Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, 2900, boul. Édouard-Montpetit, Montréal, QC H3T 1J4, Canada.
Department of Civil Engineering, Faculty of Engineering, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC J1K 2R1, Canada.
Sci Total Environ. 2015 Mar 1;508:462-76. doi: 10.1016/j.scitotenv.2014.11.059. Epub 2014 Dec 12.
This study presents an analysis of climate change impacts on a large river located in Québec (Canada) used as a drinking water source. Combined sewer overflow (CSO) effluents are the primary source of fecal contamination of the river. An analysis of river flowrates was conducted using historical data and predicted flows from a future climate scenario. A spatio-temporal analysis of water quality trends with regard to fecal contamination was performed and the effects of changing flowrates on the dilution of fecal contaminants were analyzed. Along the river, there was a significant spatial trend for increasing fecal pollution downstream of CSO outfalls. Escherichia coli concentrations (upper 95th percentile) increased linearly from 2002 to 2012 at one drinking water treatment plant intake. Two critical periods in the current climate were identified for the drinking water intakes considering both potential contaminant loads and flowrates: local spring snowmelt that precedes river peak flow and extra-tropical storm events that occur during low flows. Regionally, climate change is expected to increase the intensity of the impacts of hydrological conditions on water quality in the studied basin. Based on climate projections, it is expected that spring snowmelt will occur earlier and extreme spring flowrates will increase and low flows will generally decrease. High and low flows are major factors related to the potential degradation of water quality of the river. However, the observed degradation of water quality over the past 10 years suggests that urban development and population growth may have played a greater role than climate. However, climate change impacts will likely be observed over a longer period. Source water protection plans should consider climate change impacts on the dilution of contaminants in addition to local land uses changes in order to maintain or improve water quality.
本研究分析了位于加拿大魁北克省的一条用于饮用水源的大河受到气候变化的影响。合流制污水溢流 (CSO) 污水是该河受到粪便污染的主要来源。利用历史数据和未来气候情景下的预测流量对河川径流量进行了分析。对水质随粪便污染的时空变化趋势进行了分析，并分析了流量变化对粪便污染物稀释的影响。在河流的下游，靠近 CSO 排放口的地方，粪便污染呈显著的空间趋势。在一个饮用水处理厂的进水口，从 2002 年到 2012 年，大肠杆菌浓度（95%上限）呈线性增加。考虑到潜在的污染物负荷和流量，在当前气候条件下，有两个关键时期对饮用水进水口产生影响：在河川流量达到峰值之前的当地春季融雪期，以及在低流量期间发生的温带风暴事件。从区域上看，气候变化预计会增加水文条件对研究流域水质的影响的强度。根据气候预测，预计春季融雪将提前发生，极端春季流量将增加，而低流量将普遍减少。高流量和低流量是与河流水质潜在退化相关的主要因素。然而，过去 10 年来水质的退化表明，城市发展和人口增长的影响可能比气候更大。然而，气候变化的影响可能需要更长的时间才能显现。水源保护计划应考虑气候变化对污染物稀释的影响，除了考虑当地土地利用变化，以维持或改善水质。
