Maryam Ghashghaie - Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Ali Bagheri - Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

The characteristics of water resources within land ecosystems can be influenced by human activities fundamentally as nutrients are introduced into water bodies. Nutrients enrichment in water bodies especially through sanitary, industrial and agricultural wastewater increases the rate of eutrophication in rivers, lakes and reservoirs. In consequence of entering nutrients such as: Nitrogen (N) and Phosphorous (P) to water bodies in large amounts, algae and water plants develop rapidly. They can influence the quality of water body and the application of water is limited as a result. What is more odors, taste and health problems are arisen due to this phenomenon. Indeed rivers play a crucial role in absorbtion and transportation of pollutants and nutrients. Identifying the source of pollutants and ascertaining the contribution of each source in water pollution, one will be capable of introducing convenient solutions to decline nutrient loading and control eutrophication phenomenon. Nowadays different quality and quantity models have been brought into existence which are capable of recognizing the source of pollutants and suggesting suitable managerial methods to mitigate and control water pollution. In this research Object Oriented methodology based on System Dynamics is applied. It is a tool capable of performing complicated analysis and simulations in which key elements and components of system are recognized as objects then characteristics and relationships of different parts are clarified. Whole model is established determining the corporation and relation between all elements of system. Identifying many factors which intensify the eutrophication rate, proposing and evaluating different strategies as effective solutions to mitigate and control this phenomenon is the aim of this study.

Object Oriented Methodology, system Dynamics, Eutrophication, Watershed, Integrated Management