Bunds are to be constructed to conserve rainwater in a farm having $6 \%$ slope. If the horizontal interval between two bunds is $30 \mathrm{~m}$ and there is no loss of water, the required height of the bund to store rainwater from an $18 \mathrm{~cm}$ rainfall event with 10 years of return period in $\mathrm{cm}$ will be______________
Bunds are to be constructed to conserve rainwater in a farm having $6 \%$ slope. If the horizontal interval between two bunds is $30 \mathrm{~m}$ and there is no loss of water, the required height of the bund to store rainwater from an $18 \mathrm{~cm}$ rainfall event with 10 years of return period in $\mathrm{cm}$ will be______________