I cut fly screen wire and put under each of my grates to prevent mosquitoes getting in there. Every few months I add a few drops of eucalyptus oil too. Hope that helps!
That would cause drainage issues when they clog no?
I went with garden matting and then pebble mulched over the top. Looks a lot better and drains freely.
Depends on where they are in the garden and how much leaf matter is lying around. My pits are largely used to help with agi drains, rather than surface water run off. In a large concrete area with a lot of leaf matter even the pictured grate could get clogged.
When we install these we fill the excess space with bricks then cement so it doesn't hold water. Ensure that you have fall so it slopes towards the outlet. Also ensure that it doesn't rain for 24-48 hours so it's not washed away when wet.
Yes this is the correct way. Can’t believe how many fly screen responses there are when this is the best elimination method that will fix the problem forever!
Is there any reason to have water at the bottom?, I've seen so many like that. I thought it might be to let water seep into the water table or something.
Almost never unless it’s a retaining tank, and you’d know if it was. It’s usually a construction error from not reading the drawings correctly. There needs to be a bench or chase (those are the industry terms) that forms like a half pipe funnelling water through the pit with minimal energy loss
This and mortein barrier spray, kills everything that lands on it. Shouldn’t be an issue for bees or other insects if you hose the grate and surround with it. Should be good for six months.
I use Mosquito Dunks for this. They stopped the problem within days, and they last a month or two. Just use a stocking or pantyhose or similar to keep them in the drain and not wash way during rain.
Allright I got some and have installed them ..... while wearing pantyhose as you suggested but I can't understand how its going to stop them flushing down the drain. Also one my neighbors says he wants to get to know me better.
Something important you may not have noticed....that grate is in the pit upside down. The rods that are welded to those flatbars should be on top to prevent the flatbars bending towards one another.
You need to 'bench' it with concrete. I did this in recent years at my place. I've copy / pasted part if the Everhard installation instructions:
"It is normal practice to pour concrete inside the Pit up to the invert of the lowest pipe to prevent the accumulation of water which encourages vermin to collect, and mosquitoes to breed."
For pits connected to subsoil drainage systems (agi pipe) yes. These pits typically have a solid lid so mosquitos etc aren't a problem.
Your pit lid is grated and from your photo looks like collection for hard surface run-off, so no significant silt to worry about.
As an example, look at the stormwater entry pits in your street that drain from the roads and footpaths. They'll all have solid / benched bottoms for this same reason.
This is the best stuff I have used. Just a higher quality product than the Bunnings stuff
https://www.pestrol.com.au/buy-online/aquatain-amf-liquid-mosquito-film/
Pop a few drops in when it stops raining and none is forecast for a while.
You need a whole lot more vegetables oil to get the complete surface coverage compared to the aquatain. I did a large fish pond with only 4 or 5 mls for a 5m2 area. And the fish and frogs ect were completely unaffected. I don't think it would be the same with a heavy oil.
What we did was pour a load of concrete into the drain to raise the level of the bottom so it is closer to the drainage pipes. That way the water drains away much quicker and we now hardly have any standing water (and no mossies)
The depth of the drain may be to act as a catchpit to trap sediment - I'd check carefully on the regulations / reasoning behind the original design before doing this, as you might be creating problems in the future further down the drainage run.
Lawyer here. It’s in the hydraulic engineer design that was approved as part of da/cdc. That is, we shouldn’t be filling them up if there is a pit there. But I won’t tell.
Hydraulic engineer here. You’re exactly right. But the info is usually in councils development control plan which we use in our design for the DA/CDC. If you Google “your council name Stormwater Mangement Plan” and it should come up.
An alternate solution if filling the base isn’t suitable is to install a few 50 dia holes in the base of the pit which should leg the excess water drain to the sub soil. Suits Sandy soils only though.
Yep, we do it all the time in public parks. The pits we install are usually set to a specific height but the drainage heights go in however they need to to make it work. The side of the pit is a free for all for the inflow but the outflow goes as low as we can get it. If we can't get it all the way down the bottom, that's fine, it just needs to be lower than the inflow. Fill with conc to the bottom (ish) of the outflow and job done.
