Research by our group has demonstrated that EPT (Ephemeroptera-Plectopera-Trichoptera) taxa are absent from the Colorado River in Grand Canyon, USA, in part due to sub-daily flow fluctuations from dam releases to generate hydropower. In summer 2018, 2019, 2020, and 2022, Glen Canyon Dam releases were experimentally modified to benefit aquatic insect populations downstream. These “Bug Flows” involved standard flow fluctuations (from ~280–480 m3/s) for hydropower generation during weekdays, coupled with steady, low flows on weekends to reduce aquatic insect egg desiccation and mortality. This flow strategy, unprecedented in scope as an aquatic invertebrate environmental flow experiment, was the outcome of direct collaboration between energy distributors, dam operators, and ecologists. In this presentation, we will report on the large-scale, multi-year ecosystem responses of Bug Flows, including their spatial and temporal effects on aquatic insect emergence throughout 400 km of the Colorado River.