Waterlogged clay soil lawn, drilled sump holes...

[garmcqui]

Hi, long story short - newbuild house in 2014, due to compacted heavy clay soil, during the past 3 winters the bottom half of garden has become very very boggy, lots of moss growing and lawn is unusable.

Have tried hollow tine aeration, top dressing with sand etc, with little difference. So decided I would dig a few drainage sumps using an 8” Petrol driven auger, with the plan being to fill them with stones, then top off with topsoil and seed.

However, I’ve drilled three holes, each about 18” deep. The clay was very heavy, even stopping the auger turning on full throttle several times. To test what the drainage was like, I emptied a gallon of water into each hole yesterday evening, and was dismayed to see how slowly they drained (if it all). I have also tried poking down another 12-18” in the bottom of each hole with a demolition crowbar, just to see if I could get some of the water to drain - no joy.

So, filling with stones/sand is unlikely to help the waterlogging if the ground is this impermeable unless I get through the clay (or whatever’s underneath).

Photo below was taken this morning ~14hrs after piloting a gallon in each hole

So what next? Any advice appreciated

[surveyor]

French drain maybe?

[Mr Pointy]

Have a look at this thread, although his problem was a layer of concrete. Look at the sort of drainage he put in.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Capt Bravz]

It'll take some large frozen sausages to fill those holes!!

[Pheo]

Did you go down far enough? PavingExpert recommends 1.7m (!) for testing for soakaway as it may take that much to get through the top layer of clay....

On Weald clay here so feel your pain.

[LeadFarmer]

Soakaways in clay soil just become ponds. With nowhere for the water to go to it just fills up and sits there.

[Andy 308GTB]

LeadFarmer said:

Soakaways in clay soil just become ponds. With nowhere for the water to go to it just fills up and sits there.

This.

When I had an extension on my house, the rainwater had to be routed to a soak away in the garden. The builder dug out a 1m X 1m hole which was at least 2m deep, probably 3m because I can remember the guy digging it wasn't visible!
The first time we had heavy rain, the water backed up and flooded the patio and garden. Shortly afterwards I routed the rainwater into the normal drain.