HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
(OP)
hello everyone,
I'm fairly new to the detention pond hydraulics concept but am understanding it so far. A question or two....I've read in some manuals (don't recall specific ones)or books that the user should calculate the weir and orifice equations. Is this for a riser pipe (or box) or is this for the horizontal pipe that would be considered the principal spillway (without riser)? Because the detention pond has both structures (principal and emergency spillways), can I use HEC-HMS to calculate the flow through the detention pond?
Oh, another question...I've also seen a 1' dimension from the emergency spillway. When I put in the elevation for the emergency spillway, do I put in the elevation at this 1' below emergency spillway or do I put in the actual elevation of the emergency spillway?
Thank you!!
I'm fairly new to the detention pond hydraulics concept but am understanding it so far. A question or two....I've read in some manuals (don't recall specific ones)or books that the user should calculate the weir and orifice equations. Is this for a riser pipe (or box) or is this for the horizontal pipe that would be considered the principal spillway (without riser)? Because the detention pond has both structures (principal and emergency spillways), can I use HEC-HMS to calculate the flow through the detention pond?
Oh, another question...I've also seen a 1' dimension from the emergency spillway. When I put in the elevation for the emergency spillway, do I put in the elevation at this 1' below emergency spillway or do I put in the actual elevation of the emergency spillway?
Thank you!!





RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
I must be making this way too hard, as I normally do. LOL
Thanks again!
BillsSis
RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
I would think HMS does this, but the last time I worked in HMS I found it to be a little clunky, so using another software as a check vs its rating curve might be a pretty good idea.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
Thanks for both of your thoughts. The culvert is a 2.5' diameter HDPE pipe at a 4.5% slope from inlet to outlet. So, in anticipation of the results, I would think this structure's headwater would be greatest using the orifice equation. I will use the HY-8 program to give me a good idea of what I'm looking at, then use the HMS program.
thanks again! here goes nothing....
RE: HDPE pipe as principal spillway with 10' wide weir (3:1 side slopes) as emergency spillway
as far as the 1 foot below the emergency spillway, I assume that you want 1 foot of freeboard above the design water surface elevation before water begins to flow over it. Usually these are designed to handle flows larger than 100-year storm runoff.