Newbie with possible culvert issues

[Pete T]

Hello all,

 

My wife and I live in an early '70s timber-framed house and we are mulling over a timber-frame extension. We live in a semi-detached house with our north wall connecting us to our neighbours. The house was built with a garage joined on to the south side of the property (it's on the right as you look at the front of the house). We'd like to extend over the top of the garage; however, the width of the garage alone would not give us a sensible sized bedroom upstairs. Because of this, we'd like to extend a little further south, but this is where it gets interesting...

 

Between us and the neighbouring (mirrored) property to our south, is a culvert that was built to direct a stream that existed prior to the housing estate being built. It's not clear from any plans that I have seen, exactly where this culvert is, or how large it is. It is always drawn as a single line threading between houses and through gardens. It appears to be in my neighbours garden at the far rear of the properties, but soon crosses the boundary into our garden and will, I suspect, cause some planning issues.

 

I'm hoping that somebody on this forum may be able to provide some advice on how to proceed? The plans seem to imply that the local water company are not responsible for the culvert, which leaves me wondering "who is?" Before we start throwing money at the wrong people, who do we need to take a look at this and assess the situation? An architect? A surveyor? Somebody else? Any advice on where to start would be gratefully received.

 

Pete

 

[ProDave]

I think the only way you will identify it for sure is to dig to look for it.  I would start by digging at the front corner of the garage in the direction the extension would go, dig about a metre down and dig as far as you would want to extend.  If you don't find it, then don't mention it?

 

As to who is responsible?  Probably you.  I believe this would make you a riparian owner, just like I am with a burn running through my garden.  Covering the entire burn would not make it go away.

 

To make alterations if for instance you did find it and would have to move it over or build over it, I suspect it would be the Environment Agency assuming you are in England.

 

One final thought do you know anyone good at dowsing?  A set of divining rods might enable you to locate it.

[Rmawdsley]

Where does the culvert run? is there an outlet further down the line?

[Pete T]

10 minutes ago, Rmawdsley said:

Where does the culvert run? is there an outlet further down the line?

 

 

I probably didn't do it justice with my description. This culvert runs from the edge of town into the centre of town, where it meets with the local river. They basically enclosed a running stream. I presume this culvert has grown with the town as the town expanded further from the river.

[PeterW]

Interesting one this - have you got any indication that water actually flows down it ..? Is it only a storm drain type set up..?
 

If you own the culvert then you can move it if it’s on your land, unless it’s owned by a drainage board (so you would need to be in Lincolnshire/Norfolk/Cambridgeshire) at which point they need to be kept in the approval process. 
 

If it is dry at certain times then it isn’t classed as a watercourse per se, but you would need to ensure it is kept clear or free from sharp bends etc. 
 

A timber frame extension also gives you the option of lightweight foundations such as screw piles so you can avoid the culvert altogether but I wouldn’t want to be having it under my floor ..!!

[Rmawdsley]

If it is piped then you may be able to look for an access point/manhole cover somewhere close to your house. It would most likely be in the road/footpath or on public property. If you are successful, ring up a drainage jetter and get them to trace it to your property. If you cant find a manhole cover or any access, get digging like Dave said. If you get to virgin clay at any depth you know its not there. If it looks to be back fill, you will need to investigate further.

[ProDave]

How old is the house? Any chance of contacting the original builders for more info like how deep and what it is encased in?

[Temp]

Ownership and more..

https://www.gov.uk/guidance/owning-a-watercourse

 

Suggests you need to contact your "lead local flood authority" (which is usually your council) or "internal drainage board" (eg in the Fens).

 

[Pete T]

Thank you all for your responses. You've given us some good pointers on where to start.

[Pete T]

I only just realised that I never followed up on this. Apologies that this response is 4 years late, but I thought I would update this just in case anybody in the future finds themselves in this very specific situation!

 

We determined that the culvert is classed as a "main river", meaning that (as far as we can tell) we are the riparian owners as @ProDave pointed out earlier. The classification also means that a permit from the Environment Agency needs to be obtained (in England) before carrying out any work near the "river". We liaised with the Environment Agency (who were very helpful and pragmatic) to determine what could, and could not, be done. However, a change in circumstances led us to put our plans on pause.