Assessment of Water Quality Profile Using Numerical Modeling Approach in Major Climate Classes of Asia.

Muhammad Mazhar Iqbal,Jung Lyul Lee,Hafiz Umar Farid,Muhammad Shoaib

doi:10.3390/ijerph15102258

Abstract

A river water quality spatial profile has a diverse pattern of variation over different climatic regions. To comprehend this phenomenon, our study evaluated the spatial scale variation of the Water Quality Index (WQI). The study was carried out over four main climatic classes in Asia based on the Koppen-Geiger climate classification system: tropical, temperate, cold, and arid. The one-dimensional surface water quality model, QUAL2Kw was selected and compared for water quality simulations. Calibration and validation were separately performed for the model predictions over different climate classes. The accuracy of the water quality model was assessed using different statistical analyses. The spatial profile of WQI was calculated using model predictions based on dissolved oxygen (DO), biological oxygen demand (BOD), nitrate (NO3), and pH. The results showed that there is a smaller longitudinal variation of WQI in the cold climatic regions than other regions, which does not change the status of WQI. Streams from arid, temperate, and tropical climatic regions show a decreasing trend of DO with respect to the longitudinal profiles of main river flows. Since this study found that each climate zone has the different impact on DO dynamics such as reaeration rate, reoxygenation, and oxygen solubility. The outcomes obtained in this study are expected to provide the impetus for developing a strategy for the viable improvement of the water environment.

Highlights

Climate characteristics have a significant impact on the spatio-temporal variation of surface water quality
The results showed that there is a smaller longitudinal variation of Water Quality Index (WQI) in the cold climatic regions than other regions, which does not change the status of WQI
Purposes,ininthis this study each length of the spatial profile was divided into an number of Figure presents the spatial effects of the water quality concentration on equal number of WQI segments

Summary

Introduction

Climate characteristics have a significant impact on the spatio-temporal variation of surface water quality. Deteriorating water quality presents a serious problem to the water security of many zones in different climatic classes. The impact of climate change on water stressors has compounded further the challenge of the planning and prediction of water quantity and quality within the hydro-ecosystems in different climate regions. It has been acknowledged that the impact of climate change will influence the quality of water through human activities and complex natural mechanisms over different regions [4,5,6]. Variation in climate may have an indirect influence on surface water health through changes in land scape pattern [7,8,9,10]. A deterioration of water quality has been observed in a number of studies on the influence of water quality due to climate change, on water pollutants and their physio-chemical characteristics—such as DO, total suspended solid (TSS), ammonia (NH3 ), and turbidity—within the changing hydrometeorological

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Conclusion