The concentration of dissolved oxygen in water plays a vital role in biogeochemical cycling and aquatic ecosystem function. In warm climates, temperatures cause thermal stratification in hydroelectric reservoirs preventing mixing and leading to deoxygenation of waters in the hypolimnion of the reservoir. Hydropower generation with turbines extracting water at depth with low dissolved oxygen content has a negative impact on the downstream river ecosystem. Legislation (Canada, USA and elsewhere) now requires minimum dissolved oxygen concentration limits to be met in rivers. Technological approaches to re-aerate the water in the turbine with the injection of air bubbles is a solution that also reduces vibrations when operating the turbine at part load, which is increasingly used to balance the grid due to intermittent renewable energy loads. Retrofit technologies to re-aerate flows are preferred, as they have less impact on revenue. Andritz Hydro Canada implemented one of the first prototype in-flow aeration systems using angled baffles at the Canyon Ferry Generating Station, demonstrating the viability of this system. Building on an initial collaborative exploratory study, Andritz Hydro aims to optimise the angled baffle technology, understand the physical processes of the two-phase flow of the swarm of bubbles drawn into the aspirator flow and quantify the subsequent dissolution of oxygen in the flow. Similarity laws will be developed and the ultimate goal is to support the development of a computer model to predict prototype operations. Andritz Hydro Canada will position itself as a leader for hydroelectric projects with environmental requirements such as dissolved oxygen levels, capable of ensuring the required regulatory requirements (or better) for dissolved oxygen while optimizing turbine performance.