Modelling the influence of rivers The important boundary between river and sea is called the Region of Freshwater Influence (ROFI). A modern ROFI model was developed as a tool to assist scientists and water resource specialists. Climate Change and Environment © Photodisc Rivers carry fresh water, sediment and pollutants out to sea. The ROFI is the region where the pollutants, sediment and other waterborne material will have the greatest impact upon the environment. Waterways that experience high commercial traffic and/or host heavy industry along their banks pose the greatest risk. Numerical modelling is a widely applied tool for simulating physical processes in the environment. ROFI models are particularly challenging in that they must couple both atmospheric (e.g. winds) and water-based (e.g. waves) processes. This generates a heavy computational burden. A group of European organisations combined their expertise and experience to develop a new, fully coupled, 3-dimensional prognostic ROFI model. It can be run at a high level of resolution without overloading the computing equipment. The model accounts for the full range of physical processes, including wind, waves, tides, currents, temperature, salinity, diffusion, sedimentation, stratification, nutrients and contaminants. The model was validated with field data collected from the Rhine River, Clyde Sea and Thermaikos Bay. The conditions vary widely between the three locations and thus tested the robustness of the model. Data were collected year-round in order to include seasonal variability. The mixing effects of wind and waves were found to be the most important physical processes at work. The results were very promising and demonstrated that the new ROFI model can be used effectively as a prognostic tool. Since the completion of the project, the partners have continued to optimise the model and are writing the user manual. They are currently seeking possible marketing and/or licensing agreements and venues to disseminate the findings to a wider audience.
