Practice Problem #2

[John QPE]

A 6ft x 5ft square-edged concrete box culvert with 0* wingwall under a roadway crossing passes 300 cfs.

Shoulder elevation = 114 ft

Invert = 100 ft

Slope = 0.02 ft/ft

TW Depth = 4 ft

Length of culvert = 250 ft

Max Allowable HW elevation = 109 ft

Ke = 0.5

n = 0.012

Does the culvert meet the maximum allowable HW depth for this crossing? What is the HW depth?

If a flash flood occurs, and 500 cfs reaches the culvert, will the flow overtop the road?

 

[ptatohed]

Come on people, it's Exam month.....

 

[bradlelf]

Wait ... I do not understand. Are we waiting for a test taker to solve the problem as practice or does someone legitimately need help? I can provide help if the latter.

 

[ptatohed]

Wait ... I do not understand. Are we waiting for a test taker to solve the problem as practice or does someone legitimately need help? I can provide help if the latter.

These "quizzes" and "practice probs" have been posted in the this Transpo forum by JQ and me to provide those who are studying with additional practice.

 

[zzzvvvzzz]

Yes it meets.

HW=8.25

No

HW=16.25 @ 500cfs overtop by 2.25ft

 

[John QPE]

It's been so long I need to work this problem again. I'll get back to you.

 

[dcald86]

Bump

Scanning thru the old pratice problems,  possible to get a worked out solution to this?

 

[John QPE]

I need to look around. most likely I need to rework this problem. 

 

[ptatohed]

I'm no water guy so I probably messed up somewhere.  For 300 CFS, I get Hydraulic Head, H = 3.03 feet.  The tailwater is 95 + 4 = 99.  Add H to the tailwater, headwater = 99 + 3 = 102.  102 < 109: ok.

For 500 CFS, H = 8.43'.  HW = 99 + 8.4 = 107.4.  107.4 < 114: ok.

How badly did I screw up?