Author(s): W. E. Frick; P. J. W. Roberts
Linked Author(s):
Keywords: Plume; Outfall; Diffuser; Initial dilution; Public domain software; Marine; Freshwater; Mathematical model
Abstract: Visual Plumes (VP), and its predecessor DOS Plumes, has been used for over 20 years by design engineers, environmentalists, regulators, and researchers to simulate the effects of wastewater outfalls on marine and freshwater receiving waters. Part of its appeal can be attributed to its public-domain availability; the US Environmental Protection Agency (USEPA) freely distributes the original software through the Center for Exposure Assessment Modeling (CEAM) based in Athens, Georgia. VP is valued for its flexibility, including the ability to easily compare three different dilution models (DKH, NRFIELD, and UM3), its user-friendly interface, and its graphical output that enables visualization of the results and ready comparison of alternative scenarios. Many common outfall configurations, including single- and multi-port designs in stratified and unstratified, flowing and stationary ambient receiving waters, can be set up and simulated. Time-series input enables analysis of long time series to rapidly determine critical conditions. The user-friendly interface makes it easy to quickly set up and modify the input, facilitating what-if and sensitivity analyses. Variables can be entered in many different systems of units, and far field fate and transport and decay, such as due to bacterial mortality, can also be simulated. Over the years users have found new uses for VP and identified issues that, since about 2003, have led the authors to modify and improve VP, while the CEAM version remained unchanged. Furthermore, Roberts updated NRFIELD to include the latest experimental data outside of the VP framework. To restore the inclusive model functionality to VP, starting in 2014, Frick and Roberts collaborated on recoding NRFIELD for VP. The present paper describes the work to translate (recode) the standalone version of NRFIELD and reintegrate it into VP. Other important changes also are described, such as code that prevents the user from inadvertently interfering with another instance of VP running. A MultiLinear Regression exercise is sketched out to illustrate how VP results might be used to help analyze related problems, for example, forecasting surf-zone concentrations near offshore outfalls. Finally, recognizing the value of public-domain models, information is provided to enable freely downloading the software. Some comments about model comparisons and capabilities also are presented.
Year: 2016