A separate sewerage system has to be designed for a suburb near Delhi for a rainfall frequency of $2$ years. This town is already provided with adequate water supply from water$-$works at per capita rate of $2001/$day$/$person$.$ Compute the maximum storm drainage discharge for which the S$.$W$.$ drain, of a pocket draining an area of $20$ hectares will be designed. Also compute the peak design discharge for which the sewers of this pocket will be designed. Make use of hourly rainfall charts and assume the concentration time $($or inlet time$)$ as $20$ minutes. The population of the pocket discharging sewage is $9000.$ Make suitable assumptions.