Johnson T, Butcher J, Deb D, Faizullabhoy M, Hummel P, Kittle J, McGinnis S, Mearns L O, Nover D, Parker A, Sarkar S, Srinivasan R, Tuppad P, Warren M, Weaver C, Witt J
Office of Research and Development, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. NW, MC8601P, Washington, D.C. 20460.
Tetra Tech, Inc., Research Triangle Park, North Carolina 27709.
J Am Water Resour Assoc. 2015 Oct 1;51(5):1321-1341. doi: 10.1111/1752-1688.12308.
Watershed modeling in 20 large, United States (U.S.) watersheds addresses gaps in our knowledge of streamflow, nutrient (nitrogen and phosphorus), and sediment loading sensitivity to mid-21st Century climate change and urban/residential development scenarios. Use of a consistent methodology facilitates regional scale comparisons across the study watersheds. Simulations use the Soil and Water Assessment Tool. Climate change scenarios are from the North American Regional Climate Change Assessment Program dynamically downscaled climate model output. Urban and residential development scenarios are from U.S. Environmental Protection Agency's Integrated Climate and Land Use Scenarios project. Simulations provide a plausible set of streamflow and water quality responses to mid-21st Century climate change across the U.S. Simulated changes show a general pattern of decreasing streamflow volume in the central Rockies and Southwest, and increases on the East Coast and Northern Plains. Changes in pollutant loads follow a similar pattern but with increased variability. Ensemble mean results suggest that by the mid-21st Century, statistically significant changes in streamflow and total suspended solids loads (relative to baseline conditions) are possible in roughly 30-40% of study watersheds. These proportions increase to around 60% for total phosphorus and total nitrogen loads. Projected urban/residential development, and watershed responses to development, are small at the large spatial scale of modeling in this study.
对美国20个大型流域进行的流域建模，填补了我们在了解21世纪中叶气候变化以及城市/住宅开发情景下，河流流量、养分（氮和磷）和沉积物负荷敏感性方面的知识空白。采用一致的方法有助于在各研究流域之间进行区域尺度的比较。模拟使用土壤和水资源评估工具。气候变化情景来自北美区域气候变化评估计划动态降尺度的气候模型输出。城市和住宅开发情景来自美国环境保护局的综合气候与土地利用情景项目。模拟提供了一套合理的、关于美国21世纪中叶气候变化下河流流量和水质响应的情况。模拟变化显示出一种总体模式：落基山脉中部和西南部的河流流量减少，而东海岸和北部平原的流量增加。污染物负荷的变化遵循类似模式，但变异性增加。集合平均结果表明，到21世纪中叶，大约30%-40%的研究流域的河流流量和总悬浮固体负荷（相对于基线条件）可能会出现具有统计学意义的变化。对于总磷和总氮负荷，这些比例增加到约60%。在本研究的大空间尺度建模中，预计的城市/住宅开发以及流域对开发的响应较小。
