HDPE corrugated/profile vs RCP

[SMIAH]

I am reviewing a detention basin (low earth-dam) proposed with HDPE corrugated pipe as the evacuation system.
It will have to work with max 4 ft of water over the top of the pipe.

We normaly accept these with an RCP pipe and I say that corrugated HDPE is not a equivalent to RCP.

But what if they propose a profile HDPE pipe (e.g. Weholite)?

 

[cvg]

there are pros and cons to each type of pipe, but this seems to be a very small embankment and either could work. what is bothering you about HDPE (corrugated or profile wall)?

 

[SMIAH]

HDPE corrugated issues would be long term deflexion, fact that it was to work with an head upstream, piping, there were no anti-seep collars so issue there aswell.

 

[cvg]

agree that RCP is not equal to corrugated HDPE but that does not mean that for a low embankment, flexible pipe couldn't work. kind of depends on the risk you want to accept and design life you want.

seepage collars really are old technology, rarely used anymore. you should be using a filter diaphragm instead.

upstream head of 4 feet may require leak proof joints instead of typical soil tight joints if you are concerned with that. although for a detention basin, isn't the 4 foot of head only a transient situation? whats your drain time? typically we use 36 hours for detention basins.

flexible pipe will flex whether it is CMP, HDPE corrugated, profile wall, steel reinforced poly pipe, PVC, or any other type of flexible pipe. pipe may be encased to limit flexure and this is common on larger dams.

 

[SMIAH]

Thanks cvg.