Pipe seepage?
Pipe seepage?
(OP)
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.
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.





RE: Pipe seepage?
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Pipe seepage?
Also, don't let the water lines let you think there has been water flowing through this pipe. This pipe was reused. The developer had to tear up the new road and all underground utilities and shift the road 50' west because they didn't include a overhead utility easement in their preliminary plan design. It was a costly mistake.
RE: Pipe seepage?
RE: Pipe seepage?
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Pipe seepage?
It seems odd no water would discharge during a storm event, could there be another outfall to the system?
RE: Pipe seepage?
RE: Pipe seepage?
CarlB, There is another outlet pipe that drains another phase of the subdivision into the basin. This is the only one for this phase. There is a nice amount of water flowing from under the endwall. The lots are not graded yet to drain a lot of water to the street. The only flow to this pipe is from the street.
cvg, The cover increases further up, but I think the pipe is a little more exposed now than intended by the design (due to erosion). I didn't see any connection between the pipe and endwall either. See gap in photo?
I've asked the county engineer to look into this since it falls under their jurisdiction. I just want to make sure I don't get water in my basement because of the seepage.
RE: Pipe seepage?
If it fails further in the future, after buildings and lovely landscaping are in place, consider the impact of heavy equipment needed to repair the storm drain.
RE: Pipe seepage?
RE: Pipe seepage?
RE: Pipe seepage?
- bituminous pipe joint filler
- preformed flexible joint sealant
- or resilient and flexible gaskets
I think these are all water tight. If the pipe were for sanitary, it would need to be tested to infiltration/exfiltration.But, since they installed HDPE and used no seal (per developer), I expect the water is seeping out at the connection.
RE: Pipe seepage?
"I’m not sure who you spoke with from the development team, but when they say that the pipe isn’t “sealed”, that isn’t completely accurate. ADS N-12 pipe contains a factory installed gasket within the spigot end of the pipe to meet the requirements of 611.08. For type C conduit, we do not exclusively require RCP, despite what the drawings may say. Outside of the pavement sections, we allow HDPE pipe for storm applications, as does pretty much every other agency that I know of in Ohio and beyond. In fact, some agencies (ODOT, Delaware County and others) have approved the use of HDPE product under the roadway in a multitude of scenarios.
In terms of the water bubbling under the endwall, I wouldn’t go as far as to say this is a common occurence, but I don’t believe it’s a reason for panic. The pipe trench consists of granular backfill, and when compared with consolidated clay adjacent to the trench, groundwater will choose the path of least resistance (i.e. the trench). Being that the inlet to pond is at the most downstream end of the system, the presence of groundwater within that trench would be expected. Hope that answers your questions."
I still don't think this explains the lack of water coming from the pipe itself, but at least I have this documented now.
RE: Pipe seepage?
611.10 Drainage Structure Construction. part b
After placing the conduit, grout all openings less than 4 inches (100 mm) between the pipe
and structure with mortar. Grout all openings greater than 4 inches (100 mm) between the pipe
and structure with non-shrink mortar.
RE: Pipe seepage?
RE: Pipe seepage?
http://www.ads-pipe.com/en/product.asp?page=n_12
I think your problem is at the curb inlet where the catch basin is not connected to the pipe or another possibility is that temporary SWPPP has blocked the curb inlet to prevent sediment leaving the construction site
RE: Pipe seepage?
cvg, Thank you for this information. I think if there is a leak anywhere it will be at the curb inlet connection. I will look at this and take a photo.
RE: Pipe seepage?
Is that pipe permanent? Or was it part of a temporary sediment control basin that no longer has contributing drainage? Not that it looks like erosion and sediment control is a high priority out there.
For what it's worth, in my neck of the woods if it's in the right-of-way, it's Class IV reinforced concrete pipe with gasketed joints and someone would be getting smacked for the lack of site stabilization.
Who's responsible for operating and maintaining the pond? It's going to need to be dredged before the development is built out.
RE: Pipe seepage?
The pipe is permanent. Erosion Control is a high priority here, but it took getting the Ohio EPA involved to light a fire under this developer. I expect Erosion Control measures will be enacted this week (or fines will result).
The County Engineer let them get by with the HDPE (about 25' in ROW, rest on private property with easement) although the plans specified RCP.
Currently the Developer is responsible for the "dry" basin (not supposed to have that much water in it). Eventually, it will become responsibility of HOA. I'm hoping things get fixed before then.
I really believe there is a leak/break/etc in the piping somewhere between the curb inlet and the outlet endwall. I'm waiting until a rain event (maybe this weekend) to take pictures to confirm.
RE: Pipe seepage?
Is that an "offline" pond with a splitter structure (diverts everything above the "first flush" to a different outfall)? Oftentimes if there is a splitter structure leading to a pond or other stormwater management facility, they will require the pond feed to be blocked until the site is stabilized to prevent the facility from getting overrun with construction sediment.
RE: Pipe seepage?
RE: Pipe seepage?
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.
RE: Pipe seepage?
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Pipe seepage?
RE: Pipe seepage?
..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