Numerical modeling of fine particle plume transport in a large lake

Abstract

A new concept of Zebra mussel control for power plants is to release Nalco molluscicide H-130 M during intake of cooling water to deactivate the mussels, followed by releasing fine clay to absorb the remaining molluscicide prior to discharge. To predict the fate and impact of a low concentration fine particle plume upon its release to receiving waters, a three dimensional (3D) hydrodynamic and a mud transport model were employed under various wind conditions and different particle settling speeds. The hydrodynamic model was verified against flow velocity vertical profiles measured by two ADCPs (Acoustic Doppler Current Profilers) deployed in the study region during the late fall. Good agreement between the measured and simulated alongshore current vertical profile at the near shore location (1 km) was achieved, however the model had difficulty in replicating the measured offshore current in the near shore region and the velocity vertical profile 5 km offshore. A simplified computational solution using an extended domain of receiving waters with a closed boundary was proposed in this study. Five particle plume transport scenarios were examined with the 3D mud transport model. Generally, in spite of very strong offshore discharge flow, the particle plumes do not extend more than 2 km away from the shoreline in all tested scenarios. The numerical modeling method used in this study can be applied to solve similar coastal zone transport problems if the flow is unstratified and mainly travels along and close to shore.