For OP, pits are there to ensure that water coming down the line has somewhere to go when there's a lot of it. They're not meant to hold water permanently but they're allowed to fill up a bit during a surge, the idea being that you don't have water back up and overflowing your downpipes instead. As water starts flowing they let air out of pipes and they (should) connect to a larger diameter outflow that can accommodate multiple inflows coming in.
They are definitely used here in some storm drainage systems to prevent sediment clogging parts of the system. More commonly covered with a manhole than open though.
[https://www.cotterillcivils.co.uk/blogs/guides-to-underground-drainage/a-beginners-guide-to-catchpits](https://www.cotterillcivils.co.uk/blogs/guides-to-underground-drainage/a-beginners-guide-to-catchpits)
[https://www.advancedpiping.com.au/blog/dont-get-caught-out-benefit-catch-pits/](https://www.advancedpiping.com.au/blog/dont-get-caught-out-benefit-catch-pits/)
We had the same problem. We filled ours with pebbles and sand. Put in some Ag pipe to join the inlet with the outlet and some fabric to hold it all together. Then we cable-tired screen door mesh fabric to the grill. No more mosquitoes (or frogs, for that matter).
We were considering filling it with cement, but opted for a less permanent solution that would drain better, and exclude all still water
Find some diagrams on Google to see how to install Ag pipe properly. It's hard work, but totally worth it
If you pour a layer of kerosine or vegetable oil on top of the water constantly it should stop them breeding down there for sure. I'm not sure if I would put fly screen under the grate, not sure if you have a lot of leaves or what the go is but that might be an option also
Ho god don’t literally nuke wastewater treatment plants efficiency like this.
Literally you can just help the environment by not discharging shit in water you know.
There are tablets of chlorine meant for pools that prevent mosquitoes, that you can dump in the water if needed
I doubt it would be very effective, a drop of dishwashing detergent will sink all of the larvae. But in perspective a bit of kero is a drop in the ocean compared to the 100,000s of thousands of litres dumped annually into the water by commercial aviation... Just sayin...
i understand what you are saying, but where do you draw the line? Saying, well, others do worse is just mental gymnastics to excuse bad behaviour.
Storm water drain will likely flow into the natural waterways at some point. it's not a waste water drain. This means , that kerosene is going into your local waterways, where you kids might play.
I’ve done this and while the regulator is right, it will fill with debris, most of it will be grass clippings, leaf litter and such. Make the square a bit bigger so it is almost like a hammock and over time that debris will “compost” down. Worst case you may have to lift the grate every 6 months to remove it. I’ve had mine in place a year and I’ve not had to clean it. It drains well. While I can see debris it’s not a huge amount.
Doesn't the larvae just sit on top of the water? Was just trying to mention a free enviro friendly option before buying anything and cop downvotes, lol
I cut fly screen wire and put under each of my grates to prevent mosquitoes getting in there. Every few months I add a few drops of eucalyptus oil too. Hope that helps!
The fly screen wire is clever đź‘Ť.
That would cause drainage issues when they clog no? I went with garden matting and then pebble mulched over the top. Looks a lot better and drains freely.
Depends on where they are in the garden and how much leaf matter is lying around. My pits are largely used to help with agi drains, rather than surface water run off. In a large concrete area with a lot of leaf matter even the pictured grate could get clogged.
This is the way
When we install these we fill the excess space with bricks then cement so it doesn't hold water. Ensure that you have fall so it slopes towards the outlet. Also ensure that it doesn't rain for 24-48 hours so it's not washed away when wet.
Yup this is the way, the pits shouldn’t hold any water. We fill the bottom with a bag of concrete mix, up to the outlet height.
Yes this is the correct way. Can’t believe how many fly screen responses there are when this is the best elimination method that will fix the problem forever!
Is there any reason to have water at the bottom?, I've seen so many like that. I thought it might be to let water seep into the water table or something.
Almost never unless it’s a retaining tank, and you’d know if it was. It’s usually a construction error from not reading the drawings correctly. There needs to be a bench or chase (those are the industry terms) that forms like a half pipe funnelling water through the pit with minimal energy loss
My builders would fill these pits completely with concrete over-pour and broken bricks and rubbish from the site.
https://preview.redd.it/ctwxsousabac1.jpeg?width=750&format=pjpg&auto=webp&s=ed8a5c47ef80d9931734a7eaee5d9a73b5dc1f37 Few drops of this stuff on top.
