Morphometric parameters

Formula/Definition

References

I. Drainage network

1. Stream order (u)

Hierarchical rank

[8]

2. No. of streams (N_u)

[6]

3. Stream length (L_u) km

(km)

[9]

4. Mean stream length (L_sm) km

L_sm = L_u/N_u (km)

[9]

5. Stream length ratio (R)

R_L = L_u/L_{u − 1}, where L_u = the total stream length of order “u”, L_{u − 1} = the total stream length of its next lower order.

[6]

6. Bifurcation ratio (R_b)

R_b = N_u/N_{u + 1}, where N_u = total no. of tream segment of order “u”, N_{u + 1} = no. of segments of the next higher order.

[40]

7. Mean bifurcation ratio (R_bm)

R_bm = average of bifurcation ratio of Strahler all orders.

[8]

II. Basin geometry

8. Basin length (L_b) km

Length of the basin (km)

[6]

9. Basin area (A) km²

Plan area of the watershed (km²)

[6]

10. Mean basin width (W_b)

W_b = A/L

[41]

11. Basin perimeter (P) km

Perimeter of the watershed (km)

[6]

12. Form factor (ratio) (R_f)

R_f = A/L_b²

[6]

13. Elongation ratio (R_e)

R_e =

[40]

14. Compactness coefficient (C_c)

C_c = 0.2841 * P/A^0.5

[42]

15. Texture ratio (T_r)

Tr = N₁/P

[40]

16. Shape index (B_s)

Bs = L_b²/A

[6]

17. Lemniscate ratio (k)

k = L²/4A

[43] [44]

18. Circularity ratio (R_c)

R_c =

[9] [39]

19. Drainage texture (D_t)

Dt = N_u/P, where Nu = Total no. of streams ofall orders, P = perimeter (k)

[6]

III. Drainage texture analysis

20. Stream frequency (F_s)

F_s = N_u/A

[6]

21. Drainage density (D_d) km/km²

D_d = L_u/A

[6]

22. Drainage intensity (D_i)

D_i = F_s/D_d

[45]

23. Constant channel maintenance (C) km²/km

C = 1/D_d

[40]

24. Length of overland flow (L_o) km

L_o = 1/2D_d

[6]

IV. Relief characteristics

25. Basin relief (B_h) or total relief (H) m

B_h = h − h₁, where,

h = maximum height (m)

h₁ = minimum height (m)

[46]

26. Relief ratio (R_r)

R_r = H/L_b, Where

H = total relief

L_b = basin length

[9]

27. Ruggedness number (R_n)

R_n = D_d * (B_h/1000)

[9]

28. Dissection index (D_is)

D_is = B_h/R_a, where R_a = absolute relief

[47]

29. Time of concentration (T_c)

T_c = 6.95 (L^1.15/B_s^0.385)

[48]

where L = length of main stream