Prioritizing Stream Protection, Restoration and Management Actions Using Landscape Modeling and Spatial Analysis

Watersheds are often degraded by human activities, reducing their ability to provide ecosystem functions and services. While governmental agencies have put forward plans for improving watershed health, resources are limited, and choices must be made as to which watersheds to prioritize and what actions to take. Prioritization tools with sufficient specificity, resolution, and automation are needed to guide decisions on restoration and management actions across large scales. To address this need, we developed a set of tools to support the protection of streams and associated riparian habitats across the state of California. We developed and tested watershed condition estimation models based on bioassessment data, used the EPA's StreamCat dataset to identify stressors, incorporated environmental justice factors and developed reach-specific models to prioritize actions. We applied the prioritization tools statewide and were able to identify 18% of stream reaches that are in good condition but that are most vulnerable to existing stressors and an additional 19% of stream reaches that are degraded and are highest priority for restoration and management. The remaining 63% of stream reaches were prioritized for protection and periodic monitoring or minor remedial actions. The results of this project can help regional stakeholders and agencies prioritize hundreds of millions of dollars being spent to protect, acquire, and restore stream and riparian habitats. The methods are directly transferable by using any regional condition and stress data that can be readily obtained.