Hydrochemical characterisation of a landslide prone area, South Western Ghats, India

Figures & data

Figure 1. Location map of the study area.

Table 1. Descriptive statistics of physio-chemical parameters of MMRB samples.

Parameter	Min	Max	Sum	Mean	SD	Water quality standards
						WHO (2004)	BIS (2012)
pH	4.34	9.20	1208.59	7.70	0.95	6.5–8.5	6.5–8.5
TDS (ppm)	10	480.00	8560	54.52	62.57	1500	500
EC (µs/cm)	7.3	601.80	11052.22	70.40	76.09	1500	-
Temperature^0 C	25	31.00	4546.5	28.96	1.46	-	-
Na^+ (ppm)	0.76	44.53	873.73	5.57	6.85	200	200
K^+ (ppm)	0.01	2.74	51.01	0.32	0.42	12	12
Ca^2+ (ppm)	0.6	34.48	989.85	6.30	5.40	200	200
Mg^+ (ppm)	0	2.39	41.25	0.26	0.35	150	100
Cl^− (ppm)	7.09	42.55	3006.57	19.15	7.02	600	250
SO4^2- (ppm)	40	261.40	9064.9	57.74	27.87	250	400
HCO3^−(ppm)	0.282	317.20	2589.36	16.49	34.35	500	600
CO3 (ppm)	0	0.00	0	0	0.00	-	-
Fe (ppm)	0.0223	0.37	30.44	0.19	0.04	2.0	1.0
TA	14.62	27.89	2296	1	260	-	200
TH	19.75	15.40	3100	4	116	300	300

Figure 2. Box diagram depicting the concentration of various ions in the water samples of MMRB.

Figure 3. Variation in ionic concentrations (mean value) in water samples.

Table 2. Physico-chemical characteristics of water samples.

Spring sample	River sample	Open Well	Bore well	Well type
8.4	7.01	4.34	5.9	pH(min)
8.4	8.7	9.2	8.5	pH(max)
8.40	8.22	7.62	7.73	pH (mean)
10	10	20	50	TDS (min)
10	80	180	480	TDS (max)
10.00	34.29	45.81	240.91	TDS(mean)
19.54	20.17	20.27	7.3	EC (min)
21.12	49.15	255.5	601.8	EC (max)
20.33	33.61	62.73	269.40	EC (mean)
1.53	1.37	0.76	2.05	Na^+ (min)
1.72	4.98	20.25	44.53	Na^+ (max)
1.63	2.78	4.96	20.98	Na^+ (mean)
0.13	0.05	0.01	0.06	K^+ (min)
0.23	0.22	2.74	0.50	K^+ (max)
0.18	0.12	0.36	0.28	K ^+(mean)
3.4	2.5	0.6	1.7	Ca^2+ (min)
10.90	8.41	34.48	31.96	Ca^2+ (max)
7.15	5.76	6.16	12.46	Ca^2+(mean)
0.05	0.04	0.0004	0.00	Mg^2+ (min)
0.06	0.15	2.39	0.66	Mg^2+(max)
0.06	0.09	0.30	0.25	Mg^2+ (mean)
7.09	14.18	7.09	7.09	Cl^− (min)
14.18	28.37	42.55	35.45	Cl^− (max)
10.64	17.73	19.55	19.34	Cl^− (mean)
46.50	46.00	40.00	46.80	SO4 ^2- (min)
48.90	90.40	261.40	113.20	SO4 ^2- (max)
47.70	61.71	58.52	67.72	S04 ^2- (mean)
0.35	0.28	0.28	0.40	HCO3^− (min)
0.35	14.64	58.56	317.2	HCO3^− (max)
0.35	6.60	13.03	101.38	HCO3^− (mean)
0.17	0.13	0.02	0.16	Fe (min)
0.17	0.25	0.37	0.22	Fe (max)
0.17	0.21	0.19	0.18	Fe (mean)
8.00	6.00	6.00	4.00	TH (min)
10.00	18.00	88.00	116.00	TH (max)
9.00	12.00	20.06	38.55	TH (mean)
6.00	4.00	1.00	6.00	TA (min)
6.00	12.00	48.00	260.00	TA (max)
6.00	8.71	10.96	91.09	TA(mean)
−10.83	−4.19	−11.72	−8.54	RSC(min)
−3.34	3.12	4.73	2.32	RSC (max)
−7.09	−1.34	−0.71	−1.94	RSC(mean)
0.74	1.01	0.36	1.29	SAR (min)
1.17	2.54	14.68	20.29	SAR(max)
0.95	1.60	2.70	9.07	SAR (mean)
0.46	0.80	0.004	0	MR (min)
1.73	2.86	58.70	4.56	MR (max)
1.10	1.69	5.00	2.00	MR (mean)
13.58	19.70	8.55	13.78	SSP (min)
30.66	40.25	84.9	82.42	SSP(max)
22.12	31.12	39.25	52.98	SSP(mean)
14.45	20.75	12.17	14.50	%Na(min)
33.72	41.74	85.05	82.48	%Na(max)
24.08	32.08	40.77	53.82	%Na(mean)
0.16	0.25	0.09	0.16	KR(min)
0.44	0.67	5.62	4.69	KR(max)
0.30	0.47	0.80	2.06	KR(mean)
16.31	35.53	25.26	20.93	PI(min)
37.60	76.78	248.00	139.98	PI(max)
26.96	53.38	78.35	79.86	PI(mean)

