Simulation of hydrodynamics and water quality in Xi'an Yanming Lake China

4th International Conference on Water Resource and Environment

地球科学;生态环境科学

Su, J.L.^1 ; Wang, Y.^1 ; Chen, J.^1 ; Zhang, Q.L.^1 ; Zhang, Y.^1 ; Guo, Y.J.^1

State Key Laboratory of Eco-hydraulic Engineering in Shaanxi, Xian University of Technology, Xian, Shaanxi

710048, China^1

关键词: Advection-dispersion equation;    Back-propagation Neural Net;    Concentration fields;    Distribution characteristics;    Response characteristic;    Time-average velocities;    Water environments;    Water quality modeling;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/191/1/012066/pdf
DOI  :  10.1088/1755-1315/191/1/012066

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

In order to facilitate works of water environment management in Yanming Lake Xi'an Shaanxi, the MIKE 21 hydrodynamic model coupled with the advection-dispersion equation was employed to develop a water quality model to investigate the characteristics of the flow field on the conditions of different wind and to simulate the variations of pollutants, which were Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphate (TP). The Back propagation Neural Net (BPPN) approach was introduced to utilize the results of simulation to evaluate water quality in Yanming Lake. Additionally, based on the distribution characteristic of pollutants, three scenarios for external pollutants' load reduction were proposed. Response Characteristics of water quality after implementation of different scenarios was conducted. The results showed that the time-average velocity value ranged from 0 to 0.01 m/s in Yanming Lake on the condition of both no wind and southwest wind. Six circulations could be induced by southwest wind in the flow field. The time-average COD concentration field could be divided into three regions, whose concentration was 12-13 mg/L, 13-14 mg/L, and 14-15 mg/L respectively. Time-average TN concentration field consisted of two regions, whose concentration was 2.85-3.00 mg/L and 3.00-3.15 mg/L separately, and TN concentration exceeded the standard of Grade V (GB3838-2002). Time-average TP concentration field had no significant zoned phenomenon and its concentration ranged from 0.040 to 0.048 mg/L. Results from evaluation of water quality indicated that water quality was in the standard of inferior Grade V. Additionally, water quality will be better improved after implementation of Scenario 2 rather than Scenario 1 and 3.