Inlet Question 2

[ccruse]

I have a scenario where I need to verify that a proposed inlet will operate at 100% efficiency. The inlet layout consists of 4 inlets spanned over 587ft with the greatest distance between two inlets being 184ft.

I would think that the steps I need to take in assuring the need efficiency would be as follows:
Steps
1efine Runoff (TR-55)
Look at area above (which is .00018mi^2) and determine the runoff using qP=Qu*Am*Q.
2:The area is impervious and is curbed (Type F) so calculate the discharge of the gutter. (Which Im not sure on the exact way how)
3: Look at the Inlet type being used (Curb-Opening) and determine the capacity of it. The reference I have differs from DOT specs.
4:Given all the above variables I can determine the efficiency of the inlet (E= Discharge intercepted by inlet/total discharge approaching inlet)

I think this is the steos needed to verify an inlets efficiency. I could be wrong though.

Thanks any advice is very much appreciated!!!

 

[RWF7437]

First, 100 % efficiency is NOT POSSIBLE !
Second, a drainage area of 0.00018 square miles is only 0.115 acres which is only about 5000 square feet which is probably too small to warrant the use of the TR-55 method.
Third, you have not defined any of the terms in the equation " qP=Qu*Am*Q".
Fourth, where does this equation come from and why do you think it is valid AND is applicable ?
Fifth, someone on this forum may know what a Type F curb is but most if us probably don't have any idea what you are talking about.
Sixth, the discharge capacity of a gutter may be calculated using the Manning Equation or a free program like Visual Urban ( Google it ).
Seventh,don't know what a "steos" is.

Try again.

 

[civilperson]

An inlet grate located in a sump condition, (0.6' below the gutter grade for straight line flow), is 300% to 500% greater than a straight grade flow condition inlet grate. As stated in RWF7437 posting, Mannings equation gives Q for gutter full flow. Check with grate manufacturer for flow characteristics under both flow conditions.

 

[ccruse]

Reply to RWF7437

1. Efficiency is equal to discharge intercepted by inlet by the total discharge approaching the inlet, correct? If so by theory the outlet could operate over 100%
2. If not the TR-55 what method should I use?
3. qp=Qu*Am*Q was taken from the TR-55 where:
Qu= unit peak discharge=1000 csm/in
Am= drainage area=0000183mi^2
Q= Runoff=7.06in
4. These values were determined using the TR-55 method
5. Type F curb is a type of curb defined by FDOT "Flordia Dept. Of Trans."
6. Thanks for the tip on how to calculate discharge capaciy of a gutter. I used a method that was in a reference manual I have "Stormwater Conveyance Modeling and Design, by Haestad"
7. "steos" was a type-o I meant to say "steps"

I am a recent grad that is trying to become a great engineer, so please all bear with me and I appreciate your time and help.

Thanks!!

 

[TerryScan]

ccruse,

I suggest you reference FHWA's HEC 22:

http://isddc.dot.gov/OLPFiles/FHWA/010593.pdf

Typically, the Rational Method is used to determine peak flows for highway drainage.

 

[ccruse]

Reply to TerryScan

Thanks I will look into that!! At first I considered using the rational method but another EI suggested that maybe I look into TR-55. I guess I should have stayed with my first thought..