Garden Drainage, Help with design

Joe10000

Inspired by others on here and sick of the dirt coming into the house because of the water logged garden I am going to start trying to solve this problem once and for all.

The house is a typical bungalow seen on every road in rural Ireland. The front garden drainage is adequate but the back garden is a mud bath 9 or 10 months of the year. We are in the west of the country and the rain never seems to stop, I think we have had one dry day since the start of October...

I have read every other thread on here on the subject and done some research on french drains and percolated piping and have a fair idea of what to do. However the garden is 50 metres wide and thus presents a challenge in laying out the drainage works.

I have included a schematic of the garden to give you an idea of the problems I face.

Ideally what i want to do is to pipe off the drain that runs from 1 to 2 and to use that pipe as the out for all the garden drainage. The problem is this ditch is at the highest point in the garden and therefore all the land I want to drain into it is in fact falling away from it. The possible solution for this is to dig the ditch another two feet down to create a fall but I'm not sure if creating this fall would be sufficient going against the natural fall.

Another possible solution would be to run one large french drain with two percolated pipes from left to right across the width of the garden and then turn it down into the drain at point number 2. If this was not adequate then I could go back later and dig smaller drains to feed into the main one.

I have attached two files. The first one is an excel spreadsheet (site layout)with an outline of the garden and house on sheet one and the two possible solutions I see on sheet 2 and 3.

The second file (house 3) is the architects site layout drawing.

Any suggestions or possible solutions would be very welcome, thanks.

rich_doit

Hi Joe,

Have same problem, about to start same project.
Garden 10m x 20m

From my research so far I am going to use Wavin Aqua Cell Lite or similar brand - looks like the way to go for storm water storage slow natural release. Although i think the wavin 1's here cost approx 130euro found them in uk for 40gbp, so looking to get one for 40euro.
Dig em deep wrap in geotextile coating and run some HDPE drainage piping to them.

Picking up from other threads key is to get down through the compacted layers.

Any way good, let us know how ya get on. I will post some phot when get the project under way.

Cheers

ponddigger

hi rd ,when i am building pondless waterfalls,i use plastic beer creates to fill the bason.they cost me 2 e each at car boot sale.they would do the same job as aqua cell blocks,post some photos of your projects.:Dponddigger:D

Sonnenblumen

OP
about two years ago we had to tackle a much more severe problem (natural spring under garage/house foundation, run off from local golf course etc). Problem was critical as there were substantial volumes of water involved which made a very large site persistently damp and was beginning to affect the stability of the property's foundation etc.

All works were satisfactorily completed and the site was comprehensively re-landscaped and the old (clay pipe sewerage pipework) was also all replaced.

The site also had a natural gradient from rear (high) to front.

It is important to use adequate pipework (we used 150mm) and that all pipework be adequately protected with a membrane and embedded (middle) in 600mm drainage gravel and in our case topped with 600-900mm topsoil. Backfilling can be done in stages to control soil compaction and some final minor adjustments at end to ensure good grading/levelling. It is very important that when using natural falls that the water can escape quickly.

I think looking at your sketches you will need to instal a more comprehensive network of land drains and divert to front boundary of site. Run-off/collected waters can be harvested, used to irrigate perimeter planting, soakage/percolation area, used as feed for pond etc etc. There are many ways of using the water besides simply getting 'rid' of it.

it can be quite a daunting challenge but stay calm and you'll get it sorted.

ponddigger

hi great idea by last poster about harvesting the run off.some photos of how you might do it :Dponddigger:D

Joe10000

Thanks Sonnenblumen, did you ever consider large dry wells as part of the solution ?

rich_doit

Thanks Ponddigger, thought had crossed my mind but you've now concreted it.
Found good site http://www.plastics-express.co.uk/ cheapest aqua cell so far 40gbp.
Was in Balbriggan today so popped into Wavin but they don't do over counter sales, anyway told me try near builders merchant 70euro for 1 x aqua cell.

Get a lot off empty plastic beer crates for that and a full one to help with the digging!

Cheers

Sonnenblumen

Joe10000 wrote: »

Thanks Sonnenblumen, did you ever consider large dry wells as part of the solution ?

We considered several solutions up to and including programmed pump stations running 24*7. Dry wells/Soak pits are limited by capacity to absorb and release water and max out pretty quickly when large amounts are involved. In our experience land drains can cope with most typical urban/small rural sites where seasonal dampness is a recurring problem. Sites which are damp throughout the year, the solution needs to be much more efficient to removing excess water on a more regular basis.

Dry wells are IMO basically soakage pits in kit form but just as vulnerable/limiting as traditional soak pits.

Joe10000

I can check Monday but does anyone know roughly the price of stone ?

Had a guy here today and he says I need 60ton 2" sandstone drainage chip and 20ton pea gravel.

Thanks

rich_doit

www.pavingexpert.com

Any prices yet for gravel?

Im also enquiring for hardcore and sharp sand 5 & 2ton.

Also any prices for aquacells / yellow drainage pipe 3inch 50metres 40 euro quote from gings laois.

ponddigger some gr8 threads, photos and posts.

Sonnenblumen

Avoid wasting money and only use pea gravel in trenches. For pits use a mix rough grade stone (limestone much cheaper than sandstone) 40mm - 70mm.