21. doi: 10.1007/s11356-015-4411-0. Epub 2015 Apr 14.
Projections from the Canadian Regional Climate Model (CRCM) for the southern part of the province of Québec, 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.
加拿大魁北克省南部地区的加拿大区域气候模型（CRCM）预测表明，到2050年（2041 - 2070年）极端降水事件将会增加。本研究的主要目标是对2013年夏季导致加拿大隆格伊市“罗兰 - 特里安”合流制排水系统溢流的降雨强度增加20%所产生的影响进行定量和定性评估。使用PCSWMM 2013模型评估在当前（2013年）和未来（2050年）气候条件下这种溢流的敏感性。模拟的定量变量（峰值流量、Q(CSO)和排放体积，VD）作为推导生态毒理学风险指数和输送到圣劳伦斯（SL）河的事件通量（EFs）的基础。结果表明，基于5月至10月测量的8次降雨事件，到2050年（与2013年相比）VD增加了15%至500%，Q(CSO)增加了13%至148%。这些结果表明：（i）降水与合流制排水系统溢流变量之间的关系是非线性的；（ii）必须修订当前水利基础设施的设计标准，以考虑降水模式变化引起的气候变化（CC）的影响。由于气候变化导致的大量VD，未来排入圣劳伦斯河的EFs将比现在（2013年）大2.24倍。这反过来又会导致大量总悬浮固体（TSSs）以及多种城市污染物（有机物、营养物、金属）的示踪剂过量输入到受纳水体中。与2013年相比，到2050年生态毒理学风险指数将增加超过100%。鉴于存在大量的VD，并且尽管气候变化情景有许多不确定性来源，但仍必须制定使该排水网络适应气候变化影响的策略。
