A Foundation for Integrated Water and Species Policy: Wastewater Treatment Plant Effluent Overlaps With Wildlife in California Watersheds

The spread of human settlement has imperiled fresh waterbodies; however, it has also led to the generation of novel water conservation strategies, including the reuse of treated wastewater, or effluent. Effluent reuse is an increasingly common aspect of watershed management, and thus far, research has been concentrated on its effects to water quality and efforts to describe effects to wildlife species have been relatively piecemealed. In this study, we evaluate the overlap between wastewater treatment plants and federal and state-listed endangered and threatened wildlife species in order to present a holistic view of the intersection of effluent and species management and the potential need for effluent considerations in species conservation. We show that there is substantial overlap between the presence of species and the presence of treatment plants in California watersheds, and with this overlap, a large potential for unintended consequences. As such, species conservation goals should be considered when making decisions related to effluent reuse.