The state stormwater regs specify that geotextile must meet "federal department of transportation requirements for a Class 'C' filter fabric" beneath rip rap and as an interface between layers in infiltration treches. Where can I find the specs for a "Class C" fabric?
From the Rhode Island Soil Erosion and Sediment Control Handbook:
Equation #1: for low density residential development (lot size greater than 1/4 acre). SV = [(76.6 x RA x TE) + (4.0 x DA x TE)] x T
Equation #2: for high density residential development (lot size less than or equal to 1/4 acre...
HydroCAD is the best in my book. Not only does it offer great functionality and is easy to use, it is based on TR-20 and TR-55. This is essential for permitting around here. The documentation and technical support is outstanding as well.
The Time of Concentration is often described as the time for water to travel from the "most hydraulically distant point". My Civil Engineering Reference Manual adds "timewise" to this definition.
What is the general consensus out there? Do you use the path that gives the longest Time of...
Here are a couple of more references:
http://www.michigan.gov/deq/0,1607,7-135-3313_44117-163660--,00.html
also, go here: http://nepis.epa.gov/Exe/ZyNET.EXE?ZyActionL=Register&User=anonymous&Password=anonymous&Client=EPA&Init=1 and search for 625r92005
Good luck
Dickon17 - thank you, thank you, thank you for the explanation. Putting it that way clears it up for me after all these years! Once the flow is in the pipe the flow rate is constant. However, the head loss in the pipe restricts how much flow can ENTER the pipe to begin with.
mbeychok -...
I understand the difference and relationship between flow rate and velocity. I know that if the flow rate is constant then velocity increases with a decrease in area.
So then how is it that an orifice restricts the flow rate? Wouldn't the velocity increase hence maintaining the flow rate...
Thanks for all of your help. I have 2 more questions if you don't mind.
1) Perhaps you can explain something to me that I can't seem to wrap my mind around. It seems common sense that a small hole in an orifice plate will limit the flow through a pipe system. However, the continuity equation...
Excuse this dumb question from a civil engineer but this scenerio you describe has long perplexed me. I am more comfortable working with open channel flow. Perhaps you can explain this to me.
If I understand correctly, the 20" pipe has been chosen to increase the flow rate. Why wouldn't the...
It looks like that is a derivation of the equation for flow from a tank: Q=C x A x root (2 x g x h) That was what I had planned to use but I wasn't sure if it was appropriate for this application. Thanks for the confirmation I appreciate it.
You are right. My original design did restrict the flow with the friction loss of the pipe length. The owner has asked for an orifice plate for maintenance reasons though.
I can't use a valve for this application either. The restriction needs to be "hard wired" so to speak. I can't take the...
I have designed an underground flow diffuser to recieve bleed off water from a cooling tower. I must restrict the flow of water to the diffuser to less than about 3 gallons per minute. I want to use an orifice plate to do this.
The bleed line is tied into a pressurized pipe. The pressure at...
