The Theory And Application On Water Environment Carrying Capacity

With the rapid economical development in our country, many rivers have faced serious problems such as pollution, dry river, and deteriorate ecological system. These problems are more serious in our country than others. For weighing the harmony degree between human economy society and ecological environment of river, the concept of water environment carrying capacity (simplified as WECC) of river is put forward,, The WECC of river is the important part of natural resources carrying capacity during the development procedure in river basin. Through studying the WECC of river, we can optimize arrangement of water environment and water resource, and harmonize the relationship between ecological construction, people's life and water resource environment. It is very important meaning for sustainable development district.Based on water zoology and water environment, this paper studies the WECC of Sanggan River, in order to assort with the development of environment and economy. Firstly this paper combines the WECC of river with the ecological and environmental water demand, the water environment capacity, and builds some basic theory system of WECC of river. Secondly it builds the index system of WECC by means of thecarrying object(such as population, pollutants, human activities), starting from the carrying media of WECC (water resources quantity and water quality) . Finally it builds the WECC model by system dynamics, taking Sanggan River as an example to study the WECC of river. The main achievements obtained are as follows:(1) This paper builds the concept model of WECC of river, analysing the critical effect factors of WECC of river. It builds the evaluation index system of WECC of river. The index system includes five subsystems of industry, agriculture, population, water resources, water ecology, and water pollution altogether 12 indexes. It decides the weight of each index and subsystem by the method AHP.(2) This paper indicates that the ecological water demand consists of ecological basic flow, water evaporation, inleakage water demand, the environmental water demand consists of the balance of water and sand demand and against-pollution water, starting from the ecological function of river. The ecological water doesn't have request for water quality at computing, while the against- pollution water not only requires to be inflow fresh water, but also calculate background value of water quality for self-clean water.(3) This paper builds the WECC system dynamics model of river, comprehensively considering many factors including economic development, population growth, environmental capacity of pollutant, the river ecological and environmental water demand, the control measures of water pollution and the protective plan of water environment, simulating the indexes in WECC index system. The setup and simulation of system dynamics model of WECC can quantify the control measure of water environment protection, which has practical significance for improving the ecological and human survival environment.