Changing climate and land cover are expected to impact flood hydrology in the Delaware River Basin over the 21st Century. HEC‐HMS models (U.S. Army Corps of Engineers Hydrologic Engineering Center‐Hydrologic Modeling System) were developed for five case study watersheds selected to represent a range of scale, soil types, climate, and land cover. Model results indicate that climate change alone could affect peak flood discharges by −6% to +58% a wide range that reflects regional variation in projected rainfall and snowmelt and local watershed conditions. Land cover changes could increase peak flood discharges up to 10% in four of the five watersheds. In those watersheds, the combination of climate and land cover change increase modeled peak flood discharges by up to 66% and runoff volumes by up to 44%. Precipitation projections are a key source of uncertainty, but there is a high likelihood of greater precipitation falling on a more urbanized landscape that produces larger floods. The influence of climate and land cover changes on flood hydrology for the modeled watersheds varies according to future time period, climate scenario, watershed land cover and soil conditions, and flood frequency. The impacts of climate change alone are typically greater than land cover change but there is substantial geographic variation, with urbanization the greater influence on some small, developing watersheds.

中文翻译：

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气候变化和土地覆盖变化对美国特拉华河流域洪水强度的影响

预计气候变化和土地覆盖将影响21世纪特拉华河盆地的洪水水文学。HEC-HMS模型（美国陆军工程兵团水文工程中心-水文建模系统）是针对五个案例研究流域开发的，这些分水岭代表了规模，土壤类型，气候和土地覆盖范围。模型结果表明，仅气候变化可能会在最大范围内影响洪峰流量的−6％至+ 58％，这反映了预计的降雨，融雪和局部集水区条件的区域差异。土地覆盖的变化可能会使五个流域中的四个流域的洪峰流量增加多达10％。在这些流域中，气候变化和土地覆盖变化共同使模拟洪峰流量最多增加66％，径流量最多增加44％。降水预测是不确定性的一个主要来源，但是很有可能更大的降雨落在城市化的景观上，从而引发更大的洪水。模拟流域的气候和土地覆盖变化对洪水水文的影响随未来时间段，气候情景，流域土地覆盖和土壤状况以及洪水频率而变化。通常，仅气候变化的影响就大于土地覆盖的变化，但地理差异却很大，而城市化对一些小的发展中流域的影响更大。模拟流域的气候和土地覆盖变化对洪水水文的影响随未来时间段，气候情景，流域土地覆盖和土壤状况以及洪水频率而变化。通常，仅气候变化的影响就大于土地覆盖的变化，但地理差异却很大，而城市化对一些小的发展中流域的影响更大。模拟流域的气候和土地覆盖变化对洪水水文的影响随未来时间段，气候情景，流域土地覆盖和土壤状况以及洪水频率而变化。通常，仅气候变化的影响就大于土地覆盖的变化，但地理差异却很大，而城市化对一些小的发展中流域的影响更大。