I'm really not sure @danny_ryan95, as it's not something I've ever had to do. We have vert wet ground here and we just get used to not walking on the grass much! I've created new lawns, but I do the prep to alleviate the excessive rainfall and make the drainage decent enough. I don't think you need to go to a lot of trouble with reservoirs etc - just dig out a reasonable trench in behind those gravel boards and add the gravel. It's a fairly standard method when making retaining walls. I've done it in a previous garden when we extended the house, built a deck and terraced the remaining sections of the site
It's a place where beautiful isn't enough of a word....
I live in west central Scotland - not where that photo is...
I'm thinking of putting a deeper level of stones at the front to account for the fact that, if done correctly, there should be significantly more water than in other stone areas.
When the patio gets fitted, it'll be angled towards the stones too. I'll probably 'dry run' it too before we put the stones in, and pour some water at the top of the garden to make sure it moves the way I want it to.
Hi Danny, what you're talking about makes sense. Stone filled trenches are basically what French Drains are, and if you connect them to a deeper stone filled trench to the back of that wall, with gaps or weep holes to allow the water out, it will work. You need to line the trenches with geo textile membrane to help stop them clogging up with soil. It needs to be permeable, not waterproof, so water can seep in through it. Ideally include a perforated pipe, lined with permeable geo textile, linking to the deep trench at the back of the wall.
You might find the trenches are too far apart to drain the whole lawn effectively, if your soil is very clayey. You could add other trenches through the lawn in a similar style but rather than having the stones visible, wrap the geo textile over the top and finish with soil and turf on top. You need at least 6" of cover or the trenches will become visible in dry weather.
Hi Danny, what you're talking about makes sense. Stone filled trenches are basically what French Drains are, and if you connect them to a deeper stone filled trench to the back of that wall, with gaps or weep holes to allow the water out, it will work. You need to line the trenches with geo textile membrane to help stop them clogging up with soil. Ideally include a perforated pipe linking to the back of the wall.
You might find the trenches are too far apart to drain the whole lawn effectively, if your soil is very clayey. You could add other trenches through the lawn in a similar style but rather than having the stones visible, wrap the geo textile over the top and finish with soil and turf on top. You need at least 6" of cover or the trenches will become visible in dry weather.
Thank you. Quite an interesting concept that it is essentially a French drain, I hadn't thought of that, and that I'm essentially half way to doing the whole thing. What might be worth doing is, if there's no or little improvement, adding in more drains and connecting them to the system I'll already have in.
I was considering what to use to stop the the wholes through the concrete clogging up, and a perforated pipe sounds like exactly what I'll need. I'm thinking I'll dig deeper than I will in the rest of the stone beds, to allow for more water, and the perforated pipe and probably some cheaper stones to build the level up, and then the decorative stones for the last layer.
I'll angle all of the stones around the patio so that they drain towards the front too, which should help reach some of the more central parts of the garden, but we'll see just how much of a factor it is.
Some of the worst draining areas of the garden are actually areas that will become either patio or stone beds, so that resolves some of the issue immediately.
So I think I have it. The arrows on my diagram indicate drainage direction. Sorry for the quality, was a quick mock up via Paint.
All of the drainage area's will have perforated pipes, and I'm going to connect with T junctions where appropriate.
I've read about how French drains are made. And I can't help but think that surely a non-permeable membrane is best being used to line the trench, so that as much water as possible enters the drain, rather than being soaked back into the ground, and then obviously a permeable membrane around the pipes.
What I'm considering now is the part where it meets the wall. I don't think it'll work by putting the end of the pipe to meet the wall, as they'll only be the size of a drillbit so I was hoping for 2-3 holes. I'm thinking of something that will essentially create a reservoir of water, maybe a non-permeable membrane on the bottom and the non-wall side, with a permeable membrane against the wall that has 2-3 holes drilled in.
You need a permeable membrane - otherwise the water won't get in!
The water soaks into the trench from the surrounding soil, and is then flows out through the stones/perf. pipe (the path of least resistance to low ground). Where water flows into the trench from hard paving, rather than through the soil, it will flow out along the trench rather than into the (less permeable) soil.
