Modeling the environmental effect of sediment plumes from deepwater mining: Developing a Web-based system, and GIS application

In this study, a numerical model was developed to simulate sediment plumes and its environmental impact from deepwater mining; a Web-based model system was developed for oil spill modeling; and an integration of Geographic Information System (GIS) with numerical modeling was carried out.; A model for simulating the behavior of sediment plumes from deepwater mining and their resulting environmental effect is presented with the complete model formulation and scenario simulations. The sediment transport model includes both the near field (plume dynamics) and the far-field (passive advection-diffusion) phases. The model can handle both upward and downward releases. It also takes into account the possible separation of sediments from the main plume. It is three-dimensional and takes ambient current variations and stratification into account. For simulating the behavior of chemicals sorbed to sediments, three types of chemicals are considered: heavy metal, organic chemical, and mineral. The main difference between the different types is how they partition between being attached to the sediments and dissolved in water. The model simulates the transport of chemicals attached to the sediment as well as the chemicals dissolved in water. The scenario simulations assess the effect on biological life due to entombment by deposited sediments. The light-attenuation and the resulting effect on photosynthesis in the water column due to sediments are also simulated.; Desktop based computer models are commonly used for many environmental hydraulics problems, e.g. a model for simulating sediment plumes, or a model for oil spill fate and transport. A typical desktop model system is served by an input and output interface to communicate with the user. In a desktop model system all components reside in the user's computer. Different from a desktop model system, a Web-based model system is developed with applications oriented towards environmental hydraulics problems in this study. The Web-based model system provides a number of advantages and features that are not available through a desktop system. These advantages range from the improvement in the distribution of the model to the users, user to developer communication, access to distributed data, restriction of some user access to data, different level of accessibility, and multiple users accessing the same data.; Since the environmental hydraulic problems are geographically associated, the integration of GIS with numerical modeling can better support the decision making during emergencies, contingency planning, and risk assessment. Especially when predicting and assessing the ecological impacts in water environment due to certain pollutants and toxic chemicals, the data for the natural and biological resources available in the GIS format can be easily integrated with the simulated results in GIS. In the study, two numerical models are integrated with GIS: the model for sediment plume and its environmental impacts; and the model for oil spill fate and transport and its environmental impacts. In the two applications, GIS works as interfaces for the numerical models, conducting the functions such as inputting data, executing the models and displaying results on specific maps. Beyond that, analytical functions were developed within ArcView using its macro tools to assess the ecological impacts based on the imported natural resource data. The result is a GIS-based customized modeling system for sediment plumes, oil spills, and their toxicity effects.