New Arizona State University research reveals the extent to which sewage pollution threatens the fragile coral reef ecosystems of West Hawaiʻi Island. The study identifies exactly where sewage-contaminated water is entering the ocean, further damaging coral reefs already impacted by climate change, and endangering human health. The research team used advanced airborne mapping techniques, along with comprehensive field sampling and sophisticated statistical models, to pinpoint locations where high levels of fecal bacteria associated with populated coastal areas are driving worsening contamination. The study provides the critical data needed by government officials and local communities to mitigate this threat and protect the health and biodiversity of coastal ecosystems.