Water flooding next door's driveway / borehole?

Water flooding next door's driveway / borehole?

Author
Discussion

AstonZagato

Original Poster:

12,652 posts

209 months

Saturday 12th April 2014
quotequote all
A weird one.

My neighbour phoned me to say that water was flooding part of their driveway - about 3m square to a max depth of 4cm. It happens periodically (and relatively suddenly - there one day, gone a few days later only to return after a few hours) - apparently nothing to do with rainfall

I wandered around to see what it looked like. There is a very wet patch, that seems to start from my boundary wall and their gravel drive dips a bit - it is a the dip that fills with water. There is some green slime in the wet bit, so it has been there a while.

Now the odd thing is that there is nothing close by that would have periodic water flow. The sewerage pipes are a good 20m away and the source of their flooding is 5m from the house (the wall is the wall of a walled garden). The closest source of water is a borehole that we do not use with any sort of regularity - it is capped but the cap leaks (water settles to about 3 foot below the surface and their driveway). It has a pump in the manhole in which it sits and we occasionally use the leaking water to fill our rainwater tank (underground and another 5m further from the boundary). The borehole was not put in by us or the previous owner - it looks maybe Victorian but uncertain (it isn't on the British Geological Survey). The borehole is permanently covered so it will take some digging to take a look inside

There is a mains-fed tap further down the wall but I have no idea where the pipe runs - presumably along the wall underground.

On their side of the wall are leylandii. It is very difficult to see what is happening at the foot of the wall (pressure seems high on the tap).

On our side, there is no sign (without doing any digging - haven't got there yet) of water flowing in their direction.

So, I guess my questions are:

1. What would cause periodic floods that have (allegedly) no obvious link to rainfall?
2. Could it be coming from the pipework for the tap? If so, why periodic flooding?
3. Could the borehole "surge" many days after rain
4. Anyone know somebody who knows what to do with disused boreholes?
5. What steps can I take to find the source without wrecking my garden?
6. Given that currently there seems to be no link, is it my liability?

ikarl

3,730 posts

198 months

Saturday 12th April 2014
quotequote all
Any pics?

AstonZagato

Original Poster:

12,652 posts

209 months

Saturday 12th April 2014
quotequote all
Nothing to take pics of other than the garden - nothing to see on my side without digging. Might do it tomorrow.

Neighbour had some pics of the flooding. I might see if she will email them to me.

AstonZagato

Original Poster:

12,652 posts

209 months

Sunday 13th April 2014
quotequote all
So this is the flooding in the neighbour's drive (note the green slime indicating that it has been a problem for a while):


This is the view from my terrace towards the flooding (it's probably about in line with the stone urn, the other side of the wall)


The borehole is in a manhole under the slate chippings (close to the terrace, to the left of the terracotta urn). Slate chippings bone dry:


The earth on the far side of the slate chippings - dry as any of the rest of the garden:


AstonZagato

Original Poster:

12,652 posts

209 months

Sunday 13th April 2014
quotequote all
To find out what is happening in the manhole, I need to clear the chippings and cut into the weed membrane.

Chrisgr31

13,440 posts

254 months

Sunday 13th April 2014
quotequote all
The borehole might fill up with water a few days after the rain but that depends on whether you are in a dip with higher ground around I would have thought.

I suggest keeping details of the weather, ie what days and time does it rain and asking the neighbour to keep records of the flooding. You'll then be able to see if the flooding occurs at a fixed time after the rain.

cptsideways

13,535 posts

251 months

Sunday 13th April 2014
quotequote all
Your borehole is more likely to be a natural spring which is now topped off

AstonZagato

Original Poster:

12,652 posts

209 months

Sunday 13th April 2014
quotequote all
I had already asked them to keep records so we can see if there is a link to rainfall. I suspect there will be.

AstonZagato

Original Poster:

12,652 posts

209 months

Wednesday 16th April 2014
quotequote all
First new flood was yesterday.

Our side bone dry.

No rainfall since last flood.

Chrisgr31

13,440 posts

254 months

Wednesday 16th April 2014
quotequote all
Wonder whether there is a land drain running down the boundaries between your properties which is where the water is coming from? Could be caused by someone somewhere watering.

So whats at the end of your properties probably the higher end!

greygoose

8,224 posts

194 months

Wednesday 16th April 2014
quotequote all
Neighbour had a similar puddle appear and it was a broken water pipe into their house, do you have any plans to show where the water pipes are? Their puddle was constantly there though whereas yours seems to come and go which seems odd.

AstonZagato

Original Poster:

12,652 posts

209 months

Wednesday 16th April 2014
quotequote all
The next property on the higher side of the house is about 150m away (however, we are talking Cambridgeshire so "higher" is very marginal). It has a lake but that is not high.

There is my swimming pool that is higher but the level seems fine on that and the soakaway for the backwash is probably 30m away (and the other side of the neighbour's house.

rovermorris999

5,195 posts

188 months

Wednesday 16th April 2014
quotequote all
You could get the water tested for salts which should tell you if it's ground water or not.

Chrisgr31

13,440 posts

254 months

Wednesday 16th April 2014
quotequote all
rovermorris999 said:
You could get the water tested for salts which should tell you if it's ground water or not.
I was going to suggest this as well.