Field Observation on Density Current Flux Caused by Bubble Plume in Low Turn Over Rate Reservoirs in Subtropical Region

Abstract

Density current flux due to bubble plum are estimated by using field observation data in a Reservoir located Okinawa Island, Japan. The catchment area Haneji-dam reservoir is small so that the retention time is relatively longer. This characteristics suits to estimate the flux from temporal variation of water temperature vertical profile. Field observation of water temperature and DO were conducted during bubble plume field experiment (five cases) in summer season in two years. Obtained density current flux are analyzed by using some parameters proposed by previous bubble plume researches. The results of this research agreed with some researches conducted in low-Plume number conditions. Empirical equations for estimating the density current flux due to bubble plume in low Plume number condition are proposed for considering practical use of the bubble plume to reservoir water quality preservation system.