Road gully trap - what's the purpose of the stopper?

[gs145]

Hi, I live on a private road and the rainwater/road gullys were blocked with leaves, so I've set about clearing them out.

Can anyone enlighten me as to what the purpose of the large stopper is as per this design:

It seems that the rainwater will already exit at the lowest point - the stopper which is above this height seems to serve no purpose?

 

[picasso]

Its to allow rodding access.

 

[oldbutnotdead]

Stopper is there to seal rod/jet access to the link pipe

 

[bernardgreen]

It provides access for drain rods when the drains need to be rodded out to clear a blockage,

 

[gs145]

Aah, I see! Thanks everyone for the replies.

 

[Malcolm Leighton]

Hi,
I am having GREAT difficulty in convincing the hoa to replace all the stoppers ,as they have been removed over the years. They must be left in to avoid detritus overflowing into the drain.
They also serve to indicate when the gully needs emptying, as the gully will overtop onto the street.
Cheers

 

[oldbutnotdead]

Their other purpose is to prevent rats using the rodding point for access to the drain runs.

 

[Dereekoo]

Their other purpose is to prevent rats using the rodding point for access to the drain runs.

Nothing to do with rats, as stated primary purpose is to open access for rodding and then bunged up to maintain integrity of water seal to prevent odours emanating from sewer system.

 

[Malcolm Leighton]

I would agree, the prime design feature is for cleaning., but it does make it more difficult for rats to enter or exit the sewer ...as an aditional feature. !
But they must be in place, where the feature is present.

 

[Hugh Jaleak]

Stopper may well be superfluous to requirements on a modern estate, where the road gullies should be connected to the Surface Water Drainage system. Only really need to seal the pots off on older streets where the gullies may be connected to a Combined system, and the rainwater was relied on to flush the sewers through in times of heavy rainfall.

 

[Dereekoo]

Stopper may well be superfluous to requirements on a modern estate, where the road gullies should be connected to the Surface Water Drainage system. Only really need to seal the pots off on older streets where the gullies may be connected to a Combined system, and the rainwater was relied on to flush the sewers through in times of heavy rainfall.

I'll think you would find that the morning "everyone up and off to work" flush would have been more than enough to flush the system except perhaps at the head of the system

 

[Hugh Jaleak]

I'll think you would find that the morning "everyone up and off to work" flush would have been more than enough to flush the system except perhaps at the head of the system

It wasn't though, hence why they directed some of the rainwater into the sewers.

 

[Malcolm Leighton]

Thanks Hugh
"Stopper may well be superfluous to requirements on a modern estate, where the road gullies should be connected to the Surface Water Drainage system."

"Only really need to seal the pots off on older streets where the gullies may be connected to a Combined system, and the rainwater was relied on to flush the sewers through in times of heavy rainfall."

Agreed..maybe..
But, ALSO, if the stoppers are not in place, then there is a danger of detritus overtopping into the link drain and causing downstream blockages.

 

[Dereekoo]

It wasn't though, hence why they directed some of the rainwater into the sewers.

They didn't direct some of the rainwater into the sewer, it was all directed in and storm overflows incorporated at strategic points in the system to send excess to rivers etc. Sewers designed to take 6DWF, normal peak flow about 2.5DWF. DWF (dry weather flow) is a flow factor based on population and average daily usage per capita (about 135litres currently I believe) In times of storm flow into sewers can be 20- 30DWF+ depending on storm intensity. At one time they would actually place an automatic dosing chamber at the head of a sewage system, a bit like a toilet cistern ( but bigger), that would discharge a cleansing flow down the system at a predetermined period although these are not in vogue anymore

 

[Hugh Jaleak]

Perhaps if the Councils/Highways emptied the Gullies a bit more often, then there wouldn't be an issue with the pipework blocking!