Hello,
due to the heavy rainfall in the past few days, I have once again been looking into rainwater infiltration. The background is that we have clay soil, where rainwater tends to accumulate.
Normal rain isn't much of an issue... but when there is heavier rain, water first pools on our lawn. Once the rain stops, it usually disappears within 5-6 hours... but it still bothers me, especially during the current "rainy season," as it happens quite often.
Based on my current knowledge, the soil profile is as follows:
- 50 cm (20 inches) of topsoil
- at least 1.5-2.0 meters (5-6.5 feet) of clay
- unknown layers below
The landscaping company once dug a hole 2-2.5 meters (6.5-8 feet) deep (the small excavator couldn't go any deeper). There was still clay soil present at that depth... unfortunately, I don’t know how deep the clay layer goes.
My idea, which I found online, is to drill several deep holes into the soil with an earth auger and then refill them... always hoping to break through the clay layer. The earth augers I found online can be extended up to 10 meters (33 feet).
My questions are:
1. Has anyone had experience with this? Is the effort worth it, or is the improvement too small to justify it?
2. The depth of the holes depends on the thickness of the clay layer... but what diameter is sufficient? The largest earth auger I saw had a diameter of 20 cm (8 inches)... or is one with 15 cm (6 inches) enough?
Of course, the larger the diameter, the more effort the drilling requires and the more material you need to refill.
3. On to the next question: What is best to use for refilling? Gravel or pebbles? I have read that pebbles tend to get clogged quickly... but they are definitely more permeable.
due to the heavy rainfall in the past few days, I have once again been looking into rainwater infiltration. The background is that we have clay soil, where rainwater tends to accumulate.
Normal rain isn't much of an issue... but when there is heavier rain, water first pools on our lawn. Once the rain stops, it usually disappears within 5-6 hours... but it still bothers me, especially during the current "rainy season," as it happens quite often.
Based on my current knowledge, the soil profile is as follows:
- 50 cm (20 inches) of topsoil
- at least 1.5-2.0 meters (5-6.5 feet) of clay
- unknown layers below
The landscaping company once dug a hole 2-2.5 meters (6.5-8 feet) deep (the small excavator couldn't go any deeper). There was still clay soil present at that depth... unfortunately, I don’t know how deep the clay layer goes.
My idea, which I found online, is to drill several deep holes into the soil with an earth auger and then refill them... always hoping to break through the clay layer. The earth augers I found online can be extended up to 10 meters (33 feet).
My questions are:
1. Has anyone had experience with this? Is the effort worth it, or is the improvement too small to justify it?
2. The depth of the holes depends on the thickness of the clay layer... but what diameter is sufficient? The largest earth auger I saw had a diameter of 20 cm (8 inches)... or is one with 15 cm (6 inches) enough?
Of course, the larger the diameter, the more effort the drilling requires and the more material you need to refill.
3. On to the next question: What is best to use for refilling? Gravel or pebbles? I have read that pebbles tend to get clogged quickly... but they are definitely more permeable.
Hello,
your topic is a few days old, but I’ll reply anyway.
We have the same problem, living in SL-H, and unfortunately it rains very often. On top of that, our soil is much worse, so rainwater doesn’t drain away when it rains a bit heavier.
I have tried several different approaches as a result.
I also tried drilling holes.
We built a sand playground for the children of about 18m2 (194ft2). I dug it out 50cm (20 inches) deep and filled it with sand, but after rainwater always remained standing and didn’t drain. So, I drilled 10 DN 300 (12-inch) holes on the outer sides, filled them with coarse gravel because I thought – water will enter, there’s plenty of space, and it can infiltrate – but that didn’t work at all. So I removed the sand, built an infiltration tunnel with a capacity of 900 liters (238 gallons) in the middle, with an overflow to a soakaway shaft with a solid base and lid. I installed an automatic pump in this. When the infiltration tunnel is full and the water overflows, it is automatically pumped into my rainwater drainage system and removed. Since then, there have been no puddles left on the sand. The lawn next to it is also doing better because the water that moves underground through the clay soil flows into the sandbox and disappears there.
Under the newly laid part of the lawn, I later installed infiltration by placing four long pipes embedded in gravel, and also installed a yard drain directly in the lawn so that water actually standing on the grass can drain off.
There are still a few spots that stay very wet if it rains for a long time, but the main area is noticeably better and dries faster.
your topic is a few days old, but I’ll reply anyway.
We have the same problem, living in SL-H, and unfortunately it rains very often. On top of that, our soil is much worse, so rainwater doesn’t drain away when it rains a bit heavier.
I have tried several different approaches as a result.
I also tried drilling holes.
We built a sand playground for the children of about 18m2 (194ft2). I dug it out 50cm (20 inches) deep and filled it with sand, but after rainwater always remained standing and didn’t drain. So, I drilled 10 DN 300 (12-inch) holes on the outer sides, filled them with coarse gravel because I thought – water will enter, there’s plenty of space, and it can infiltrate – but that didn’t work at all. So I removed the sand, built an infiltration tunnel with a capacity of 900 liters (238 gallons) in the middle, with an overflow to a soakaway shaft with a solid base and lid. I installed an automatic pump in this. When the infiltration tunnel is full and the water overflows, it is automatically pumped into my rainwater drainage system and removed. Since then, there have been no puddles left on the sand. The lawn next to it is also doing better because the water that moves underground through the clay soil flows into the sandbox and disappears there.
Under the newly laid part of the lawn, I later installed infiltration by placing four long pipes embedded in gravel, and also installed a yard drain directly in the lawn so that water actually standing on the grass can drain off.
There are still a few spots that stay very wet if it rains for a long time, but the main area is noticeably better and dries faster.
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