Spatial interpolation of water quality index based on Ordinary kriging and Universal kriging

Figures & data

Figure 1. The geographical locations selected for the current analysis.

Table 1. Descriptive statistics of Physicochemical & Heavy metals of observed samples.

Physicochemical and heavy metals	Mean	Standard deviation	Physicochemical and heavy metals	Mean	Standard deviation
pH	7.72	0.17	Zn	0.03	0.05
EC	41.96	16.39	Cu	0.0020	0.0011
Hardness	74.31	15.68	Fe	0.06	0.04
Cl	16.2	10.96	Cd	0.04	0.01
TDS	19.52	7.78	Cr	0.08	0.05
SO4	6.19	4.13	Ni	0.06	0.04
NO3	3.75	1.97	Mn	0.09	0.03
COD	108.88	29.36	Pb	0.51	0.32
HCO3	40.69	9.24	AS	0.001	0.001
DO	3.76	0.69

Table 2. Categorization of water on the basis of WQI.

WQI Categories	Categories	Frequency	Percentage (%)
WQI < 50	Excellent	00	0
50–100	Very good	18	69.23
100–150	Poor water	08	30.77
150–200	Very poor	00	0
WQI > 200	Unsuitable for drinking	00	0

Figure 2. Variogram envelope for WQI without Trend.

Figure 3. Circular variogram fitted to emperical variogram for OK and powered exponential variogram fitted to empirical variogram for UK.

Figure 4. Prediction map of WQI by using OK and prediction error map of WQI by using OK.

Figure 5. Prediction map of WQI by using UK and prediction error maps of WQI by using UK.

Table 3. Prediction techniques with their corresponding RMSPE.

Methods	OK	UK
RMSPE	14.07313	12.75351

Data Availability statement and codes

The data and codes used for the preparation of the manuscript are available with the corresponding author and can be provided upon request.