Figure 4. Hill - Piper trilinear diagram representing the quality of potable water.

Figure 5. Chaddha diagram representing the quality of water in MMRB.

Table 3. Classification of water samples for its suitability based on for irrigation quality standards.

Parameter	Range	Classification	No. of samples within the range
RSC	<1.25	Good	154
	1.25–2.5	Fair	1
	>2.5	Unsuitable	2
SAR	<10	Excellent	151
	10–18	Good	4
	18–26	Fair	2
	>26	Unsuitable
MR	<50	Suitable	155
	>50	Unsuitable	2
%Na	<20	Excellent	13
	20–40	Good	64
	40–60	Permissible	66
	60–80	Doubtful	10
	>80	Unsuitable	4
KR	<1	Suitable	126
	>1	Unsuitable	31
PI	>75	Excellent	60
	25–75	Good	95
	<25	Unsuitable	2

Figure 6. US salinity chart representing the irrigation water quality of the water samples of MMRB.

Table 4. Pearson’s correlation matrix of the physical and chemical parameters of MMRB.

pH

1

TDS

−0.024

1.000

pH

1.000

EC

−0.040

0.899**

1.000

Temp (^0C)

−0.530

0.113

0.123

1.000

Na^+

0.044

0.816**

0.871**

0.081

1

K^+

−0.022

0.360*

0.423*

0.119

0.286*

1

Ca^2+

0.062

0.416*

0.492*

−0.016

0.361

0.417

1

Mg^+

−0.076

0.140

0.137

0.240*

0.042

0.179

0.106

1

Cl^−

0.022

0.252*

0.335*

0.177*

0.269*

0.579*

0.288*

0.202*

1

SO4^2-

−0.164

0.110

0.075

0.088

0.048

−0.018

−1E–04

−0.011

−0.070

1

HCO3-

−0.005

0.603**

0.665**

0.166*

0.731**

0.060

0.249*

−0.002

0.078

0.021

1

CO3^2-

–

–

–

–

–

–

–

–

–

–

–

–

Fe

0.237*

−0.075

−0.087

−0.283

−0.060

−0.0124

−0.068

−0.126

0.0072

2.8E–04

−0.055

–

1

Salinity

0.025

0.249*

0.334*

0.174*

0.267*

0.571*

0.290*

0.202*

0.996**

−0.068

0.078

–

0.009

1

TA

0.018

0.636**

0.667**

0.110

0.721*

0.041

0.240*

−0.023

0.056

0.045

0.976**

–

−0.079

0.056

1

TH

−0.132

0.433*

0.527*

0.187*

0.351*

0.428*

0.834**

0.198*

0.338*

0.031

0.226*

–

−0.059

0.335*

0.194*

1

Figure 7. A, b. Gibb’s diagram depicting the relation between TDS, cations and anions and interpretation of the mechanism for hydrochemistry of MMRB.

