Assessment of Water Quality and the Potential for Ecological Sustainability in the Lower Los Angeles River

Considerable interest has arisen among local communities along the lower Los Angeles River regarding the ecological potential of that river reach since the publication of the Lower Los Angeles River Revitalization Plan in 2018. That plan advocated for flood-safe river overlooks and enhancements to the river's confining levees and concrete invert, which will add community benefits and restore a measure of ecological function to benefit native, introduced, and migratory species along this major migration corridor. Complicating a redesign of the Los Angeles River channel is the objective primacy of flood conveyance in densely populated southeast Los Angeles County. Opportunities for community access, climate resilience, and wildlife habitat in the area must maintain the river's existing purpose of fully containing and safely conveying flood flows. This survey presents data to identify opportunities and constraints of revitalization while providing a quantitative baseline for recovery of native species, and support of introduced species, in this highly engineered channel. It includes laboratory analysis of selected water quality constituents in conjunction with field measurement of typical water quality parameters, and direct measurement of water temperatures, completed at two locations on the lower Los Angeles River. This survey is an element of the Lower Los Angeles River Restoration and Access (LLARRA) planning and design effort funded by California's Wildlife Conservation Board and is intended to inform reimagination of the river for the local communities, both human and wildlife, going forward.