Garden Flooding

Dannymole22

Hi All,

My back garden is sloped away from the house and when we get rainfall like we've had in the last few days the end of my garden holds a lot of water (enough to reach about 1/3 of the way back toward the house.)

The slope is quite pronounced and with my existing drains being at the tope of the slope they are no good to me

My long term plan is to dig it all up, level it and put a mix of patio/astro-turf down with a drainage channel feeding back to my main drains

As my entire back is concrete I am at a loss on how to combat the flooding short term as to be honest I don't have the funds to completely re-do the back at this time

Any suggestions on a short-term fix to tie me over?

magicbastarder

you say the slope is quite pronounced and that the drains are near the house - is it possible that the water even when it pools, is still going to be lower than your existing drains? how much of a fall is there between the back of the house and the end of the garden?

in short - if you put drains in, you want the drains to fall toward where they leave the property; you might have difficulty in that the drains from the back of the garden have to run uphill which possibly could make the situation even worse.

Dannymole22

https://www.boards.ie/discussion/comment/121274869#Comment_121274869

The fall from highest to lowest could be 10cm give or take.

The plan long term is to raise and level it with a drain channel running parallel to the back of the house. Obviously leave enough fall when raising for the water to run into the drain channel which will feed back to my main drainage closer to the house

In the extremely crude diagram below X is my existing drains and the arrows are the new angle of slope I am proposing to run into the new proposed channel drain (squiggly lines)

FishOnABike

What's beyond the end of your garden?

I don't think you really want to try dealing with flooding by diverting it to your main drains. The solution could be worse than the problem.

Would a soakpit at the end of your garden work?

Dannymole22

https://www.boards.ie/discussion/comment/121274974#Comment_121274974

The flooding would only be the amount of water that would fall with any normal rainfall my problem is due to nature of the slope all the rainfall is being channeled to one particular area of my back garden. Once the water lodges there it has no where else to go

There is a railway line on the other side of my back wall

https://www.boards.ie/discussion/comment/121274974#Comment_121274974

Or cut a drainage hole into the wall with a few corrugated drainage pipes into the ground? French drainage pattern

The Continental Op

Hmmmm - flooding ;-)

Ouch! Hope it does not reach the house

Dannymole22

https://www.boards.ie/discussion/comment/121275160#Comment_121275160

I'm going to chance a water pump as it is only a short term solution needed. Hopefully will be able to get a long term solution put in by the time spring rolls around

https://www.boards.ie/discussion/comment/121278449#Comment_121278449

Okay I take back using the word flood after seeing this

The Continental Op

https://www.boards.ie/discussion/comment/121278564#Comment_121278564

It only reaches the house when we get that sort of rain plus a storm and a very high tide at the same time. Didn't have the storm and very high tide this time.

Worst part is just clearing the mess of leaves and crap that get caught up in all the plants. Can't even walk on the grass until its dried out a bit. Waters all gone but walking on the grass leaves muddy footprints.

standardg60

https://www.boards.ie/discussion/comment/121278697#Comment_121278697

Just drill a few holes through the concrete with a 12 or 15 mm bit

Stephenc66

OP is the ground behind your back wall lower or higher than your garden?

Dannymole22

https://www.boards.ie/discussion/comment/121279411#Comment_121279411

It is higher, so drilling holes wouldn't help. I may need to go to the other side and do a bit of digging

macraignil

Your long term plan to change the slope of the garden so the water flows toward the drain close to the house sounds like a bad idea. If the drain is blocked you will have made changes to channel the water into the back of your house. If you can wait until we get some dry weather could you just dig a pit where the water is currently gathering and turn it into a soak away by filling it back up with larger stones that will allow the water get to the lower soil levels faster and drain away or is the water table in your area too high for this to work?

https://www.diydoctor.org.uk/projects/soakaway-water-drainage-system.htm

The Continental Op

RE: Height of water table. In a lot of places you just can't tell by the way standing water collects or even from a shallow plant pot depth hole. On new houses there is often a hard pan layer from builders compacting the soil and burying their rubbish. Always worth digging a decent hole to check even it if means bailing out water to get to down. I'd always take out a hole at least 60 cm deep (ideally deeper) and leave it for a while before claiming a high water table.

In the picture of the flood above it all drains away quite quickly but some areas of the garden are heavy clay, judging by those areas you'd think the water table was really high but digging through it brings you down through multiple layers of sand, silt and large stone which drain very well. In some areas of the garden you can go down 2 meters (with a digger bucket) and it drains really well but in the areas of clay nearby you can dig out a hole for a shrub and when its been wet like recently it will immediately fill with water.

Alkers

Can you post some pictures to better show what you're working with? What's the distance to the back of the garden?

If it's short, in the interim you could dig a small sump and get a 100e dirty water pump to pump into the drainage nearer your house.

standardg60

Op's garden is entirely concreted, hence why I suggested drilling a few holes through it.