Figure 8. (a) Distribution of Ca²⁺ + Mg²⁺ in relation to total cations (TZ) (meq/L), 8 b. Correlation between Na⁺, and K⁺ concentrations (meq/L), 8 c. Relationships between Na⁺ and Cl⁻ in water samples (meq/L) 8 d. SO₄^2- + HCO₃⁻ concentration (meq/L) in relation to Ca²⁺ + Mg²⁺.

Figure 9. Ca²⁺ + Mg²⁺ concentration (mmol/L) and their relation to HCO₃⁻.

Figure 10. (a) Bivariate analysis of Mg⁺/Na⁺ in relation to Ca²⁺/Na⁺, and the correlation between Ca²⁺/Na⁺ and HCO₃-/Na⁺ (Figure 10b) in the water samples, reveals the mixing of ions derived from silicate weathering.

Figure 11. (a) Plot illustrating the relationship between Ca²⁺ and HCO₃- suggests that a majority of the samples exhibit elevated concentration of Ca²⁺ compared to HCO₃-. Figure 11b, depicting the correlation between SO₄^2- and Ca²⁺ reveals a notable concentration of SO₄^2-in the water samples.

Table 5. Schoeller index of water samples of MMRB.

Location number	CAI – 1	CAI – 2
1	−4.03	−0.06
2	−1.56	−0.02
3	−4.77	−0.07
4	−8.02	−0.12
5	−4.12	−0.07
6	−2.84	−0.05
7	−9.02	−0.15
8	−5.63	−0.1
9	−3.8	−0.06
10	−9.63	−0.14
11	−4.04	−0.05
12	−2.28	−0.03
13	−2.18	−0.04
14	−4.42	−0.04
15	−4.64	−0.07
16	−2.71	−0.04
17	−4.56	−0.04
18	−2.55	−0.03
19	−2.23	−0.04
20	−10.41	−0.13
21	−0.77	−0.01
22	−4.84	−0.09
23	−4.28	−0.07
24	−7.53	−0.09
25	−8.96	−0.11
26	−8.28	−0.08
27	−1.74	−0.03
28	−2.87	−0.06
29	−5.56	−0.07
30	−1.93	−0.03
31	−2.88	−0.04
32	−1.39	−0.03
33	−2.22	−0.03
34	−4.57	−0.08
35	−3.64	−0.06
36	−4.88	−0.08
37	−4.24	−0.05
38	−4.68	−0.07
39	−3.48	−0.06
40	−2.18	−0.03
41	−2.17	−0.04
42	−11.98	−0.23
43	−2.12	−0.04
44	−4.01	−0.06
45	−2.71	−0.05
46	−9.07	−0.16
47	−5.11	−0.09
48	−3.52	−0.06
49	−3.71	−0.07
50	−19.03	−0.23
51	−2.44	−0.04
52	−3.93	−0.08
53	−4.13	−0.07
54	−4.1	−0.06
55	−3.15	−0.06
56	−3.94	−0.08
57	−3.14	−0.05
58	−3.01	−0.05
59	−44.08	−0.12
60	−42.06	−0.14
61	−5.13	−0.09
62	−4.51	−0.07
63	−4.37	−0.07
64	−13.78	−0.1
