Question

What will be the form factor for a drainage basin having the following data: Area of the basin = $3000 \, \text{km}^2$; Length of the main stream = $100 \, \text{km}$, and Perimeter of the basin = $300 \, \text{km}$?

• A. 0.1
• B. 0.3
• C. 1
• D. 0.05

Hint:

For form factor calculations, always ensure the area and length units are consistent. A lower form factor indicates an elongated basin.

Answer 1

The Correct Option is B

The form factor ($F_f$) of a drainage basin is calculated using the formula:
\[F_f = \frac{A}{L^2}\]
where:
$A = 3000 \, \text{km}^2$ (area of the basin),
$L = 100 \, \text{km}$ (length of the main stream).
Substitute the values:
\[F_f = \frac{3000}{100^2} = \frac{3000}{10000} = 0.3\]