Morphometric parameters

Formula/Definition

References

I. Drainage network

1. Stream order (u)

Hierarchical rank

[8]

2. No. of streams (Nu)

[6]

3. Stream length (Lu) km

(km)

[9]

4. Mean stream length (Lsm) km

Lsm = Lu/Nu (km)

[9]

5. Stream length ratio (R)

RL = Lu/Lu − 1, where Lu = the total stream length of order “u”, Lu − 1 = the total stream length of its next lower order.

[6]

6. Bifurcation ratio (Rb)

Rb = Nu/Nu + 1, where Nu = total no. of tream segment of order “u”, Nu + 1 = no. of segments of the next higher order.

[40]

7. Mean bifurcation ratio (Rbm)

Rbm = average of bifurcation ratio of Strahler all orders.

[8]

II. Basin geometry

8. Basin length (Lb) km

Length of the basin (km)

[6]

9. Basin area (A) km2

Plan area of the watershed (km2)

[6]

10. Mean basin width (Wb)

Wb = A/L

[41]

11. Basin perimeter (P) km

Perimeter of the watershed (km)

[6]

12. Form factor (ratio) (Rf)

Rf = A/Lb2

[6]

13. Elongation ratio (Re)

Re =

[40]

14. Compactness coefficient (Cc)

Cc = 0.2841 * P/A0.5

[42]

15. Texture ratio (Tr)

Tr = N1/P

[40]

16. Shape index (Bs)

Bs = Lb2/A

[6]

17. Lemniscate ratio (k)

k = L2/4A

[43] [44]

18. Circularity ratio (Rc)

Rc =

[9] [39]

19. Drainage texture (Dt)

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

[6]

III. Drainage texture analysis

20. Stream frequency (Fs)

Fs = Nu/A

[6]

21. Drainage density (Dd) km/km2

Dd = Lu/A

[6]

22. Drainage intensity (Di)

Di = Fs/Dd

[45]

23. Constant channel maintenance (C) km2/km

C = 1/Dd

[40]

24. Length of overland flow (Lo) km

Lo = 1/2Dd

[6]

IV. Relief characteristics

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

Bh = h − h1, where,

h = maximum height (m)

h1 = minimum height (m)

[46]

26. Relief ratio (Rr)

Rr = H/Lb, Where

H = total relief

Lb = basin length

[9]

27. Ruggedness number (Rn)

Rn = Dd * (Bh/1000)

[9]

28. Dissection index (Dis)

Dis = Bh/Ra, where Ra = absolute relief

[47]

29. Time of concentration (Tc)

Tc = 6.95 (L1.15/Bs0.385)

[48]

where L = length of main stream