From deep-sea to the beach: a holistic approach to oil and HNS spill risk management Fernandes R1, Leitão, P2, Braunschweig, F3, Neves R1 1MARETEC – Instituto Superior Técnico – Universidade de Lisboa 2 Hidromod Lda.; 3 Action Modulers INTEGRATION IN MOHID THE PROBLEM Deep offshore drilling; oil and chemical mega-tankers; more than 2000 chemical substances transported by the sea: these are just some examples of new emerging challenges in the context of spill prevention and response activities. The problems are quite different, but the consequences of spill incidents can still converge to common problems: history showed that if something goes wrong offshore, nearshore, in deep-sea or shallow waters, in a chemical or oil tanker - the environment, public health or economy are always subject to some risks. Nevertheless, using several different modelling tools adapted to each kind of scale, system or spill pollution type potentially reduces response effectiveness, avoiding integrated approaches, adapted to the needs and technological possibilities nowadays. MOHID InterfaceWaterAir WAVES This paper intends to answer a different number of recent and upcoming questions regarding preparedness and response to oil and HNS spills, supported by a common modelling system (MOHID) capable of integrating different processes, scales and environments. A wide range of scales (in both aquatic and land environments) requires the consideration of the corresponding transport processes and of interactions between scales. MOHID is a publicdomain open-source system, developed following a modular structure combined with object oriented programing (Neves, 2013). Lagrangian Oil, HNS, Jet www.mohid.com mohid.codeplex.com Sediment MOHID (www.mohid.com) is an environment modelling system dealing with transport and with biogeochemical transformation processes in complex geometries. It was developed to be used by researchers and by professionals and to be applicable to a large range of scales and physical conditions. Researchers require tools able to test hypotheses and compare options. Professionals require efficiency for quick results production. Hydrodynamic Turbulence GOTM BENTHOS MODELLING APPROACH Lagrangian Approach: Oil and HNS modelling components are integrated on MOHID lagrangian transport module, where simulated pollutants are represented by a cloud of discrete particles (or super-particles) advected by wind, currents and waves, and spread due to random turbulent diffusion or mechanical spreading. Offline / Online: This model has the ability to run integrated with hydrodynamic solution, or independently (coupled offline to metocean models), being this last one the commonly adopted option for integration in the developed operational tools (to reduce computation time, taking advantage of metocean models previously run). HNS modelling component: The freshly new chemical spill module component implemented in MOHD estimates the distribution of chemical on water surface, shorelines, atmosphere, water column, sediments and seabed. Spilled mass is tracked through phase changes and transport. Model tracks separately evaporated or volatilized particles, floating chemical, entrained droplets or suspended particles of pure chemical, chemical adsorbed to suspended particulates, and dissolved chemical. 3D underwater view of a cloud of particles simulating a surface chemical spill Multi-mesh solution: MOHID lagrangian transport module includes a multi-mesh functionality, allowing particles to move along different model domains / grids. The main advantage on this approach is the possibility of using simultaneously multiple high resolution models when and where available, together with other models with lower resolution, in the same spill simulation. In this way, one can take advantage of several different operational modeling systems, using them in an integrated fashion. MOHID lagrangian computes the needed interpolations onthe-fly, and limit these interpolations to a specific spatial area where lagrangian particles are present (Fernandes, 2013). This integrated and holistic approach allows MOHID to simulate spills from deep sea blowouts and transport it to a beach in the same simulation. A cloud of particles being advected across three horizontally aligned grids. The grids order of priority is the following: blue, red and grey (source: Janeiro et al., 2014) APPLICATIONS AND CASE STUDIES Several different environments, processes and user interfaces have been tested with MOHID lagrangian component along the last decade. Some of these case studies using oil & inert spill module are presented. Prestige accident (after sinking): Comparison of the forecasted position with MOHID (coloured spots) with overflight observed position (black circles) (source: Carracedo et al., 2006) Operational oil spill scenario simulated during the fuel diesel removal operations from the Costa Concordia ship (source: Janeiro et al., 2014) 50 um (0.05 mm) Blowout simulations in Caribbean Coast (Colombia): Particle depths with different oil droplet diameters. 3D (above) and XY (below) views source: Leitão et al., 2013 References: Tagus estuary (Lisbon): Drifting buoys position (represented by markers with color scale representing time after release) vs. MOHID floating particles (in one instant) considering different turbulent diffusivities (represented by polygons with different colors) (source: Fernandes et al., 2013) ARCOPOL / Aquasafe Oil Spill Simulator: Oil spill simulation from satellite-detected oil slick (Polygons from EMSA’s CLEANSEANET service can be imported to this operational system and used as initial spill position) ARCOPOL / MOHID Studio’s Dynamic Risk Tool: Shoreline contamination risk from ship-source oil spills along Portuguese continental shelf (this tool is able to compute realtime and historical risks using space-time variable data layers as metocean forecasting systems, AIS information, and oil spill model results based on ship trajectories) Acknowledgements: This research has been partially supported by ARCOPOL PLATFORM (contract nr. 2013-1/252) - funded by EU Atlantic Area) Carracedo, P., S. Torres-López, M.Barreiro, P. Montero, C.F. Balseiro, E. Penabad, P.C. Leitão and V. Pérez-Munuzuri (2006). Improvement of Pollutant Drift Forecast System Applied to the Prestige Oil Spills in Galicia Coast (NW of Spain): Development of an Operational System. Marine Pollution Bulletin, 53: 350360 Fernandes, R., Neves, R., Viegas, C., Leitão, P. (2013). Integration of an oil and inert spill model in a framework for risk management of spills at sea - A case study for the Atlantic area. 36th AMOP Technical Seminar on Environmental Contamination and Response. Halifax, Nova Scotia, Canada. pp. 326-353. Janeiro J, Zacharioudaki A, Sarhadi E, Neves A, Martins F. (2014). Enhancing the management response to oil spills in the Tuscany Archipelago through operational modelling. Marine Pollution Bulletin, 85(2): 574-589 Leitão, P C, Malhadas, M, Ribeiro, J, Leitão, J, Pierini, J, Otero, L.(2013). An overview for simulating the blow out of oil spills with a three-dimensional model approach (Caribbean Coast, Colombia). Ocean modelling for coastal management – Case studies with MOHID. M. Mateus & R. Neves (eds.), IST PRESS, pp.97 - 115 Neves, R. The MOHID Concept. (2013). Ocean modelling for coastal management – Case studies with MOHID. M. Mateus & R. Neves (eds.), IST Press, pp. 1-11
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