Dilution, distribution and deposition of particulate discharges

Visual Plumes (US Environmental Protection Agency) is a model for simulating surface water jets and plumes (cooling water, sewage, etc). The model calculates the trajectory of discharges, whether it remains submerged or reaches the water surface, and the distribution and dilution of discharges (mixing zone analyses). The model takes into account both vertical layering and water currents in the recipient. In predictions of bacteria concentrations, bacteria mortality is calculated.

Application: Evaluation of the effects of discharges at different depths, daily loads and diffuser configurations. Example: bacteria concentrations and other water quality parameters at recreations areas near sewage outlets. The figure to the left, shows simulated trajectories for two discharge plumes, of which one surfaces and the other remains submerged. The graph to the right shows dilution as a function of distance from the point of discharge.

DEPOMOD and MERAMOD (Scottish Association for Marne Science) are used to predict solids accumulation (feed waste and faeces) on the seabed arising from a fish farm, and associated changes in the benthic faunal community. Read more about these models

Application: Assessing the potential impact of a farm throughout a growing cycle, or if the biomass consent is increased. Site selection support, sustainable production management support and environmental monitoring.

CDFATE (Env. Laboratory, U.S. Army Corps of Engineers) is used for the computation of mixing zone size or dilution for continuous discharges. The model is particularly suitable for submerges discharges that contain a large concentrations of particles (sand, silt, gravel). The model takes into account vertical layering and water currents, discharge properties (rate, pipe diameter, etc) and the different og properties of the particles (weight, particle size distribution).

Application: Prediction of particle distribution and deposition resulting from mining and dredging activities.