Roadmap to Large-Scale Ecosystem Restoration in the Arroyo Seco Watershed

The Arroyo Seco Watershed Assessment (ASWA) provides a framework for the integration of transportation, energy, water resources and restoration concerns in the development and rehabilitation of the Arroyo Seco Watershed, a subwatershed of the Los Angeles River Watershed. The framework culminates with top tier restoration projects spanning the entire watershed from the crest to the confluence with the Los Angeles River, as follows. The Upper Arroyo Seco Channel Restoration is a multi-use project that extends from NASA's Jet Propulsion Lab (JPL) upstream to the watershed divide that will improve water supply, recreation, water quality and ecosystem health. The project is a culmination of years of grassroots planning efforts and analysis focusing on southern California ecosystems. Upstream of JPL, the primary habitat disruptors are impediments to fish passage, forage, rearing and spawning, including anthropogenic structures such as road crossings and water supply diversion and flood control dams. The Central and Lower Arroyo Restoration projects will continue aquatic and upland habitat restoration efforts. Meandering through neighborhoods along the Arroyo Seco, the Lower Arroyo linkages will provide safe pedestrian and cycling links in the highly urban lower reaches of the watershed. ASWA implementation will involve restoration of endangered riverine and upland ecosystem communities, including Riversidian Alluvial Fan Sage Scrub, Southern Sycamore Riparian Woodland, Streambed Riparian, Mule Fat Scrub, Southern Willow Scrub and Coast Live Oak Woodland. Native fish restoration is a key driver for watershed protection efforts and inter-agency cooperation.