Oceanography / Limnology
Numerical Modeling
Visualization and Animation
Specialized Sampling Tools
Acid Rock Drainage
Database/Software Development

The environmental impact of dissolved or suspended contaminants discharged into lakes and oceans can be evaluated using appropriate numerical models to simulate contaminant fate. Sources of contaminants are varied, and can include river run-off, and storm and sewage out-falls. Typically, as in sub-surface discharge of sewage into the ocean, the effluent has a lower density than the ocean waters and will rise to a sub-surface trapping depth, or to the surface, depending on the depth of discharge and the physical properties of the effluent and ocean.

The near-field behaviour of contaminants within an Initial Dilution Zone (IDZ) can be simulated by models such as UM, obtained from the U.S. Environmental Protection Agency. UM calculates the vertical profile of contaminant dilution and plume diameter given the temperature and salinity of both the effluent and receiving waters, the rate of discharge, pipe diameter, and other variables.

The vertical distribution of contaminant within the IDZ calculated by UM is then used to determine the far-field dilution over large regions of a lake or coastal ocean waters using currents obtained from measurements or from a three-dimensional hydrodynamic model.

The result of the simulation is a time-varying, three-dimensional map of contaminant concentration that can be analyzed or visualized using appropriate tools.