The continued growth of Southwestern cities depends on reliable water export from Rocky Mountain headwaters, which provide ∼85% of Colorado River Basin (CRB) streamflow. Despite being more sensitive to warming temperatures, alpine systems are simplified in the regional-scale models currently in use to plan for future water supply. We used an integrated hydrologic model that couples groundwater and surface water with snow and vegetation processes to examine the effect of topographic simplifications as a result of grid coarsening in a representative CRB headwater basin. High-resolution (100 m) simulations predicted headwater streamflow losses of 16% by 2050 while coarse-resolution (1 km) simulations predict only 12%, suggesting that regional-scale models (coarser than 1 km) likely overestimate future Colorado River Basin water supplies.

中文翻译：

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在对科罗拉多河上游水源的气候变化进行建模时，分辨率至关重要

西南城市的持续增长取决于落基山源头可靠的水出口，这些源头提供了约85％的科罗拉多河流域（CRB）流量。尽管对变暖的温度更加敏感，但目前用于计划未来水供应的区域规模模型简化了高山系统。我们使用了一个综合的水文模型，将地下水和地表水与积雪和植被过程结合在一起，以检查代表性CRB上游水域网格粗化导致地形简化的影响。高分辨率（100 m）模拟预测到2050年上游水流损失为16％，而粗分辨率（1 km）模拟预测仅为12％，这表明区域尺度模型（粗于1 km）可能高估了未来的科罗拉多河盆地水耗材。