Watershed Prioritisation of Drainage Basins Based on Geomorphometric Parameters, Neyyar Watershed, India

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Methods or formulae of parameters used in this study_

Parameter	Formulae or methods	References
Methods or formulae for linear parameters
Stream order (U)	Hierarchical rank	Strahler (1964)
Stream number (Nu)	Nu = Nu1 + Nu2 + ··· + Nun	Horton (1945)
Stream length (Lu)	Lu = Lu1 + Lu2 + ··· + Lun	Horton (1945)
Mean bifurcation ratio (Rbm)	Average of bifurcation ratio of all orders	Strahler (1957)
Bifurcation ratio (Rb)	Rb = (Nu / Nu+1)	Strahler (1964)
Mean stream length ratio (Rlm)	Average of the steam length ratio of all orders	Strahler (1964)
Stream length ratio (Rl)	Rl = (Lu / Lu−1)	Horton (1945)
Drainage density (Dd)	Dd = (ΣLu) / A	Schumm (1956)
Stream frequency (Fs)	Fs = (ΣNu) / A	Schumm (1956)
Length of overland flow (Lo)	Lo = (1 / (2Dd))	Horton (1945)
Drainage texture (Dt)	Dt = (ΣNu) / P	Schumm (1956)
Drainage intensity (Di)	Di = (Fs / Dd)	Faniran (1968)
RHO coefficient (ρ)	(Rlm / Rbm)	Horton (1945)
Methods or formulae for relief parameters
Maximum elevation (H)	GIS software	–
Minimum elevation (h)	GIS software	–
Relief (Bh)	Bh = H–h	Strahler (1952a)
Ruggedness number (Rn)	Rn = Bh × Dd	Strahler (1952b)
Relative relief (Rhp)	Rhp = H × 100 / P	Melton (1957)
Methods or formulae for areal or shape parameters
Perimeter of watershed (P)	GIS software	–
Area of watershed (A)	GIS software	–
Compactness coefficient (Cc)	Cc = (P / 2(πA)0.5)	Horton (1945)
Form factor (Ff)	Ff = (A / Lb2)	Horton (1945)
Elongation ratio (Re)	Re = (2 (A / π)0.5) / (Lb)	Schumm (1956)
Watershed length (Lb)	Lb = 1.312 × A0.568	Nookaratnam et al. (2005)
Circulatory ratio (Rc)	Rc = 4πA / P2, where π = 3.14	Miller (1953)
Method or formula for hypsometric analysis
Elevation-to-relief ratio (E)	E = (Mean elevation − minimum elevation / Maximum elevation − minimum elevation)	Pike and Wilson (1971)

Final ranking of morphometric analysis_

Parameter	SW1	SW2	SW3	SW4	SW5	SW6	SW7	SW8	SW9	SW10	SW11
Mean bifurcation ratio	8	10	11	7	6	5	2	3	9	4	1
Mean steam length ratio	10	6	7	3	11	4	8	5	9	1	2
Stream frequency	2	1	4	5	11	9	6	8	10	3	7
Drainage density	2	1	6	7	11	9	4	10	8	3	5
Drainage texture	1	2	4	5	11	9	6	10	7	3	8
Length of overland flow	10	11	6	5	1	3	8	2	4	9	7
RHO coefficient	3	9	8	11	1	7	2	5	4	10	6
Drainage intensity	2	1	4	5	11	9	7	6	10	3	8
Relief	1	4	2	3	6	5	8	7	9	11	10
Relative ratio	1	3	2	4	6	5	8	7	11	9	10
Ruggedness number	1	3	2	4	6	5	8	7	11	9	10
Circulatory ratio	8	9	11	10	1	6	5	2	4	7	3
Elongation ratio	7	11	8	9	2	5	6	3	1	10	4
Form factor	7	11	8	9	2	5	6	3	1	10	4
Compactness coefficient	4	3	1	2	11	6	7	10	8	5	9
Sum of rankings (X)	67	85	84	89	97	92	91	88	106	97	94
Total number of parameters (Y)	15	15	15	15	15	15	15	15	15	15	15
Compound parameter (X/Y)	4.47	5.67	5.60	5.93	6.47	6.13	6.07	5.87	7.07	6.47	6.27
Ranking	1	3	2	5	9	7	6	4	11	10	8
Final priority	High	Medium	Medium	Medium	Low	Medium	Medium	Medium	Low	Low	Low

