The influence of bounding geometry and rotation on the discharge of buoyant fluid from a turbulent axisymmetric plume in an open-ended channel is examined through an experimental study. Both homogenous and stratified ambients are considered. In the non-rotating channel, the plume rises and spreads as a pair of counterflowing gravity currents at either the free surface (in a homogenous ambient) or at the plume's level of neutral buoyancy (in a stratified fluid). Scaling laws and accompanying experiments indicate that in a homogeneous environment, the surface gravity currents emerging from a channel of widthWand depthHhave a depthhwhich is independent of plume source conditions: