Calculation of the water environment capacity for a waterfront body
滨江水体水环境容量计算研究

Based on the tide fluctuations,complicated hydrodynamic structure and asymmetric pollutant migration,an asymmetrical coefficient-based calculation method was used to calculate the capacity of the water environment of a waterfront body.In this case,Neijiang of Zhenjiang city was taken as a research area and a 2-D hydrodynamic-water quality model was established.By using the typical daily data of April and August in 2004,the tidal current and the pollutant migration process were numerically simulated.The relationship between pollutants discharged and the pollution area was established,and asymmetrical coefficients for flood season and dry season were calculated(0.18 and 0.25,respectively).The data showed that the environmental capacity in Neijiang was significantly affected by the water level and the hydrological conditions.When the water level changed from 1 to 4 m,the capacity increased by 33.5%.Compared with a common-water year,the environmental capacity in a high-water year could be increased by 110% and in a low-water year,it could be reduced by 32.8%.At the same time,about 84% of the total capacity of the water environment in each year was mainly distributed in May to October.With the asymmetrical coefficient,the presented method reflects the effects of hydrodynamic conditions and the pollutant migration under the impact of tides,so it should be easily and widely useful.