65	−13.32	−0.21
66	−12.7	−0.15
67	−21.92	−0.2
68	−19.4	−0.43
69	−20.03	−0.33
70	−4.7	−0.05
71	−3.14	−0.06
72	−3.75	−0.05
73	−5.16	−0.1
74	−13.22	−0.24
75	−3.77	−0.07
76	−6.71	−0.13
77	−3.63	−0.06
78	−1.59	−0.02
79	−5.68	−0.1
80	−2.57	−0.04
81	−2.88	−0.05
82	−2.5	−0.03
83	−7.72	−0.14
84	−2	−0.03
85	−36.06	−0.5
86	−3.72	−0.07
87	−1.87	−0.03
88	−5.05	−0.06
89	−2.32	−0.02
90	−2.17	−0.02
91	−2.94	−0.03
92	−2.23	−0.03
93	−1.61	−0.03
94	−2.62	−0.06
95	−3.12	−0.06
96	−7.99	−0.19
97	−3.97	−0.08
98	−3.29	−0.07
99	−2.78	−0.05
100	−2.43	−0.05
101	−3.69	−0.04
102	−4.22	−0.09
103	−3.61	−0.06
104	−1.72	−0.02
105	−1.66	−0.02
106	−1.42	−0.02
107	−2.21	−0.05
108	−2.22	−0.05
109	−1.85	−0.04
110	−1.76	−0.04
111	−3.85	−0.05
112	−1.9	−0.04
113	−7.34	−0.15
114	−7.88	−0.14
115	−3.27	−0.07
116	−12.65	−0.24
117	−2.62	−0.05
118	−3.66	−0.05
119	−4.55	−0.06
120	−5.04	−0.09
121	−2.22	−0.04
122	−4.79	−0.09
123	−4.33	−0.07
124	−4.12	−0.07
125	−1.95	−0.03
126	−2.57	−0.04
127	−3	−0.06
128	−3.65	−0.06
129	−2.45	−0.04
130	−1.82	−0.03
131	−2.19	−0.04
132	−3.56	−0.06
133	−4.71	−0.08
134	−6.3	−0.1
135	−4.42	−0.07
136	−1.97	−0.03
137	−4.26	−0.08
138	−5.21	−0.1
139	−4.29	−0.04
140	−3.62	−0.03
141	−2.33	−0.01
142	−4.45	−0.02
143	−6.37	−0.07
144	−7.19	−0.11
145	−13.75	−0.25
146	−8.28	−0.14
147	−14.05	−0.21
148	−5.44	−0.1
149	−7.52	−0.1
150	−1.97	−0.02
151	−7.88	−0.14
152	−16.42	−0.21
153	−3.71	−0.03
154	−3.4	−0.04
155	−44.94	−0.16
156	−5.53	−0.08
157	−2.97	−0.03

Table 6. Weight and relative weight of the water samples of MMRB.

Parameters	Weight (wi)	Relative weight Wi$=\frac{wi}{{\sum }_i^{n}1\mathit{wi}}$
pH	4	0.089
TDS(ppm)	5	0.1111
EC (µs/cm)	4	0.089
Na^+ (ppm)	2	0.044
K^+ (ppm)	2	0.044
Ca^2+ (ppm)	2	0.044
Mg^2+ (ppm)	1	0.022
Cl- (ppm)	3	0.067
SO4^2- (ppm)	4	0.089
HCO3- (ppm)	4	0.089
Fe (ppm)	5	0.11
Salinity (ppm)	4	0.089
TA (ppm)	2	0.044
TH (ppm)	3	0.067

Table 7. Water quality index (WQI) classification.

