Pipe seepage?

[Rockhound2015]

I am a civil engineer (sitting for PE in October) and I am building a new house. There is a 24" HDPE stormwater pipe that runs across my lot from upstream curb inlets in the road and outlets to a detention basin behind my lot. Besides the erosion control issues, lack of outlet rock protection and other observable problems, I have not observed any water coming from the pipe, even after rain events. I have noticed water bubbling up, (like a spring) from under the endwall. (see photo)

When I showed this to the developer, he said this is "common" in low flow situations. He also noted the pipes are not sealed at the curb inlets. I asked around the office and everyone here said this is not common.

Is this common? I think there may be pipe seepage here and the beginnings of a major problem. Any help would be appreciated.

 

[Spartan5]

While we're at it, it's probably a good thing no water is coming out of that pipe as it's going to cause that temporary endwall to fall into the pond the first good bit of water that makes it out of it.

 

[Rockhound2015]

All, here a couple of pictures I took today. I should have gone yesterday right after it rained. There isn't enough water to determine anything.

Photo looking into the curb inlet. 24" pipe inlet on left, 6" curb underdrain near step.

Photo at same location, lower. Notice grouting around 24" inlet (RCP) and outlet (HDPE) pipes. This confirms the pipe is only soiltight (ADS detail 202A).

Photo looking up HDPE pipe from endwall location. This is a really small trickle, but nothing compared to the amount of water coming from under the endwall.

I will post more pictures once we have a larger rain event.

 

[beej67]

I'm a little surprised nobody's mentioned how the end wall discharges several feet above grade. If water ever does come out of that pipe, it's going to create a scour hole, undermine the foundation of the end wall, and the whole thing's going to fall over into the detention pond.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[Rockhound2015]

beej67, They are supposed to be fixing this soon, along with the erosion control issues. Not sure why it is taking so long, but they are planning to fix it...

 

[beej67]

Someone's already said this before, but I'll just hammer the point home..

..buy a lot in a different subdivision if you can. Cite poor development practices to get out of your contract if you must. I would rate the chance that this developer doesn't get litigated against to be slim to none.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com