Environmental flows represent a social-ecological innovation that seeks to sustain healthy riverine ecosystems and human well-being, but capturing Aboriginal interests and values in environmental flow assessments remains challenging. To facilitate the articulation of place-specific cultural, social, and economic water flow needs of Aboriginal peoples, the concept of cultural flows has emerged from the environmental flows literature. An example of a cultural flow comes from the Peace Athabasca Delta in northern Alberta, Canada, termed Aboriginal Flow, which prescribes the minimum water flows in the lower Athabasca River necessary to maintain waterway navigability and prevent disruption to treaty rights. The Mikisew Cree and Athabasca First Nations developed the concept of Aboriginal Flow, which has been advanced through federal and provincial water use decision processes as a potential regulatory limit to be imposed on oil sands water withdrawals. The outcomes of these decision-processes specific to Aboriginal Flow are examined using innovation implementation theory to understand the factors at the individual, structural and cultural levels that act as barriers to and opportunities for integrating Aboriginal perspectives into water policy.