Thermal Plume Monitoring with Temperature Recording Drogues

Instrumented drogues were used to measure temperature as a function of time and position in the thermal plume from a power plant. During a two week period in June, 1975, 92 temperature recording drogues were deployed in the heated water discharge from the Pilgrim Power Station located near Plymouth, Massachusetts. Results of the measurements indicate a rapidly varying near-field temperature distribution which varied primarily as a function of winds and tides and the currents associated with them. The tracks followed by individual drogues were highly variable and showed no discernible concentration in any particular area. Plots of temperature versus time and temperature versus distance show that most of the data fall into well defined envelopes which delineate a range of dispersion rates at the site. Comparison of the drogue data with mathematical modeling results obtained by Adams, et. al. (1975) illustrates their usefulness in model verification and calibration.