Considerable efforts are underway to restore watersheds and estuaries downstream impacted by urban development; however, climate change (CC) may be undermining them. Current methods are limited in their ability to predict hydrology and water quality with CC and assess its effect on the efficiency of stormwater control measures (SCMs). We developed a method using downscaled global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to project precipitation and temperatures; these were used to force a Storm Water Management Model (SWMM). Three scenarios, a historical and two Representative Concentration Pathways (RCP 4.5 and 8.5) with five GCMs, were used to produce ensemble results. All GCMs in both RCP scenarios projected increases in precipitation and temperature compared to historical conditions. Both RCPs exhibited their largest increases in precipitation, streamflow, total suspended solids (TSS), total nitrogen (TN), and total phosphorous (TP) loads in the winter, summer exhibited the largest increase in temperature. Median loads of TSS, TN, and TP increased 3.1%, 2.5%, and 9.9%, respectively, for RCP 4.5, and increased 3.8%, 3.1%, and 10.4%, respectively, for RCP 8.5. Median reductions in TSS, TN, and TP SCM efficiency for RCP 4.5 were projected to be 6%, 7%, and 11%, respectively; and 11%, 12%, and 17% for RCP 8.5, respectively. Thus, it is likely that additional efforts will be needed to meet water quality goals in the future. Methods such as these can help create climate resilient watershed improvement strategies and guide urban stormwater planning against likely future changes as a result of CC.

中文翻译：

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使用集成方法评估气候变化对城市流域水质和水量的影响

为恢复受城市发展影响的下游流域和河口，正在作出巨大努力；但是，气候变化（CC）可能正在破坏它们。当前的方法利用CC预测水文和水质以及评估其对雨水控制措施（SCM）效率的能力有限。我们使用耦合模型比较项目第5阶段（CMIP5）的降尺度全球气候模型（GCM）开发了一种方法来预测降水和温度。这些用于强制实施雨水管理模型（SWMM）。三种情景，即具有五个GCM的历史情景和两个代表性浓度路径（RCP 4.5和8.5）被用来产生整体结果。与历史情况相比，在两种RCP方案中，所有GCM均预计降水量和温度会增加。在冬季，两个RCP在降水，流量，总悬浮固体（TSS），总氮（TN）和总磷（TP）的负荷方面表现出最大的增幅，而夏季的温度增幅最大。对于RCP 4.5，TSS，TN和TP的中值负载分别增加了3.1％，2.5％和9.9％，对于RCP 8.5，中值负载分别增加了3.8％，3.1％和10.4％。预计RCP 4.5的TSS，TN和TP SCM效率降低的中位数分别为6％，7％和11％。对于RCP 8.5分别为11％，12％和17％。因此，将来可能需要付出更多的努力才能达到水质目标。诸如此类的方法可以帮助制定应对气候变化的流域改善策略，并指导城市雨水规划以应对由于CC造成的未来可能的变化。