Prioritizing road work to achieve landscape-scale restoration within the Cedar River Watershed, Washington

The Cedar River Municipal Watershed (366 km²) supplies water to over a million people in the Seattle metropolitan area but is also being managed as an ecological reserve under a federal Habitat Conservation Plan (HCP).  An important component of the HCP is the decommissioning of approximately 22 km of road per year to reduce impacts of a 930 km road system built to harvest timber prior to the HCP.  We developed a tool for identifying and prioritizing roads for improvement and decommissioning that supports both water supply operations and landscape-scale restoration strategies within the watershed.   In order to protect or restore ecosystem processes and functions affected by the road network, we established a series of clear, quantifiable restoration goals, including: increase of habitat connectivity, maintenance of natural woody debris recruitment and hydrologic flow processes, reduction of road-derived fine sediment delivery to streams, and reducing the potential for road-generated landslides.  Road segments currently impacting key habitat elements were identified and prioritized based on two criteria applied to each goal:  (1) sensitivity of habitat to road-related impacts and (2) likelihood that a road segment is negatively impacting key habitats.  Using this approach, we have identified 431 road segments totaling 120 km which are significantly impacting key ecological processes and functions and preventing the attainment of multiple restoration goals.  By fixing road-related ecological problems that propagate their effects via disruption of natural patterns of terrestrial and aquatic connectivity, we hope to maximize benefits of restoration at both local and landscape scales.