Yard drainage headache

[Biz55]

Hi

I have a yard and driveway which have been neglected for about 20 years. It is all covered in very coarse black gravel and chipping but much of this is now covered in thick moss and weeds.

Before I renew the gravel I need to do something about drainage. Large pools of water lie on the yard every time it rains and water seeps into the driveway from a field behind. Hence the big problem with moss.

So I was thinking of using french drains from the yard and driveway running down towards the public road. Unfortunately the driveway and yard contain three pipes : Water main, central heating and sewer. (I have attached a drawing)

So my question : Is a french drain going to be too difficult to achieve or is there a better solution ?

 

[Himaginn]

If you have a septic tank, assumedly, there is a leach field that the septic tank discharge drains into, so assumedly, there is no problem with natural drainage in your locality.
I would have thought that if the above assumptions are correct, it might be wiser to investigate why the flooding is not draining away.

If the flooding occurs faster than the natural drainage can cope with, by all means improve the drainage with french drains, purpose made pipes, etc, but to a soakaway on your property.
You are not allowed to drain private property onto public property.

 

[Biz55]

Thanks Himaginn

Could I run the french drain outlet from the yard and upper driveway into my sewer pipe so the water would discharge to my septic tank? Is that possible / allowed ?

 

[Himaginn]

I don't think that's a good idea. Septic tanks are sized to allow for the number of bedrooms/occupants so additional run-off would exceed the capacity.
Also, it would lead to increased thoughput of water, possibly not allowing the settlement of the septic tank contents, and possibly causing the dispersal of solids into the leach field.

Another alternative is rainwater harvesting.
What happens to your current rainwater?

You haven't indicated which end is which of the sewer to septic tank.
Is it possible that the flooding is partly caused by the inadequate drainage of the septic tank leach field.

 

[Biz55]

Thanks again.

As far as I can tell all the guttering from my house already empties into my sewer. The soakaway field for the septic tank commences about 1 hundred feet away to the right so it's too far away to cause be causing problem.

Part of my problem is that some areas of the yard have settled to a slightly lower level than the driveway allowing pools to form. I probably need to consider grading it to create a bit of a slope towards the driveway.

 

[theprinceofdarkness]

I would have thought french drains for this is wrong, turning from the drive into the yard would get your wheels into it. I wonder how you would get out? I would be more taken by an "Acco" type surface drain with a 4" land drain pipe under it. The land drain pipe should have a small slope and run to your septic tank where it couples into the land drain outlet. As mentioned it could pick up debris from your yard, but I believe most of this would stay in the drain any way, but you could stick in a sealed gully at the septic tank end, which would be useful to rod it out if required.
Frank

 

[Biz55]

Thanks Frank.

I've never actually seen a french drain. Only read about them. I saw a YouTube video of someone installing one on a driveway so I assumed they would support a vehicle.

Also not very familiar with Aco drains - would it drain water from the immediate surface area only ?

 

[Hugh Jaleak]

Rainwater should never be routed into a septic tank, in times of heavy rain the flow into the tank could be too much, and stir up the contents drastically, causing a high level of suspended solids to enter the leachfield, which in turn will soon bung up the leachfield, rendering the tank useless.

Normally a percolation test is carried out to determine the absorbtion rate of the soil to accept flow from a leachfield, but in clay soils, or when the water table is higher due to rainfall, then the soakaway may not always be as effective as required.

Also bear in mind, whilst you have a legal obligation to accept run off from higher ground onto your property, and your lower neighbour has the same obligations to accept your runoff, channeling the water artificially, and then discharging it onto the lower ground can then be classed as a statutory nuisance. I would be looking to grade the hardstanding area to allow the water to make its own way off rather than installing any form of drainage, depending on who, and/or what, is below you.

 

[theprinceofdarkness]

A french drain (named after a man not the race) is a trench which is filled with large pebbles which help the water evaporate. They do normally have a slope and a land drain at the end to cope with down pours. They can be seen at the sides on main roads. Acco drains are a posh gutter with a perforated cover and means of setting in in the ground. So water pours into them, leaving the surface dry. The end of the drain then goes to a land drain.
Frank