An understanding of the circulation, both ambient and forced, in the vicinity of hydrothermal sources is important not only for physical oceanographic problems, but also for other disciplines. For scientists interested in heat flux from a ridge crest segment the direct measurement of heat flux from hydrothermal sources is not yet feasible. Identification of all the continuous hydrothermal sources is difficult at best, let alone the measurement of each one. Furthermore, episodic tectonic and volcanic activity has been shown to result in massive hydrothermal releases know as megaplumes [Baker et al., 1989; Chadwick et al., 1991]. Although observation of such events is a goal of the RIDGE program it is a task that requires both quick response and luck. However, for both continuous and event sources, estimates of heat flux can be attempted from observations of the water column, which acts as an integrator. The key to this estimation is the availability of observations of sufficient resolution and duration for an adequate budget to be constructed and the availability of suitable models of the flow caused by hydrothermal discharge. The most familiar model of this type is the buoyant plume model of Morton et al. [1956] which has been used numerous times to relate observed plume characteristics such as rise height or centerline temperature to source heat flux [e.g., Little et al., 1987].