Calculation Methods And Application On Surface Water Environmental Capacity In Small River Basin

Water in small river basin is being polluted badly, which directly worsen the water quality in mainstream. The focus of the water pollution prevention and control is exactly the problem about the calculation and application of water environmental capacity. However the natural and social conditions in small river basin greatly differ from those in big river basin or urban area, so it needs to find out more simple ways to calculate and manage the water environmental capacity in small river basin, and to provide scientific guidance for the water pollution prevention.On the base of the correlative documents, the one-dimensional calculation model for water environmental capacity model was founded in this paper, which was used to calculate the water environmental capacity of the Nan River Basin in Qionglai City in low flow period as an example. The main contents and results of this study are as follows:1. According to the characteristics of small river basin as well as the principles of fairness and practicality, the water environmental function ending control method and the one-dimensional water-quality were adopted. The calculated water environmental capacity is expressed by the amount of contamination passing the control cross section in unit time. The passed amount of contamination will be limited by the water-quality demand at the cross in percent form and accordingly the quantity of pollutant discharge will be limited at the same percent without quantitative conversion, so the work can become simpler.