All you need do at the end is terminate the perf. pipes in the gravel trench behind the wall. They don't need to connect to anything. Water will enter the gravel trench and find it's way out via gaps in the wall or whatever holes you drill.
Remember water will always 'try' to get to low ground and will flow along the path of least resistance, you just need to facilitate that.
I'm thinking rather than drilling into the wall, you could lift the concrete gravel boards and place something at the bottom (e.g. some stones to prop it up) to make a bigger gap. Water will then seep out through it into the gravel area by your bins. There may be enough gaps to allow this already but it wouldn't hurt.
You need a permeable membrane - otherwise the water won't get in!
The water soaks into the trench from the surrounding soil, and is then flows out through the stones/perf. pipe (the path of least resistance to low ground). Where water flows into the trench from hard paving, rather than through the soil, it will flow out along the trench rather than into the (less permeable) soil.
All you need do at the end is terminate the perf. pipes in the gravel trench behind the wall. They don't need to connect to anything. Water will enter the gravel trench and find it's way out via gaps in the wall or whatever holes you drill.
Remember water will always 'try' to get to low ground and will flow along the path of least resistance, you just need to facilitate that.
So water would enter the trench directly from the soil 'walls' rather than running off the top of the turf? So it would pass from the soil through the permeable membrane into the trench and then through the permeable 'sock' and into the pipe.
My mentality was that most water would 'drop' into the trench either directly or as run off, and that the use of a non-permeable membrane to line the trench would allow water retention, and then a permeable 'sock' to get the water into the pipe.
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I don't think you need to go to a lot of trouble with reservoirs etc - just dig out a reasonable trench in behind those gravel boards and add the gravel. It's a fairly standard method when making retaining walls. I've done it in a previous garden when we extended the house, built a deck and terraced the remaining sections of the site
I live in west central Scotland - not where that photo is...
When the patio gets fitted, it'll be angled towards the stones too. I'll probably 'dry run' it too before we put the stones in, and pour some water at the top of the garden to make sure it moves the way I want it to.
You might find the trenches are too far apart to drain the whole lawn effectively, if your soil is very clayey. You could add other trenches through the lawn in a similar style but rather than having the stones visible, wrap the geo textile over the top and finish with soil and turf on top. You need at least 6" of cover or the trenches will become visible in dry weather.
I was considering what to use to stop the the wholes through the concrete clogging up, and a perforated pipe sounds like exactly what I'll need. I'm thinking I'll dig deeper than I will in the rest of the stone beds, to allow for more water, and the perforated pipe and probably some cheaper stones to build the level up, and then the decorative stones for the last layer.
I'll angle all of the stones around the patio so that they drain towards the front too, which should help reach some of the more central parts of the garden, but we'll see just how much of a factor it is.
Some of the worst draining areas of the garden are actually areas that will become either patio or stone beds, so that resolves some of the issue immediately.
All of the drainage area's will have perforated pipes, and I'm going to connect with T junctions where appropriate.
I've read about how French drains are made. And I can't help but think that surely a non-permeable membrane is best being used to line the trench, so that as much water as possible enters the drain, rather than being soaked back into the ground, and then obviously a permeable membrane around the pipes.
What I'm considering now is the part where it meets the wall. I don't think it'll work by putting the end of the pipe to meet the wall, as they'll only be the size of a drillbit so I was hoping for 2-3 holes. I'm thinking of something that will essentially create a reservoir of water, maybe a non-permeable membrane on the bottom and the non-wall side, with a permeable membrane against the wall that has 2-3 holes drilled in.
The water soaks into the trench from the surrounding soil, and is then flows out through the stones/perf. pipe (the path of least resistance to low ground). Where water flows into the trench from hard paving, rather than through the soil, it will flow out along the trench rather than into the (less permeable) soil.
All you need do at the end is terminate the perf. pipes in the gravel trench behind the wall. They don't need to connect to anything. Water will enter the gravel trench and find it's way out via gaps in the wall or whatever holes you drill.
Remember water will always 'try' to get to low ground and will flow along the path of least resistance, you just need to facilitate that.
My mentality was that most water would 'drop' into the trench either directly or as run off, and that the use of a non-permeable membrane to line the trench would allow water retention, and then a permeable 'sock' to get the water into the pipe.