advice please, stormwater grate blocking

Forums › Home Workshop DIY › advice please, stormwater grate blocking

nickreno

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#279818 11-Nov-2020 09:49

Hi -

interested in your thoughts on possible solutions - I have a stormwater sump that has its grate blocked by leaves & debris during rains.

It collects run-off from around 200sqm of driveway, and collects leaves en-route so doesn't drain sufficienly quickly if there is a dry spell then heavy rain. It's small - 250mm square - and its become an issue once the driveway was re-surfaced (previously the pot-holes collected the leaves!). It is connected to a 100mm stormwater pipe with a very decent slope, which is very capable of handling any flows provided they get into the sump or system itself! It is on the edge of the driveway, so a larger sump would need to support occasional vehicle traffic.

I'm considering either getting a larger one installed, or a 5m strip-drain across the driveway - has anyone got any advice around this, would a larger sump of a strip-drain be a batter solution, or something else?

Image:

timmmay

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#2601567 11-Nov-2020 10:34

This may be a silly question, but does it have a lid? I have a sump that looks very similar that has a slotted cover to let water in but not large debris. I found leaves got in, so I put a fine plastic mesh in which catches leaves, the mesh is just something from the hardware store that I got a sheet of from the garden dept.

MikeAqua

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#2601588 11-Nov-2020 10:46

If the lid with mesh doesn't work (it may just block, transferring the problem)

Stay on top of the leaves. I have the same problem in our driveway, so I bought a leaf sucker; Or

Make a deeper (more important than larger) sump and keep it clean; Or

Add a second sump up-stream of the one pictured. It will hopefully trap the leaves and the water can flow through to the second sump.

A strip drain will help, but at some stage you'll have to remove leaves from it or it will block.

Basically any solution involves you dealing with the leaves at some stage.

Mike

nickreno

28 posts

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#2601589 11-Nov-2020 10:46

Hi - Yes it does have a lid, metal, flat, slotted - this is what has been clogging. I've attached one of those 'leaf catchers' upside down on top of it, like a weird hat, but the leaves block it all the way up (the water rises as leaves block the bottom, continues to rise until the top, then it spills - the sump is in a ~150mm depression). - they look too flimsy to attach the 'correct' way in an area with vehicles on it.

wellygary

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#2601599 11-Nov-2020 10:53

About the "leaf hat" , was wondering if you could make something line this work

https://www.bunnings.co.nz/everhard-easydrain-leaf-basket-suitable-for-260mm-pit-box_p4770227

nickreno

28 posts

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#2601612 11-Nov-2020 11:04

okay thanks - that is the thing i used. sounds like the solution is to keep on top of the leaves a lot more and try to trap them "upstream" -

davidcole

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#2601655 11-Nov-2020 11:47

We just had a sump put in, and one thing (and I asked about it) is it's got a right angle piece feedig the outlet pipe. With the other part deep into the water. The reason is that any leaves etc will sit on the top, and the water will be fed from lower down, meaning leaves wont block the pipe.

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neb

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#2601747 11-Nov-2020 13:11

If it doesn't get driven over, consider laying down one or more strips of plastic dragons teeth in front of it to catch the leaves before they get to the sump and clog it. They're those spiky things you can tack onto fences and the like to keep cats and possums from walking along them, not the long needle spikes but the low, blunt ones.

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nickreno

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#2601813 11-Nov-2020 13:44

thank you, these are really helpful suggestions. i will search & see what plastic "dragons teeth" i can find :)

neb

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#2601822 11-Nov-2020 13:55

nickreno:
thank you, these are really helpful suggestions. i will search & see what plastic "dragons teeth" i can find :)

Probably something like "pest spike" will get a better set of results, e.g. this, you'd just need to file down the points a bit if it's a trafficked area. Or more generally anything that will work as a screen, letting water through but catching floating stuff.

djtOtago

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#2601891 11-Nov-2020 15:20

May be you could fashion something out of some Gutter whiskers
https://www.mitre10.co.nz/shop/non-branded-roof-gutter-brush-1m/p/334679

MikeAqua

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#2601924 11-Nov-2020 16:06

davidcole:

We just had a sump put in, and one thing (and I asked about it) is it's got a right angle piece feedig the outlet pipe. With the other part deep into the water. The reason is that any leaves etc will sit on the top, and the water will be fed from lower down, meaning leaves wont block the pipe.

That is as cunning as an outhouse rat. I'm stealing that idea.

Mike

neb

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#2601929 11-Nov-2020 16:11

davidcole:
We just had a sump put in, and one thing (and I asked about it) is it's got a right angle piece feedig the outlet pipe. With the other part deep into the water. The reason is that any leaves etc will sit on the top, and the water will be fed from lower down, meaning leaves wont block the pipe.

It really depends on where the leaves are ending up, in the storm drain outside my house they end up on top of the grating over the drain forming a largely impermeable surface layer so that most of the water runs over the top and on to the next-lowest point of drainage. So it's not so much a problem of leaves blocking the drain but leaves rendering the grating that's meant to stop them impermeable.

kotuku4

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#2601941 11-Nov-2020 16:29

A larger sump, with a submerged outlet per building code would be desirable.

You could wrap a mesh over the grate, I have used nylon wind break mesh. This keeps all the leaf litter and general debris on top, where you can sweep it up.

I have a full sized sump in a right of way, and it's a pain to clean out. I don't want crap in the pipe as it discharges to soak pit under the driveway, once blocked up it would need excavating to fix.

WinNZ90

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#2615854 3-Dec-2020 19:26

How deep is it? and how much space is there from the top of the pipe to the top of the hole?

WinNZ90

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#2615860 3-Dec-2020 19:35

Ok someone mentioned one of these before and I saw it and then thought dome so I found the dome at bunnings too

Take the square one and nibble down the edges a little to fit the 250 sqm and then if you have to take a little of the bottom just enough to fit the pipe, don't cut off the whole base for the pipe, fit it around the pipe where you can. Get some water proof adhesive and glue that dome in the center, by the looks it will fit perfectly but I can't find dimensions for the dome.

This way you get double the action and quite a lot of water will still go down stop 90% of the leaves and the water should keep going down and barely block up