Doctoral Dissertation Research: Multi-Spatial Forecasts of Hydrologic Sensitivity to Climatic Change in the Pacific Northwest: A Process-Based Modeling Approach

太平洋西北部的夏季水流为水生生物群、农业、水力发电、娱乐和城市使用提供了水。该地区的水资源已经有限，预计在未来几十年将更加有限。与气候变化相关的较高气温可能会导致积雪和融雪减少，从而减少夏季的流量。由于基岩地质对补给（融雪或雨水）成为径流速率的影响，预测与积雪变化相关的径流敏感性的空间格局变得复杂。在俄勒冈瀑布中，年轻的高喀斯喀特省和古老的西部喀斯喀特省之间明显的水文地质差异是排水速率和最终流量的主要控制因素。在这个博士论文研究项目中，博士候选人将使用基于过程的水文模型（RHESSys）来预测麦肯齐河流域（威拉米特河的主要支流）对气候变化的分布式流量敏感性。现场工作将监测水流，并产生一个框架来分配模型参数。水流预测将与水库模型相结合，以评估麦肯齐流域三个大型水库对潜在气候变化的敏感性。本研究的目的是为了更好地了解积雪控制与地质对俄勒冈瀑布多尺度径流的相互作用及其对气候变化的响应。这项研究的结果将对水资源管理和水库运作具有重要意义，这些水库利用水流进行娱乐、发电、市政供应，并有助于调节水生栖息地。本研究采用的方法，包括明确包含和整合积雪、融雪、地下水排水模式和水库运行，是可以应用于其他系统的建模和气候变化调查的方法，包括那些没有大量河流记录的系统。这项研究补充了正在进行的更大的研究计划，旨在表征气候变化对美国西部山区水资源影响的空间结构。该奖项将支持一名本科生实地助理，作为博士论文研究改进奖，也将支持一名有前途的学生建立强大的独立研究事业

Summer streamflow in the Pacific Northwest provides water for aquatic biota, agriculture, hydroelectric generation, recreation, and urban use. Water resources in the region are already limited and are expected to become more so in coming decades. Higher air temperatures associated with climatic change likely will lead to reduced snow accumulation and snow melt, reducing summer streamflows. Predicting spatial patterns of stream flow sensitivity associated with snowpack change is complicated by the influence of bedrock geology on the rate at which recharge (snowmelt or rain) becomes streamflow. Within the Oregon Cascades, distinct hydrogeologic differences between the younger High Cascade province and the older Western Cascade province are dominant controls on drainage rates and ultimately streamflow. In this doctoral dissertation research project, the doctoral candidate will use a process-based hydrologic model (RHESSys) to predict distributed streamflow sensitivity to climatic change within the McKenzie River basin, a major Willamette River tributary. Fieldwork will monitor streamflow and produce a framework to distribute model parameters. Streamflow predictions will be integrated with reservoir models to assess the sensitivity to potential climatic change for three large reservoirs in the McKenzie watershed. The objective of this study is to provide a better understanding of the interaction among the controls of snowpack and geology on streamflow at multiple scales and its response to climatic change in the Oregon Cascades.The results of this research will have important implications for water resources management and reservoir operations that utilize streamflow for recreation, power generation, municipal supply, and to help regulate aquatic habitat. The methods employed by this research, including the explicit inclusion and integration of snow accumulation, snow melt, groundwater drainage patterns, and reservoir operations, are methods that can be applied to modeling and climatic change inquiry in other systems, including those without substantial streamflow records. This research complements ongoing larger research initiatives designed to characterize the spatial structure of climatic change impacts on water resources within the mountains of the western U.S. This award will support an undergraduate field assistant, and as a Doctoral Dissertation Research Improvement Award, will also provide support to enable a promising student to establish a strong independent research career