What sort of drainage survey do I need?

[kent_phil]

Bit of an unusual one here - we have an un-adopted road which has had a road association managing it for many years very successfully.

One of the activities the road association undertakes is getting the gutters vacc'ed out twice a year so the surface water all drains without issue.

The torrential rain this year has caused new problems not seen before with the gutter entries to the drainage system being overloaded in the direct rain and then taking ages to clear the water afterwards.

It looks like we need to get the gutters vacc'ed out more frequently but this will only solve half of the problem.

South West Water have been out along with a couple of drainage companies and everyone has a different opinion on what needs to be done to solve the problem.

It is highly likely the problem is the connection with the main village sewer that runs down the hill in the village but no idea what we can do about this, other than let's get a professional opinion on what can be done and what is not worth doing.

Can anyone help with what sort of survey type I need to be looking for to get this advice?

Many thanks in advance - Phil

[Mr_J]

It sounds like an issue with the carrier drain that connects the gullies to the outfall, it could be blocked, collapsed, damaged by tree roots etc.

My first port of all would be a CCTV survey. That should highlight if there's an issue with the actual carrier drain itself.

[kent_phil]

Thanks for this - I'm picking it up mid-way through so don't have the full history.

South West Water came out and did a full video survey a couple of months ago - they found some fibrous roots in the main drain so put a flail down to clear them, otherwise gave it a clean bill of health. Hasn't made any difference.

Another drain company recommended increasing the size of the carrier drain (thanks Mr_J for the terminology) but South West Water said it was fine.

With the weather patterns shifting it feels like we can't ignore this, the water is overflowing the kerbstones into peoples properties, and will only get worse.

[kent_phil]

Mr_J said:

It sounds like an issue with the carrier drain that connects the gullies to the outfall, it could be blocked, collapsed, damaged by tree roots etc.

My first port of all would be a CCTV survey. That should highlight if there's an issue with the actual carrier drain itself.

Mr_J - thanks for the pointers on the correct terminology, was enough to fine tune the google searches and understand how it all works.

Result was that I did my best James Herriot impression and stuck my arm down the drains - all completely silted up way above the connection point to the carrier drain. Cleared them out which has cleared the pooling water and is easily keeping on top of the downpours that have blown through today.

So just need to keep on top of clearing the silt regularly and see how it goes this year. Definitely more mud on the roads from the local fields with the amount of rain, I suspect this is what is causing the drains to silt up quicker.

Thanks,

Phil

[hidetheelephants]

How the hell did SWW's camera survey miss that? Half a job. The unadopted lane beside my hovel has a similar drain infarction but no commensurate functioning road association. Not looking forward to investigating it but if I don't no bugger else will.

Edited by hidetheelephants on Thursday 4th April 20:16

[miko382]

Late to this but leaving it for anyone with the same issue. Had a similar situation on an unadopted road - surface water backing up after heavy rain, gutter entries overwhelmed, suspected connection issue with the main sewer further down.

Three different companies came out and gave three completely different opinions. Used Tower Surveys Associates for a CCTV drainage survey and topographical assessment combined. The CCTV found a partial blockage at the sewer junction that nobody had identified just by looking. Took the report to the water authority and the conversation changed immediately.