House downpipes into old school soakpits

Forums › Home Workshop DIY › House downpipes into old school soakpits - blocked

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zenourn

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#2521427 12-Jul-2020 13:25

Bung: A vacuum truck might work with a chamber style soak pit but not with a hole backfilled with rubble that won't go up the suction hose.

Completely agree. Mine were filled with ~50 mm stones and a vacuum truck either would of done nothing or made the entire area collapse if it managed to suck up the stones.

AklBen

102 posts

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#2521580 12-Jul-2020 20:35

I would just imagine that you'd be able to shovel the stones out, wash 'em, clean out the pit and put them all back in...

nickb800

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#2521625 13-Jul-2020 07:26

Cleaning out silt among the stones would restore the soakpit's ability to detain water. However, if it's been left to silt up for a long time, then all the pores in the soil surrounding the soakpit will be filled up with silt, which will slow down the soil's ability to dissipate the water.

It depends on how free draining your ground is - if it's something really free-draining like scoria then you can probably recover the soak pit, but if it's clay then you're probably better just digging a new soak pit

D1023319

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#2524493 17-Jul-2020 07:32

The question not discussed here is where is the silt thats clogging the sock pit come from?
If its not from the water source, a trap at the start wont be that effective.

Rather than a single large hole - ours is a long trench with drainage coil covered in silt sock and back filled with pea metal

robjg63:

Bung: I remember as a child my father digging a huge soak pit and filling it with broken concrete. Years later it had stopped working and when I took the top off it was completely full of very fine silt. It was so dense that it would have been a waste of time trying to dig it out compared with digging a new soak hole.

There are companies that will clean them out. They usually use vacuum trucks to clear the silt:

https://duttonstormwater.co.nz/stormwater-maintenance-services-auckland/soak-hole-maintenance/#:~:text=Soak%20Hole%20cleaning&text=Soak%20holes%20are%20manholes%20that,and%20this%20can%20cause%20flooding.

Bung

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#2524511 17-Jul-2020 08:39

D1023319:
The question not discussed here is where is the silt thats clogging the sock pit come from?
If its not from the water source, a trap at the start wont be that effective.

Rather than a single large hole - ours is a long trench with drainage coil covered in silt sock and back filled with pea metal

At the old family home it was wind blown dust off the roof. Heavier grains of sand tended to stay in the gutters but the water carried the finest particles into the pit. I think if it is fine enough it will stay in suspension long enough to get through simple silt traps. In Wellington the council filter stormwater at Waitangi Park through wetlands before it reaches the harbour.

AklBen

102 posts

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#2524521 17-Jul-2020 08:58

D1023319:

Rather than a single large hole - ours is a long trench with drainage coil covered in silt sock and back filled with pea metal

Sounds good. But, your silt sock is designed to prevent silt entering the drainage coil or prevent silt from escaping the drainage coil?

Because I wonder if you were to dig it up if your drainage coil was full of silt?

FineWine

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Nurse (R)

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#2524582 17-Jul-2020 10:23

I send a link to this topic to my sister-in-law in Half Moon Bay, Auckland as we had been talking that she had made a feature out of her soak pit. She is at the bottom end of a cluster of 6 town houses and soak pit collects all the drainage off the large common driveway. The water level only goes up to the top when it rains, and when it silts up, she digs it out in the summer when it dries out. She has yet to finish the painting/decorating.

Whilst the difficult we can do immediately, the impossible takes a bit longer. However, miracles you will have to wait for.

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

kotuku4

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#2524760 17-Jul-2020 13:52

The pond or rain garden concept is ok. If possible get the soakage well away from buildings, structures, vehicle access.*

Cirtex rainsmart are a cost effective product we use for in ground storage. Still need a soakage footprint of uncompacted ground with some soakage.

The bigger the base area and shallower the better. All wrapped in geotextile filter fabric. If you can trap or divert debris/silt first, so much the better.

Provides in ground storage and soakage. Recycled plastic grates provide 95% void space ratio, compared to typical 100-150mm drainage cobbles of 38% at best.

* These can be installed under trafficable areas areas manufacturers specifications. May need 600mm cover and geogrid reinforcement.

AklBen

102 posts

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#2525830 19-Jul-2020 20:56

kotuku4:

The pond or rain garden concept is ok. If possible get the soakage well away from buildings, structures, vehicle access.*

Cirtex rainsmart are a cost effective product we use for in ground storage. Still need a soakage footprint of uncompacted ground with some soakage.

The bigger the base area and shallower the better. All wrapped in geotextile filter fabric. If you can trap or divert debris/silt first, so much the better.

Provides in ground storage and soakage. Recycled plastic grates provide 95% void space ratio, compared to typical 100-150mm drainage cobbles of 38% at best.

* These can be installed under trafficable areas areas manufacturers specifications. May need 600mm cover and geogrid reinforcement.

Where does Joe Public buy small applications of it from?

D1023319

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#2525991 20-Jul-2020 12:59

AklBen:

D1023319:

Rather than a single large hole - ours is a long trench with drainage coil covered in silt sock and back filled with pea metal

Sounds good. But, your silt sock is designed to prevent silt entering the drainage coil or prevent silt from escaping the drainage coil?

Because I wonder if you were to dig it up if your drainage coil was full of silt?

I havent had need to to dig it up after 15 years as it still works

Yes you are right the sock stops ground silt entering the coil at the drainage end but i forgot to mention the source water is dumped into a trap.
A pipe from the top of the trap takes the water to the coil.
Then every year or so I empty the trap of silt.

kotuku4

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#2526004 20-Jul-2020 13:41

Where does Joe Public buy small applications of it from?

https://cirtexresidential.co.nz/cirtex-products/stormwater-drainage/smartsoak/

I see residential product now listed as smart soak. Suppliers are listed, or try a local drainlayer.

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