UnidentifiedMethods ADR$($mm$)=\backslash$Sigma $($A$\_\{$i$\}*$P$\_\{$i$\}/\backslash$Sigma $\backslash$Alpha $\_\{$i$\}$ Where A$,$ is the polygon area $($km$^3),$ P$\_\{$i$\}$is the rainfall $($mm$)$ corresponding to the i polygon, and $\backslash$Sigma A$\_\{$i$\}$ is the catchment area $($km$^2).$ Isohyetal Method The average depth of rainfall over the entire catchment can be calculated using: ADR$($mm$)==\backslash$Sigma $($A$\_\{$i$\}*$P$\_\{$i$\}/\backslash$Sigma $\backslash$Alpha $\_\{$i$\}4,$ is the total catchment area where in this method A$,$ is the area between isohyets P$\{$i$\}$ and P$\{$i$+1\}($km$^2),$ P$\_\{$i$\}$ is the average rainfall $)$ corresponding to the area A$,$ between the isohyets, and $\backslash$Sigma $\backslash$Alpha $\{$i$\}$ is the total catchment area $($km$^2).$ Activity