Assessment of Groundwater Quality Using Water Quality Index from Selected Springs in Manga Subcounty, Nyamira County, Kenya

Table 4

Unit weight, relative weight, quality rating, and subindex values.

Parameter	Weight		SP1		SP2		SP3
	Wu	Wr	Qr	PIs	Qr	PIs	Qr	PIs
pH	4	0.06897	260	17.9322	380	26.2086	320	22.0704
Turbidity	3	0.05172	18	0.93096	16.8	0.86890	21	1.08612
Nitrate	5	0.08621	6.8	0.58623	8.8	0.75865	12	1.03452
Phosphate	3	0.05172	0.035	0.00181	0.06	0.00310	0.02	0.00103
Calcium	3	0.05172	5.3	0.27412	4	0.20688	6	0.31032
Magnesium	3	0.05172	1.2	0.06206	0.9	0.04655	0.67	0.03465
Chloride	5	0.08621	1.2	0.10345	0.8	0.06897	0.4	0.03448
Fluoride	5	0.08621	0	0	0	0	0	0
Sulphate	5	0.08621	1	0.08621	0.5	0.04311	0.5	0.04311
Iron	3	0.05172	0	0	0	0	0	0
Total phosphorous	3	0.05172	14	0.72408	18	0.93096	8	0.41376
Total hardness	3	0.05172	3.33	0.17223	2.67	0.13809	3.33	0.17223
Total alkalinity	4	0.06897	4	0.27588	3.4	0.23450	4	0.27588
TDS	4	0.06897	2.5	0.17243	2.2	0.15173	2.3	0.15863
Coliforms	5	0.08621	0	0	0	0	0	0
WQI				21.32		29.66		25.64