Dynamic Modelling of Coastal Water Quality

Growth of anthropogenic load on a coastal zone of the sea in the last years in connection with increase in number of tourists and building of coastal structures has led to an aggravation of many environmental problems. The majority of them are connected with the sea water quality control. Possible prospects of their solution are connected with realization of the concept of "sustainable development" - sustainable coexistence of mankind and the nature, and the basic method of that is the water quality modelling. A plenty of parameters is used to provide the fullness and objectivity of the estimation of quality of superficial waters now. The choice of important for application of 10 parameters from 40-45 proves in the presented model. To increase the accuracy and informative of forecasts for the coastal zone conditions the system-dynamic model has been developed, what allows to estimate the quality of the sea water, including that in the semi-enclosed coastal water areas with the limited water exchange. The model of water quality in the coastal zone includes the equations of deposit concentration changes and chemical substances evolution in the studied areas. The model incorporates joint description of cycles of two biogenic elements - nitrogen and phosphorus. The system is completely defined by the biogeochemical reactions. The sizes of such water areas allow the applying the full mixing and zero-dimensional models of water quality. The circulation of water inside the area is taken into account additionally. Water exchange in the semi-enclosed coastal water areas is defined by the discharge through the open parts of area border. The novelty of the offered model is its adaptation to the specific conditions of semi-enclosed coastal water areas. Then the coastal engineering projects which include the effects of partly enclosed by structure areas with limited water exchange and high intensity of pollution concern. At the same time, the model contains details of the biogeochemical processes to complete modelling of the water quality. The developed system dynamics model is realized in the "PowerSim Studio" media. The data of natural measurements of water quality are applied for the model verification, and the correlated numerical results for the Russian Black Sea coast are presented. The including of the coastal water quality model into the procedures of the integrated coastal area management is also discussed.