基于控制单元的水环境容量核算研究——以锦江流域为例

CALCULATION OF WATER ENVIRONMENTAL CAPACITY BASED ON CONTROL UNIT——A CASE STUDY OF THE JINJIANG RIVER BASIN

水环境容量核算是流域水环境容量总量分配的重要依据,关系到流域水质目标的实现。控制单元作为流域水环境管理的一个基本实施单位,以其为基础开展水环境容量核算,对于科学制定控制单元容量总量分配具有重要意义。以江西省锦江流域为例,根据水环境容量核算的基本原理,结合锦江流域的污染状况、水质现状和水环境功能区划,对流域各控制单元COD和氨氮的水环境容量进行分析,结果表明,控制单元的水环境容量与其内排污口的分布及功能区水质目标密切相关,COD的水环境容量以高安控制单元的最大,为21 811t/a;其次为上宜控制单元,为21 168t/a;再次为新丰控制单元,为14 493t/a;万载控制单元的最小,为7 607t/a。氨氮的水环境容量在各控制单元的分布特征与COD的略有不同,以上宜控制单元的最大,为790t/a;其次为高安控制单元,为664t/a;再次为新丰控制单元,为462t/a;万载控制单元的最小,为303t/a。

Calculation of water environmental capacity is an important basis in distribution of water environmental capacity,relating to the reachability of water quality target in river basin.It is very important for making distribution plan of water environmental capacity to calculate water environmental capacity based on control units,which are the basic implementation units in water environmental management of river basin.As a case study of the Jinjiang River basin,Jiangxi province,the water environmental capacities of COD and NH＋4-N were both calculated in each control unit according to the calculation methods of water environmental capacity,pollution situation,water quality status and water environmental function division in the river basin.Results showed that water environmental capacities of control unit was closely related to the distribution of drain outlet and water quality target in the function area;the capacity of COD in Gaoan control unit was the largest 21 811 t/a,followed by Shangyin control unit 21 168 t/a,Xinfeng control unit 14 493 t/a and Wanzai control unit 7 607 t/a.The distribution characteristics of NH＋4-N capacity in each control unit were slightly different from that of COD capacity,and Shangyi control unit had the largest capacity 790 t/a,followed by Gaoan control unit 664 t/a,Xinfeng control unit 462 t/a and Wanzai control unit 303 t/a.