Hydrology and Runoff

The optimum number of rain gauge stations $N$ required in a catchment for an allowable percentage error $p$ in mean precipitation is given by:

Options:

• (A) $N = \left(\frac{C_v}{p}\right)^2$
• (B) $N = \frac{C_v}{p}$
• (C) $N = \left(\frac{p}{C_v}\right)^2$
• (D) $N = \sqrt{\frac{C_v}{p}}$