Simulation of Water Environmental Capacity and Pollution Load Reduction Using QUAL2K for Water Environmental Management

Xin Qian,Bisheng Xia,Yulei Wang,Rui Ye,Ruibin Zhang,Xingcheng Yuan

doi:10.3390/ijerph9124504

Abstract

In recent years, water quality degradation associated with rapid socio-economic development in the Taihu Lake Basin, China, has attracted increasing attention from both the public and the Chinese government. The primary sources of pollution in Taihu Lake are its inflow rivers and their tributaries. Effective water environmental management strategies need to be implemented in these rivers to improve the water quality of Taihu Lake, and to ensure sustainable development in the region. The aim of this study was to provide a basis for water environmental management decision-making. In this study, the QUAL2K model for river and stream water quality was applied to predict the water quality and environmental capacity of the Hongqi River, which is a polluted tributary in the Taihu Lake Basin. The model parameters were calibrated by trial and error until the simulated results agreed well with the observed data. The calibrated QUAL2K model was used to calculate the water environmental capacity of the Hongqi River, and the water environmental capacities of CODCr NH3-N, TN, and TP were 17.51 t, 1.52 t, 2.74 t and 0.37 t, respectively. The results showed that the NH3-N, TN, and TP pollution loads of the studied river need to be reduced by 50.96%, 44.11%, and 22.92%, respectively to satisfy the water quality objectives. Thus, additional water pollution control measures are needed to control and reduce the pollution loads in the Hongqi River watershed. The method applied in this study should provide a basis for water environmental management decision-making.

Highlights

The Taihu Lake basin is located in the provinces of Jiangsu, Zhejiang, Anhui and Shanghai and has a total area of 36,900 km2
Throughout the river, the concentration of dissolved oxygen (DO) was greater than 5 mg/L, which indicates good water quality because it is better than the water quality objectives
The water environmental capacity was obtained by multiplying the simulation results by the average annual total flow

Summary

Introduction

The Taihu Lake basin is located in the provinces of Jiangsu, Zhejiang, Anhui and Shanghai and has a total area of 36,900 km2 This basin is the core of the Yangtze River Delta region, which has a large population and developed economy. In summer of 2007, a cyanobacteria bloom (the major species are Microcystis, Anabaena and Aphanizomenon of Cyanophyta) occurred in Taihu Lake and the chlorophyll-a concentrations of the water surface exceeding 100 ug/L in many areas resulted in the drinking water source for Wuxi being polluted. This incident affected the daily lives of nearly two million residents, leading to widespread concerns about water quality. From 2007 to 2010, the water quality of Taihu Lake was inferior to Grade V according to the water quality standards of China [1]

Objectives

Methods

Results

Conclusion