The Effect Analysis of Water Diversion on Water Quality Improvement: A Case Study in Urban Lake, China

Abstract

With the rapid progress of society and economy on a regional level, river pollution trends have risen, causing an overwhelmingly poor water quality in urban lakes. In this study, a two-dimensional coupled hydrodynamic and water quality model was employed to assess the enhancement of water quality subsequent to the implementation of water diversion measures in Lake Hou, a representative urban lake located in Wuhan. The model was established based on detailed data collection via survey analysis, model simulation, and joint analysis. The total amount of pollutants in Lake Hou before and after pollution interception and control was compared and analyzed. The observed lake water level, discharge, and water quality parameters, including total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD), were utilized to evaluate the performance of the model. The results showed that the water quality of Lake Hou improved as the recharge flow increased. When the recharge flow was 10 m3/s, TP, TN, and COD improvements were 28.94%, 24.14%, and 14.30%, respectively. When the recharge flow was 15 m3/s, TP, TN, and COD improvements were 33.14%, 27.77%, and 15.57%, respectively. When the recharge flow was 20 m3/s, TP, TN, and COD improvements were 35.74%, 30.10%, and 16.29%, respectively. However, a downward trend can be observed with increasing rates of TP, TN, and COD improvements (%), from 10 m3/s to 15 m3/s, at 4.2%, 3.56%, and 1.27%, respectively. The increasing rates of TP, TN, and COD improvements (%) from 15 m3/s to 20 m3/s were 2.6%, 2.4%, and 0.27%, respectively. This study offers a valuable technical solution for the management of urban lakes.