Predicting flood risk is important for climate change adaptation. We quantify fluvial flood risk due to changing climate in a mixed-use watershed in Michigan, USA. We apply two approaches to project future climate change: an ensemble of temperature and precipitation perturbations on the historical record and an ensemble of global and regional climate models. We incorporate climate projections into the Soil and Water Assessment Tool (SWAT) to estimate daily streamflow, then quantify flood risk using indices related to flood probability, duration, magnitude, and frequency. Results indicate rising temperatures may counteract small increases in precipitation, likely due to increased evapotranspiration. Climate model data without bias correction used in SWAT produced reasonable future streamflow changes—similar to the perturbation of historical climate—therefore retaining the predicted change in the flood frequency distribution. This work advances the application of climate models in SWAT for flood risk evaluation at watershed scales.

预测洪水风险对于适应气候变化很重要。在美国密歇根州的一个综合用途流域，我们对由于气候变化而导致的河流洪水风险进行了量化。我们采用两种方法来预测未来的气候变化：对历史记录的温度和降水扰动的综合以及对全球和区域气候模型的综合。我们将气候预测纳入土壤和水评估工具（SWAT）中，以估计每日流量，然后使用与洪水概率，持续时间，强度和频率相关的指数来量化洪水风险。结果表明，升高的温度可能抵消了降水的少量增加，这可能是由于蒸散量增加了。SWAT中使用无偏差校正的气候模型数据产生了合理的未来流量变化，类似于历史气候的扰动，因此保留了洪水频率分布中的预测变化。这项工作促进了SWAT中气候模型在流域尺度上洪水风险评估中的应用。