The pumping of less dense surface water into a deep layer, also termed artificial downwelling (AD), has demonstrated its effectiveness in ventilating basin water in a few fjords. Building on a previous experiment in By Fjord, we established a well-calibrated far-field hydrodynamic model to simulate bottom water circulation caused by AD implementation. Our simulations suggest that (1) laterally closed boundaries are crucial for AD to cause spatially uniform compensatory downwelling in the bottom water and that (2) dissolved oxygen delivered through downwelling can be sourced from both surface waters and below the pycnocline to enhance oxygen levels effectively. We propose a physical oxygen budget model to predict the temporal variability of deep-water oxygen levels, offering guidelines on the number of pipes and flow rates required for large-scale oxygenation. For small fjords (∼1 km2), a few pipes (each has a flow rate of 1 m3 s−1) may suffice, while medium-sized basins like Chesapeake Bay (∼1000 km2) may require several hundred pipes.