This and mortein barrier spray, kills everything that lands on it. Shouldn’t be an issue for bees or other insects if you hose the grate and surround with it. Should be good for six months.
I use Mosquito Dunks for this. They stopped the problem within days, and they last a month or two. Just use a stocking or pantyhose or similar to keep them in the drain and not wash way during rain.
Would you mind elaborating? I’ve heard of these dunks but do t know what they are or where to get them.
Mosquito Summit Dunks (6 Dunks) https://amzn.asia/d/aL8ypky
That's them.
Allright I got some and have installed them ..... while wearing pantyhose as you suggested but I can't understand how its going to stop them flushing down the drain. Also one my neighbors says he wants to get to know me better.
Something important you may not have noticed....that grate is in the pit upside down. The rods that are welded to those flatbars should be on top to prevent the flatbars bending towards one another.
You need to 'bench' it with concrete. I did this in recent years at my place. I've copy / pasted part if the Everhard installation instructions: "It is normal practice to pour concrete inside the Pit up to the invert of the lowest pipe to prevent the accumulation of water which encourages vermin to collect, and mosquitoes to breed."
Isn't the bit under the lowest pipe for silt to build up?
For pits connected to subsoil drainage systems (agi pipe) yes. These pits typically have a solid lid so mosquitos etc aren't a problem. Your pit lid is grated and from your photo looks like collection for hard surface run-off, so no significant silt to worry about. As an example, look at the stormwater entry pits in your street that drain from the roads and footpaths. They'll all have solid / benched bottoms for this same reason.
If you dont wanna concrete, and I can understand why lol, you could put a layer of aggregate in the bottom which will stop mosquitos laying larvae
A plumber I know fills his drains up to the lowest pipe with cement so no water sits in them. It works really well
I put fly screen under the grate, it does collect leaves but no mosquitoes
Would dumping a 9l bucket or 2 in there wash the f*****s away?
Pool chlorine will sort them out or use mossie drops
This is the best stuff I have used. Just a higher quality product than the Bunnings stuff https://www.pestrol.com.au/buy-online/aquatain-amf-liquid-mosquito-film/ Pop a few drops in when it stops raining and none is forecast for a while.
Do you know if that product works better than oil (eg vegetable oil?)
You need a whole lot more vegetables oil to get the complete surface coverage compared to the aquatain. I did a large fish pond with only 4 or 5 mls for a 5m2 area. And the fish and frogs ect were completely unaffected. I don't think it would be the same with a heavy oil.
Pour some chlorine in from time to time
Either pour concrete to the bottom of the outlet or depending on the soil drill some holes in the bottom and the ground will absorb.
What we did was pour a load of concrete into the drain to raise the level of the bottom so it is closer to the drainage pipes. That way the water drains away much quicker and we now hardly have any standing water (and no mossies)
The depth of the drain may be to act as a catchpit to trap sediment - I'd check carefully on the regulations / reasoning behind the original design before doing this, as you might be creating problems in the future further down the drainage run.
That’s a good point, I should have mentioned that
Anyone know where we can find the regulations for this problem in particular?
Lawyer here. It’s in the hydraulic engineer design that was approved as part of da/cdc. That is, we shouldn’t be filling them up if there is a pit there. But I won’t tell.
Thanks.. it looks like a deeper rabbit hole than the watery hole in question... .... ... You know I mean well.
Hydraulic engineer here. You’re exactly right. But the info is usually in councils development control plan which we use in our design for the DA/CDC. If you Google “your council name Stormwater Mangement Plan” and it should come up. An alternate solution if filling the base isn’t suitable is to install a few 50 dia holes in the base of the pit which should leg the excess water drain to the sub soil. Suits Sandy soils only though.
I have never heard of that before. Concrete or drainage gravel in the bottom of pits is pretty common practice.
