Numerical Modeling For Assessing Marine Biological Resources Damage Caused By Spilled Oil Based On GIS

Quantitative assessment of the marine biological resource damages resulting from oil spill accidents, which also plays a prior role in the process of claiming maritime arbitrations and compensations, has taken involving efforts of the scientists of the field. Throughout the overview of marine oil spill compensation in China, and analysis the state-of-the-art of research and application of the marine ecology damage assessment techniques and methods, This paper, taking the establishment of a framework which assesses the biological resources damages resulting from marine oil spill using numerical modeling, focusing on the development and application of numerical assessment models and software system. The major contents and significant results have been achieved are as follow:1. A computer assessment scheme for biological damages resulting from oil spill in marine environment was proposed. Based on the investigating or monitoring data and related information of the accident, the tidal current simulation module and the oil spill transport and fate model provide sufficiently accurate predictions, such as hydrodynamic environment and the spatiotemporal distribution of the spilled oil, to achieve the requirement of the biological exposure module and acute toxicity module. The latter two modules are used to simulate the response of different marine species under such an environment, as well as the acute toxicity effects of the spilled oil acting on them, and caluate quantitatively the marine biological damage.2. A three-dimensional oil spill trajectory and fate model (OSTFM) was developed. The model can simulate instant or continual release from one spill site, and continuous release from moving spill site or mutitiple spill sites by using Langrange particle tracking method. The model can also simulate the transport and weathering processes of spilled oil such as evaporation, emulsification, dispersion, dissolution and so on, and the spatiotemporal distribution of spilled oil on the sea surface and in the water column.3. An oil spill biological acute toxicity model (OSATM), which can predict the time-concentration-effect relationship between oil pollutant and marine organism, was developed based on the statistic and regression of the acute toxicity test data. To provide the basical data for numerical modeling and actual oil spill accident assessment, the oil toxicity database was also prelininary built based on two types of datasets, i.e. the toxicity data from the acute toxicity tests of different marine organisms carried out in our labrotary, and the toxicity data recorded in the literatures.An oil spill biological exposure model (OSBEM) was subsequently developed. The marine orgranisms, including plantonic, marine fishes and benthos, are represented by a large number of Langrange particles respectively. The exposure time and concentration of each particle will be recorded during the simulation of tracking its movement in the polluted environment. The biomass losses of the marine organisms are calculated by the OSATM model. As for the marine wildlife (sea birds and marine mammals), the killed percentages are calculated based on the probability of being oiled by the surface oil slicks which exceeding a threshold thickness.4. An oil spill model activex control (OSMAC), which integrates the numerical assessment models and data management and visualization, was developed with the COM component technique. On the basis of the OSMAC, the marine oil spill biological resource damage assessment system (OILASSESS) was designed and developed using Visual C++, GIS technology, component technique and numerical simulation technology. The model system not only has the basic GIS functions, but also the functions of tidal current simulation, oil spill transport and fate prediction, and biological resource damage assessment caused by oil spill accidents.5. The OILASSESS model system was used to assess the biological resource damage assessment caused by oil spill accidents. In the two cases study, i.e. Yangchenghu spill accident and Arteage spill accident as the first case, and the Qiandaoyou1 spill accident as the second case, the surface oil slicks and subsurface oil concentrations simulation results are in good agreement with field investigation and observation data, the biological resource damage assessment results are proved more objective and reasonable than that of the expert evaluation method. The applications show that the model system is an effective tool for marine oil spill ecology damage assessment.Lacking of effective quantitative assessment techniques for marine oil spill accidents ecology damage compensation inland, the research of this paper provides valuable theory references and experiences in perfecting and improving the assessment techniques for the marine ecological damage assessment.