Fig 1.
Study area and sampling sites in Huong river.
Reprinted from thienhue.gov.vn/geditor.aspx?mapid=10528 under a CC BY license, with permission from Center for monitoring and operating smart cities—Department of Information and Communications—Thua Thien Hue Province, original copyright 2021.
Scheme 1.
Procedure for the river WQI development.
Table 1.
Descriptive statistics for the 11 selected parameters (n = 396) (*).
Table 2.
Eigenvalues, variance percentages and cumulative variances for the components.
Fig 2.
Loading plots: (A) PC1 × PC2 and (B) PC2 × PC3.
Table 3.
Factor loadings for the variables on the first three principal components.
Table 4.
Square loadings, communality values and relative weights for the parameters.
Fig 3.
The linear curve and equation(s) for each parameter to transform the concentration x (in the abscissa) into the grade y (or sub-index q) in the ordinate.
Table 5.
The river WQI values for the ten sampling stations in the years 2017–2020.
Table 6.
The DO, TSS, Fe and TC concentrations, WQI, NSF-WQI and VN-WQI values, and the respective grades for the monitoring session in Nov. 2020 (*).