S. No. |
Parameters |
Symbol |
Formula |
Reference |
1 |
Linear aspects |
1.1 |
Stream Order |
Sμ |
Hierarchical rank |
[19] |
1.2 |
Bifurcation Ratio |
Rb |
Rb = Nμ / Nμ +1
Where, Rb = Bifurcation ratio,
Nμ = No. of stream segments of a given order and
Nμ +1= No. of stream segments of next higher order. |
[21] |
1.3 |
Mean Bifurcation Ratio |
Rbm |
Rbm = Average of bifurcation ratios of all orders |
[19] |
1.4 |
Stream Length |
Lμ |
Length of the stream (kilometers) |
[5] |
1.5 |
Mean Stream Length |
Lsm |
Lsm = Lμ/Nμ
Where, Lμ = Total stream length of order ‘μ’
Nμ = Total no. of stream segments of order ‘μ’ |
[19] |
1.6 |
Stream Length Ratio |
RL |
RL= Lsm/Lsm-1
Where, Lsm=Mean stream length of a given order and
Lsm-1= Mean stream length of next lower order |
[5] |
1.7 |
Length of Overland Flow |
Lg |
Lg=1/2D Km
Where, D=Drainage density (Km/Km2) |
[5] |
1.8 |
Basin Perimeter |
P |
P=Outer boundary of drainage basin measured in kilometers. |
[21] |
1.9 |
Basin Length |
Lb |
Lb=1.312×A0.568 |
[21] |
2 |
Areal aspects |
2.1 |
Basin Area |
A |
Area from which water drains to a common stream and boundary determined by opposite ridges. |
[19] |
2.2 |
Drainage Density |
Dd |
Dd= Lμ/A
Where, Dd = Drainage density (Km/Km2)
Lμ = Total stream length of all orders and
A = Area of the basin (Km2). |
[24] |
2.3 |
Drainage Frequency |
Fs |
Fs = Nμ/A
Where, Fs = Drainage frequency.
Nμ = Total no. of streams of all orders and
A = Area of the basin (Km2). |
[24] |
2.4 |
Infiltration Number |
If |
If = Dd × Fs
Where, Dd = Drainage density (Km/Km2) and
Fs = Drainage frequency. |
[43] |
2.5 |
Drainage Texture |
Dt |
Dt = Nμ /P
Where, Nμ = No. of streams in a given order and P = Perimeter (Kms) |
[5, 44] |
2.6 |
Form Factor Ratio |
Rf |
Rf = A/Lb2
Where, A = Area of the basin and
Lb = (Maximum) basin length |
[24] |
2.7 |
Elongation Ratio |
Re |
Re= √A /π / Lb
Where, A= Area of the basin (Km2)
Lb=(Maximum) Basin length (Km) |
[21] |
2.8 |
Circularity Ratio |
Rc |
Rc = 4πA/ P2
Where, A = Basin area (Km2) and
P= Perimeter of the basin (Km) |
[40] |
3.0 |
Relief Aspects |
3.1 |
Basin Relief |
H |
H = Z – z
Where, Z = Maximum elevation of the basin (m) and
z = Minimum elevation of the basin (m) |
[45] |
3.2 |
Relief Ratio |
Rr |
Rr = H/Lb
Where, H = basin relief (m) and
Lb = Basin length (m) |
[21] |
3.3 |
Dissection Index |
DI |
DI = H / Ra
Where, H = basin relief (m) and
Ra = Absolute relief (m) |
[46] |
3.4 |
Channel Gradient |
Cg |
Cg = H / {(π/2) × Clp}
Where, H = basin relief (m) and
Clp= Longest Dimension Parallel to the
Principal Drainage Line (Kms) =Lb |
[47] |
3.5 |
Basin Slope |
Sb |
Sw = H / Lb
Where H and Lb= given above |
[42] |