The Issue of Modeling the Ecological Processes in Water Bodies
Department of Physical Geography, Yerevan State University, Yerevan, Armenia
In the conception of the sustainable human development, water resources, particularly their current ecological condition, are strategically significant. To carry out an in-depth evaluation of the current ecological condition, as well as to conceive measures against it, it is necessary to establish a system of monitoring the ecological condition of waters. The system must be based on complex criteria, namely, quality and quantity of water resources, water flora and fauna. To obtain reliable information, precise assessment of the ecosystem, to operate activities of the monitoring system effectively, it is important to make systemized observations and analyses of the regime and amount of river runoff, water quality, sources and substances polluting them. To develop a program for ecological monitoring, it is necessary to coordinate the physical, chemical and biological parameters, which aim at identifying and understanding the role and significance of each for the improvement of water ecosystem.
The circumstance of organizing abiotic and biotic observations at the same time and place is rather important. The latter will promote the identification of their interrelation and create a dynamic model within ecosystem.
For the ecosystem approach, long-term programs of monitoring are critical, since they will enable to reveal and evaluate the structure of cycles in ecosystems. It, certainly, is a long-term work and may take years of implementation and considerable expenditures. Having a monitoring system for the ecological condition of water objects, one can create a range of models. Today, throughout the world there are a number of models encompassing many ecological blocks of natural bodies and phenomena. However, when there is need to describe a model of the ecosystem of a natural object, distinguishing it from the whole system, and simultaneously preserving the link, there are always a number of difficulties (Problems of Geography…, 1986).
Let us try and describe a model of the ecosystem of a water object (a river or a lake). To describe it, the following important conditions must be regarded. First of all, it is necessary to link the model of the created ecosystem with other ecological blocks of the global model, which should have the required parameters of entrance and exit.
Secondly, the selected water object should have almost the same natural-climatic conditions to operate the model.
Thirdly, the water object must be located within the physical-geographical area, and not state borders of countries, in order to provide maximum precise forecasts. Of course, the afore mentioned conditions are equally applicable for creating a model of ecosystem for any natural object.
To make the model function, it is necessary to have the mean annual indices of all ecological factors, which may be reflected integrally or in way of indices or several exponents. These exponents allow making differential equations between all the ecological factors and the water object. The equations represent one holistic model, which will function in case of changing any parameter. This model also allows having forecasts based on different scenarios of ecological factors. It is applicable for analogical water bodies as well.
Thus, the created by us model is a holistic system of differential equations, like a live body: any change within the system will directly or indirectly affect the whole ecosystem.