Sl. No	WQI values	Classification type
1	388.27	Very Good
2	399.62	Very Good
3	404.96	Good
4	453.11	Good
5	367.25	Very Good
6	466.08	Good
7	489.59	Good
8	352.88	Very Good
9	332.24	Excellent
10	427.67	Good
11	462.24	Good
12	377.80	Very Good
13	326.77	Excellent
14	554.26	Poor
15	397.88	Very Good
16	362.68	Very Good
17	590.71	Poor
18	463.23	Good
19	393.16	Very Good
20	388.79	Very Good
21	340.97	Excellent
22	329.39	Excellent
23	398.74	Very Good
24	435.25	Good
25	424.68	Good
26	518.50	Poor
27	350.78	Very Good
28	324.08	Excellent
29	414.50	Good
30	368.15	Very Good
31	352.37	Very Good
32	360.31	Very Good
33	367.03	Very Good
34	405.72	Good
35	381.44	Very Good
36	388.30	Very Good
37	453.70	Good
38	398.99	Very Good
39	341.62	Excellent
40	381.70	Very Good
41	359.94	Very Good
42	433.72	Good
43	372.95	Very Good
44	378.10	Very Good
45	354.81	Very Good
46	374.58	Very Good
47	391.60	Very Good
48	378.87	Very Good
49	381.06	Very Good
50	547.33	Poor
51	388.91	Very Good
52	377.73	Very Good
53	385.12	Very Good
54	404.14	Good
55	463.40	Good
56	399.16	Very Good
57	443.98	Good
58	390.04	Very Good
59	807.15	Very Poor
60	789.99	Very Poor
61	376.57	Very Good
62	415.86	Good
63	427.81	Good
64	577.00	Poor
65	444.58	Good
66	512.65	Poor
67	574.43	Poor
68	381.22	Very Good
69	478.01	Good
70	426.52	Good
71	388.38	Very Good
72	386.36	Very Good
73	228.43	Excellent
74	454.88	Good
75	448.02	Good
76	447.64	Good
77	441.44	Good
78	390.70	Very Good
79	469.18	Good
80	464.44	Good
81	321.26	Excellent
82	360.18	Very Good
83	456.71	Good
84	471.79	Good
85	569.01	Poor
86	397.64	Very Good
87	309.88	Excellent
88	404.59	Good
89	424.63	Good
90	433.21	Good
91	424.39	Good
92	421.43	Good
93	413.40	Good
94	394.07	Very Good
95	413.45	Good
96	423.73	Good
97	479.10	Good
98	415.48	Good
99	344.43	Excellent
100	355.02	Very Good
101	456.23	Good
102	345.67	Excellent
103	456.96	Good
104	399.93	Very Good
105	420.39	Good
106	411.59	Good
107	422.92	Good
108	426.18	Good
109	343.84	Excellent
110	335.51	Excellent
111	398.71	Very Good
112	342.21	Excellent
113	373.34	Very Good
114	426.31	Good
115	340.83	Excellent
116	424.53	Good
117	392.93	Very Good
118	357.22	Very Good
119	373.58	Very Good
120	359.05	Very Good
121	360.77	Very Good
122	373.24	Very Good
123	367.68	Very Good
124	366.91	Very Good
125	323.07	Excellent
126	357.58	Very Good
127	332.33	Excellent
128	329.17	Excellent
129	333.55	Excellent
130	335.61	Excellent
131	328.39	Excellent
132	317.10	Excellent
133	310.98	Excellent
134	327.68	Excellent
135	316.00	Excellent
136	304.90	Excellent
137	323.45	Excellent
138	318.48	Excellent
139	359.00	Very Good
140	344.26	Excellent
141	421.05	Good
142	429.59	Good
143	360.70	Very Good
144	365.87	Very Good
145	401.87	Good
146	360.84	Very Good
147	439.34	Good
148	365.95	Very Good
149	426.94	Good
150	396.60	Very Good
151	412.35	Good
152	483.87	Good
153	382.78	Very Good
154	379.40	Very Good
155	743.67	Very Poor
156	571.80	Poor
157	373.32	Very Good

Table 8. Water quality class assessment by fuzzy membership function.

Water sample class	Number of samples within each class					Total
	Class 1	Class 2	Class 3	Class 4	Class 5
Total Number of sample within class	29	62	54	9	3	157

WHO. (2004). Guidelines for drinking-water quality (3rd ed.). Geneva, Switzerland.

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BIS.10500. (2012). Indian Standard Drinking Water Specification

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Data availability statement

Data are included as electronic supplementary material.