Understanding and predicting streamflow permanence in response to increasing aridity is the essential first step to mitigating ecological drought and subsequent management of systems that will be resilient in the face of climate change. The objective of this project is to substantially improve the ability of land managers to identify ecologically important headwater streams resilient to drought conditions, enabling them to focus their limited rehabilitation and conservation resources on watersheds necessary to support populations of threatened aquatic species. The understanding and available measurements of water availability in the headwaters at a landscape extent in the Northwest United States is surprisingly incomplete. Analysis of the National Hydrography Dataset (NHD), a primary source for mapping and classifying streams and water availability, revealed that classifications were correct only about 50% of the time. One goal of the proposed project is to create the Headwaters Intermittency Prediction (HIP) tool. Land managers can use this tool to provide predictions of flow permanence for user-selected headwater streams. The project can also be expanded to predict flow permanence of any stream in the Northwest with near daily/weekly updates based on remote sensing (e.g., snow extent) data availability. The ecological value of the HIP tool will be shown by incorporating HIP output into existing vulnerability assessments for native trout across the Northwest, providing novel insights into the potential consequences of spatial variation in water availability for these species. HIP will also be a timely management tool.