Correlogram of 15 morphometric parameters_

	Rbm	Rlm	Fs	Dd	Dt	Lo	p	Di	Bh	Rhp	Rn	Rc	Re	Ff	Cc
Rbm	1
Rlm	0.45	1
Fs	−0.40	0.08	1
Dd	−0.36	0.09	0.97	1
Dt	−0.54	−0.06	0.92	0.89	1
Lo	0.33	−0.13	−0.95	−0.99	−0.88	1
p	0.27	−0.72	−0.41	−0.36	−0.37	0.39	1
Di	−0.39	0.13	0.99	0.93	0.92	−0.91	−0.47	1
Bh	−0.68	−0.32	0.42	0.41	0.65	−0.40	−0.19	0.43	1
Rhp	−0.73	−0.26	0.51	0.49	0.69	−0.49	−0.29	0.51	0.98	1
Rn	−0.68	−0.33	0.52	0.50	0.73	−0.49	−0.17	0.51	0.99	0.98	1
Rc	−0.62	0.20	0.51	0.49	0.61	−0.52	−0.68	0.54	0.71	0.79	0.68	1
Re	−0.24	0.39	0.81	0.80	0.61	−0.80	−0.59	0.80	0.29	0.41	0.33	0.66	1
Ff	−0.25	0.39	0.81	0.80	0.61	−0.80	−0.59	0.80	0.29	0.41	0.33	0.66	1.00	1
Cc	0.59	−0.23	−0.56	−0.54	−0.65	0.57	0.68	−0.59	−0.69	−0.76	−0.67	−0.99	−0.69	−0.68	1

Neyyar basin linear parameters_

SW	Stream order(maximum)	Stream number(ΣNu)	Stream length(ΣLu)	Mean bifurcation ratio(Σ Rbm)	Mean stream length ratio(Σ Rlm)
SW 1	5	147	83	3.44	0.49
SW 2	5	99	51	3.07	0.62
SW 3	5	97	70	2.92	0.58
SW 4	4	74	56	3.78	0.80
SW 5	4	77	87	3.96	0.46
SW 6	4	92	77	4.11	0.77
SW 7	4	104	81	4.56	0.55
SW 8	4	102	79	4.49	0.66
SW 9	5	138	120	3.36	0.49
SW 10	4	90	54	4.24	0.86
SW 11	4	113	90	4.58	0.85

Rotated component matrix (strong coefficients are marked by the bold font)_

Parameter	Component
	1	2	3
Rbm	−0.177	−0.814	0.031
Rlm	0.084	−0.414	0.855
Fs	0.951	0.256	0.125
Dd	0.956	0.229	0.106
Dt	0.802	0.515	0.039
Lo	−0.937	−0.227	−0.148
ρ	−0.232	−0.183	−0.884
Di	0.918	0.263	0.185
Bh	0.200	0.945	−0.002
Rhp	0.277	0.937	0.087
Rn	0.311	0.911	−0.055
Rc	0.278	0.723	0.597
Re	0.752	0.139	0.544
Ff	0.758	0.149	0.533
Cc	−0.336	−0.686	−0.599

