A pipe culvert needs to be designed to carry a flow under a roadway. The allowable

clearance under this roadway will allow a $36-$inch diameter pipe.

Perform culvert analysis for barrel, inlet, outlet, and submerged outlet conditions.

Analyze culvert performance curves to determine inlet or outlet control conditions.

Data:

Location: Las Cruces, NM $($Lat $=32\mathrm{.}3917,$ Long $=-106\mathrm{.}7463)$

Drainage area: $100$ acres of residential subdivision $($C $=0\mathrm{.}5).$

Use $60-$min, $100-$year storm to calculate design flow.

Length of culvert L $=180$ ft$.$

Pipe roughness n $=0\mathrm{.}022$

Culvert slope S $=0\mathrm{.}005$

Culvert entrance: Headwall, square

H$/$D max $=1\mathrm{.}2$

Available pipe sizes: $24,36$

Find:

$($a$)$ Design flow in cfs$.$

$($b$)$ How many pipes $($of each size$)$ will be needed to carry the design flow?

$($c$)$ What is the maximum flow if the culvert operates at H$/$D $=1\mathrm{.}2$ for each pipe size?

$($d$)$ Determine whether the culvert operates under inlet or outlet control.

$($e$)$ Which pipe size would you select and why?

$($f$)$ What is the maximum rainfall intensity that the $36$ culverts can handle at H$/$D $=1\mathrm{.}2?$