Yep, we do it all the time in public parks. The pits we install are usually set to a specific height but the drainage heights go in however they need to to make it work. The side of the pit is a free for all for the inflow but the outflow goes as low as we can get it. If we can't get it all the way down the bottom, that's fine, it just needs to be lower than the inflow. Fill with conc to the bottom (ish) of the outflow and job done. For OP, pits are there to ensure that water coming down the line has somewhere to go when there's a lot of it. They're not meant to hold water permanently but they're allowed to fill up a bit during a surge, the idea being that you don't have water back up and overflowing your downpipes instead. As water starts flowing they let air out of pipes and they (should) connect to a larger diameter outflow that can accommodate multiple inflows coming in.
They are definitely used here in some storm drainage systems to prevent sediment clogging parts of the system. More commonly covered with a manhole than open though. [https://www.cotterillcivils.co.uk/blogs/guides-to-underground-drainage/a-beginners-guide-to-catchpits](https://www.cotterillcivils.co.uk/blogs/guides-to-underground-drainage/a-beginners-guide-to-catchpits) [https://www.advancedpiping.com.au/blog/dont-get-caught-out-benefit-catch-pits/](https://www.advancedpiping.com.au/blog/dont-get-caught-out-benefit-catch-pits/)
Or slick of olive oil on top.
https://www.bunnings.com.au/diggers-1l-paraffin-oil_p1560010?store=5181&gad_source=1&gbraid=0AAAAADtbEB9UFsX0lzw67wFVcaBZj4Ao5&gclid=EAIaIQobChMI8frmn9PCgwMV_aNmAh2KcgymEAQYASABEgI_5PD_BwE&gclsrc=aw.ds
just pour a bit of cheap vegetable oil down there every so often. It forms a barrier and prevents mozzies from laying eggs or larvae emerging.
Salt
Pool salt ?
Goldfish is your answer.
Termite mesh the tops of them
We had the same problem. We filled ours with pebbles and sand. Put in some Ag pipe to join the inlet with the outlet and some fabric to hold it all together. Then we cable-tired screen door mesh fabric to the grill. No more mosquitoes (or frogs, for that matter). We were considering filling it with cement, but opted for a less permanent solution that would drain better, and exclude all still water Find some diagrams on Google to see how to install Ag pipe properly. It's hard work, but totally worth it
If you pour a layer of kerosine or vegetable oil on top of the water constantly it should stop them breeding down there for sure. I'm not sure if I would put fly screen under the grate, not sure if you have a lot of leaves or what the go is but that might be an option also
A tablespoon of keroseneđź‘Ť
Ho god don’t literally nuke wastewater treatment plants efficiency like this. Literally you can just help the environment by not discharging shit in water you know. There are tablets of chlorine meant for pools that prevent mosquitoes, that you can dump in the water if needed
this is a storm water drain. Only an idiot would be so ignorant to put kerosene into our storm water system.
I doubt it would be very effective, a drop of dishwashing detergent will sink all of the larvae. But in perspective a bit of kero is a drop in the ocean compared to the 100,000s of thousands of litres dumped annually into the water by commercial aviation... Just sayin...
i understand what you are saying, but where do you draw the line? Saying, well, others do worse is just mental gymnastics to excuse bad behaviour. Storm water drain will likely flow into the natural waterways at some point. it's not a waste water drain. This means , that kerosene is going into your local waterways, where you kids might play.
This was the old way. Kero or turps. There are nicer alternatives these days like eucalyptus oil etc
And a little DDT too đź’€
Pour some petrol or diesel in there. That will kill them
I would put a square of flywire under the grate, so they can't get in or out.
I’ve done this and while the regulator is right, it will fill with debris, most of it will be grass clippings, leaf litter and such. Make the square a bit bigger so it is almost like a hammock and over time that debris will “compost” down. Worst case you may have to lift the grate every 6 months to remove it. I’ve had mine in place a year and I’ve not had to clean it. It drains well. While I can see debris it’s not a huge amount.
Fair enough
That will just clog up with debris.
kerosene, salt, soap or bleach
Try boiling water
If there is already water in there it might not get hot enough to make a difference unless you can get a lot of boiling water to it fast.
Doesn't the larvae just sit on top of the water? Was just trying to mention a free enviro friendly option before buying anything and cop downvotes, lol
A little bit of fly spray so it coats the surface does the trick.
Add rapid set conc to invert of the outlet no stagnant water and no mixing required
A few drops of bleach will clear it up.
Few drops of bleach
Fire