Environment and Ecology Research Vol. 10(5), pp. 561 - 571
DOI: 10.13189/eer.2022.100504
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Trend Analysis on Water Quality Index Using the Least Squares Regression Models

Iskandar Shah Mohd Zawawi ^1,*, Mohd Ridza Mohd Haniffah ², Hazleen Aris ^3
1 Faculty of Computer & Mathematical Sciences, Kompleks Al-Khawarizmi, Universiti Teknologi MARA 40450 Shah Alam, Selangor, Malaysia
² Department of Water and Environmental Engineering, School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
³ Institute of Informatics and Computing in Energy, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia

ABSTRACT

River water pollution requires continuous water quality monitoring that promotes the improvement of water resources. Therefore, the trend analysis on water quality data using mathematical model is an important task to determine whether the measured data increase or decrease during the time period. This paper is intended to highlight the applicability of the least squares regression models to fit the WQI data of the Skudai River, Tebrau River and Segget River located in Johor, Malaysia. As per the 12 years of trend analysis, the data of WQI are collected from the Environmental Quality Reports 2009-2020. The least squares method is utilized to estimate the unknown constants of the linear, quadratic, cubic, polynomial of degree four and degree five regression models. The advantage of using proposed models is that it can be implemented easily even on relatively low computational power systems. The results show that the higher degree polynomial model fits the data reasonably well, in which the polynomials of degree 4 and 5 have lowest average error. Assessment of actual and predictable values of WQI shows that the trends in WQI for all study areas are downward year after year.

KEYWORDS
Water Quality Index, Trend Analysis, Regression Models, Least Squares Method

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Iskandar Shah Mohd Zawawi , Mohd Ridza Mohd Haniffah , Hazleen Aris , "Trend Analysis on Water Quality Index Using the Least Squares Regression Models," Environment and Ecology Research, Vol. 10, No. 5, pp. 561 - 571, 2022. DOI: 10.13189/eer.2022.100504.

(b). APA Format:
Iskandar Shah Mohd Zawawi , Mohd Ridza Mohd Haniffah , Hazleen Aris (2022). Trend Analysis on Water Quality Index Using the Least Squares Regression Models. Environment and Ecology Research, 10(5), 561 - 571. DOI: 10.13189/eer.2022.100504.