Author(s): Xin Jiang; Shiguo Xu; Yuyu Liu; Jianjun Lian; Qingguo Meng
Linked Author(s): Shiguo Xu
Keywords: Water environmental capacity; Dynamic; Ashi River; Frozen period
Abstract: Because of the seasonal change in natural conditions, water environmental capacity has obvious time dynamic characteristics, however, it is unable to reflect this dynamic variation under single designed hydrologic condition. After elaborating time dynamic characteristics of water environmental capacity, this paper puts forward a method to compute the dynamic water environmental capacity. Generally speaking, this method should use a suitable water quality model with corresponding parameters to compute water environmental capacity of various function zones in dynamic designed hydrological conditions. According to this method, a numerical water quality model was set up in the downstream of Xiquanyan reservoir of Ashi River, which is located in Harbin. This model, which is established by the hydrodynamic (HD) & advection-dispersion (AD) module of DHI MIKE11 software, aims at simulating the chemical oxygen demand (COD) and ammonia nitrogen (NH-N) concentration of the observed cross-section in different water function zones and various calculation conditions. Meanwhile, several sensitive parameters were optimized to make the model more reasonable. According to the simulation result, the dynamic water environmental capacity of different water function zones was subsequently calculated by use of the one-dimensional water environmental capacity model. The results show that the COD and NH-H water environmental capacity of various function zones are dynamic, and the water environmental capacity of the frozen period (from November to next March) is far less than the non-frozen period (from April to October). Furthermore, by comparing the water environmental capacity of twelve months on different conditions, both the maximum and minimum water environmental capacity control lines were drawn in several figures. Therefore, the total pollution load of various functional zones will be limited below the maximum or minimum water environmental capacity control line according to requirements, so that there will be more feasible and effective reference for managers.
Year: 2013