NB: For each problem, show detailed calculation steps for determining the flow for each pipe section.

Problem# $1$

A storm sewer system for a watershed consists of four areas A$,$ B$,$ C and D as given in Figure $1.$ The direction of flow from each area and between the manholes is given by an arrow. Using rational method, determine the $25-$year peak flow for each sewer section. The IDF given in Figure $2($Page $2)$ reflects the intensityduration$-$frequency relationships for the watershed. Assume the time travel between each manhole is $5$ minutes.

Main sewer collector

Figure $1$

Table $1$

$\backslash$table$[[$Drainage Area,Arae $($acres$),$Coefficient of runoff, C$,$Overland flow time $($minutes$)],[$A$,5,0\mathrm{.}6,8\mathrm{.}0],[$B$,5\mathrm{.}4,0\mathrm{.}7,9\mathrm{.}2],[$C$,2\mathrm{.}5,0\mathrm{.}7,7],[$D$,6\mathrm{.}5,0\mathrm{.}5,14\mathrm{.}5]]$

Problem # $2$

Table $2$