Study on the Water Environment Capacity of Tuohe River in Suzhou City

The water-environment capacity is an important base for making the river pollution control,weakening the pollution source and realizing the water-function target.Analyses on the present situation of water quality of Tuohe River in Suzhou City are conducted.The hydrological characteristics,the contamination characteristics and the water environment status were investigated.Combined with the design procedure of the water environment capacity, one-dimensional water quality model was selected to calculate and analyze the water environmental capacity of Tuohe River in Suzhou.The results showed that the BOD_5 of water environmental capacity is 1231.16t/ a,the COD_(Cr) of water environmental capacity is 4289.73t/a,and the NH_3-N of water environmental capacity is 377.3t/a.Though the current water quality of Tuohe River was good in general,most of the river's sections have residual water environmental capacity and it is necessary for Tuohe River in Suzhou to carry out strick total pollution reduction plans(especially for COD)in future with the population growth and socio-economic development.