Descriptive statistics of morphometric parameters_

Parameter	N	Minimum	Maximum	Sum	Mean	Standard error	Variance	Standard deviation	Median	25 percentiles	75 percentiles	Skewness	Kurtosis
Rbm	11	2.92	4.58	42.50	3.86	0.18	0.36	0.60	3.96	3.36	4.49	−0.31	−1.33
Rlm	11	0.46	0.86	7.15	0.65	0.05	0.02	0.15	0.62	0.49	0.80	0.27	−1.61
Fs	11	1.40	4.41	28.58	2.60	0.28	0.83	0.91	2.38	1.94	3.43	0.93	0.09
Dd	11	1.58	2.27	20.27	1.84	0.07	0.06	0.24	1.83	1.62	2.06	0.61	−0.68
Dt	11	1.21	3.38	24.03	2.18	0.18	0.37	0.61	1.98	1.88	2.49	0.64	0.45
Lo	11	0.22	0.32	3.03	0.28	0.01	0.00	0.03	0.27	0.24	0.31	−0.26	−1.13
ρ	11	4.72	8.55	67.67	6.15	0.42	1.92	1.39	5.38	4.96	6.98	0.70	−0.96
Di	11	0.89	1.94	15.15	1.38	0.09	0.09	0.30	1.29	1.20	1.67	0.55	0.08
Bh	11	0.11	1.72	6.37	0.58	0.17	0.32	0.57	0.35	0.11	0.73	1.24	0.48
Rhp	11	0.18	4.17	16.46	1.50	0.46	2.32	1.52	0.64	0.34	2.46	0.99	−0.47
Rn	11	0.18	3.71	12.28	1.12	0.36	1.39	1.18	0.56	0.22	1.65	1.40	1.16
Rc	11	0.17	0.31	2.52	0.23	0.01	0.00	0.05	0.25	0.18	0.26	0.24	−1.24
Re	11	0.64	0.70	7.35	0.67	0.00	0.00	0.02	0.67	0.66	0.68	0.29	−0.11
Ff	11	0.32	0.38	3.86	0.35	0.00	0.00	0.02	0.35	0.34	0.37	0.32	−0.13
Cc	11	1.79	2.42	23.32	2.12	0.07	0.05	0.22	2.01	1.97	2.34	0.07	−1.68

Final ranking of hypsometric analysis_

Parameter	SW1	SW2	SW3	SW4	SW5	SW6	SW7	SW8	SW9	SW10	SW11
HI	0.37	0.24	0.32	0.28	0.15	0.16	0.33	0.34	0.32	0.39	0.38
Ranking	9	3	6	4	1	2	7	8	5	11	10
Final priority	High	Medium	Low	Medium	Low	Low	High	High	High	High	High

Final ranking of principal component analysis_

Parameter	SW 1	SW2	SW 3	SW4	SW 5	SW6	SW7	SW8	SW 9	SW10	SW11
Drainage density	2	1	6	7	11	9	4	10	8	3	5
RHO coefficient	3	9	8	11	1	7	2	5	4	10	6
Relief	1	4	2	3	6	5	8	7	9	11	10
Sum of rankings (X)	6	14	16	21	18	21	14	22	21	24	21
Total number of parameters (Y)	3	3	3	3	3	3	3	3	3	3	3
Compound parameter (X/Y)	2	4.67	5.33	7	6	7	4.67	7.33	7	8	7
Ranking	1	2	4	6	5	7	3	10	8	11	9
Final priority	High	Medium	Medium	Low	Low	Low	Medium	Low	Low	Low	Low

Total variance of the morphometric indices explained (15 morphometric parameters)_

Component (15 morphometric parameters)	Initial eigenvalues			Extraction sums of squared loadings			Rotation sums of squared loadings
	Total	% of variance	Cumulative (%)	Total	% of variance	Cumulative (%)	Total	% of variance	Cumulative (%)
1	9.065	60.430	60.430	9.065	60.430	60.430	5.817	38.781	38.781
2	2.921	19.471	79.902	2.921	19.471	79.902	5.007	33.382	72.164
3	1.744	11.629	91.530	1.744	11.629	91.530	2.905	19.367	91.530
4	0.521	3.471	95.001
5	0.461	3.076	98.076
6	0.165	1.100	99.176
7	0.109	0.724	99.900
8	0.011	0.074	99.974
9	0.003	0.018	99.992
10	0.001	0.008	100.000
11	2.101E-16	1.401E-15	100.000
12	8.838E-17	5.892E-16	100.000
13	2.866E-17	1.911E-16	100.000
14	−3.703E-16	−2.468E-15	100.000
15	−9.560E-16	−6.373E-15	100.000

Common priority of three methods (high = H, medium = M, low = L)_

Method	SW1	SW2	SW3	SW4	SW5	SW6	SW7	SW8	SW9	SW10	SW11
Morphometric analysis	H	M	M	M	L	M	M	M	L	L	L
PCA	H	M	M	L	L	L	M	L	L	L	L
Hypsometric analysis	H	M	L	M	L	L	H	H	H	H	H
Common priority	H	M	M	M	L	L	M	–	L	L	L