Garden drainage HELP! Please.

designmike

We bought our home a few years ago and part of the garden has terrible drainage issues with rain water taking ages to disappear from a few areas. The problems are mainly due to the clay soil and the fact that the garden is lower than the road.

The area in question is currently a top layer of bark chipping with a mixture of what looks like MOT underneath, then a weed fabric, then the soil.

The two main areas that the water collects are marked in the photo above.

yesterday I decided to dig a hole in each area about 2ft deep. The left area seems to be very dense soil at this depth and the right is very very very thick dense clay soil.



I filled the holes with water to see how they drained... they didn’t. Two hours later nothing had happened. 

Unfortunately  overnight it it rained and the holes now look like this ...



I’m stuck as to what to do to drain this water to a suitable place!? Can anybody help at all, all advice is greatly appreciated as I’m desperate to get this sorted ASAP.

Thank you.

stuart.dot

I think the d-i-y course of action might be to dig a series of soakaways. If you buy a post hole auger (£20 ish), you can bore neat 6" diameter holes to a depth of 2-3 feet and fill with gravel. There are probably more sophisticated options involving pumps etc

designmike

Thanks Stuart but I don’t think soakaways are an option due to the clay soil going so deep and being so dense. I imagine they will just fill up and overflow rather quickly. Plus the problem areas are only a few metres away from the house and right next to the patio so not really ideal especially when the house has been through some subsidence/settlement in the past?

stuart.dot

Well you can't change the water table but, if you have a dozen holes, each holding 50 ltrs, It would have to rain a lot more before it sits on the surface. Everything will flood eventually if the rainfall is persistent enough. All relative ennit

Sussexsun

I had a similar problem on my shingle driveway. Whilst I was having my new permeable block paved drive way put in last year I had a soakaway  put in. 6 ft deep by 6 ft by 6 ft.
i am on heavy clay which has been compacted by years of driveway use and it cured the problem.

Lizzie27

Hi  Design Mike,  I agree with Sussex Sun and Stuart. We had a large soakaway put in under our parking area when we disturbed a natural spring whilst having a new garage built and it solved the problem. What were you thinking of using the area for and does the water still appear in the summer? 

designmike

Thanks for the feedback everyone. The area willl be used for the children to play on, may even put some Astro down or keep the bark. 

Im looking online now to research the soakaway a bit more.

I’ve had another thought. In the photos you can see I removed the manhole cover on the patio. This is the inspection chamber for our soil pipe, which as far as I am aware(need to check) also takes the surface water from the smaller drains on the patio. What do you think about me creating a couple of surface drains on the bark area and breaking through the side of the chamber and directing the water into there?

stuart.dot

Sharp intake of breath there! No idea

BobTheGardener

Pour a bucket of water down one of your patio drains.  If you can see it flow in the manhole, you have a "combined" sewer and, as a last resort, can be used.  If it doesn't your manhole is covering a foul water only sewer and you should not discharge surface water into it.
See here.

Lizzie27

If you are thinking of doing anything like that, I think you need to get professional advice.  Your latest photo shows more clearly that the ground slopes towards the patio and therefore the water will always be a problem.

Sussexsun

I think messing with your drains is a more complicated method of trying to deal with your problem when a decent sized soak away dug in the middle of your gravel area would solve the problem.