Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


tweake

1300 posts

Uber Geek


#303653 25-Feb-2023 15:41
Send private message

anyone done this at all?

 

just looking at storm water detention tanks due to the rain which was to much water for the pipes to carry. a previous owner had tanks here, which have long since been removed. so i was thinking about reinstating that to handle excessive rain especially as these big rain events seam to be getting more common every year.

 

catch is what size would i need ?? 


View this topic in a long page with up to 500 replies per page Create new topic
 1 | 2 | 3
SirHumphreyAppleby
2608 posts

Uber Geek


  #3041833 25-Feb-2023 15:45
Send private message

Multiple expected rainfall by capture area. You will get 1L of water per square meter for each mm of rain.


 
 
 

GoodSync. Easily back up and sync your files with GoodSync. Simple and secure file backup and synchronisation software will ensure that your files are never lost (affiliate link).
k1w1k1d
1243 posts

Uber Geek


  #3041841 25-Feb-2023 16:29
Send private message

Before you go too far, I would suggest that you look at the price of water tanks.


neb

neb
9368 posts

Uber Geek

Trusted
Lifetime subscriber

  #3041848 25-Feb-2023 16:52
Send private message

SirHumphreyAppleby:

Multiple expected rainfall by capture area. You will get 1L of water per square meter for each mm of rain.

 

 

And if you're trying to catch something at the level of what we've had recently you're probably not going to be able to do it unless you put in fairly sizeable concrete cisterns, and you'd have to carefully manage it so the preliminary soak doesn't fill the storage volume before the real downpour that you want to deal with begins. Have a look at things like rain gardens as a way of slowing down water volumes...



tweake

1300 posts

Uber Geek


  #3041904 25-Feb-2023 17:46
Send private message

all it really has to catch is what ever rain is more than what existing pipes can handle. normal rain before hand won't get caught because it will drain away as fast as it comes in. its still the stock 4" pipe out.

 

i suspect the choke point is the house/garage underground pipe to the town storm water pipe. its made for normal heavy rain, not this monster rain we seam to get now. even at work we added 6" pipe and its like we did nothing. 


neb

neb
9368 posts

Uber Geek

Trusted
Lifetime subscriber

  #3041911 25-Feb-2023 18:30
Send private message

Ah, in that case and if it's purely roof catch go with @SirHumphreyAppleby's suggestion. Even then though with a typical roof area of 150m2 and 100mm rain, a few days ago in Orkland but only a third of 31st Jan, that's 15,000L to catch and that's a big tank.

wally22
504 posts

Ultimate Geek

Trusted
Lifetime subscriber

  #3041915 25-Feb-2023 18:58
Send private message

The underlying principle of detention tanks in NZ does not really take into account the recent rainfalls. I interpreted the concept as a way of limiting capital outlay on infrastructure by the councils.


Benoire
2648 posts

Uber Geek


  #3041962 25-Feb-2023 19:03
Send private message

wally22:

 

The underlying principle of detention tanks in NZ does not really take into account the recent rainfalls. I interpreted the concept as a way of limiting capital outlay on infrastructure by the councils.

 

 

The concept is more about reducing the initial peak flow and spread it over a longer period to avoid overwhelming the piped network which only has a 10% AEP service level (i.e. 1 in 10 year).  Beyond this, its overland flow with paths getting more pronounced and deeper as the rainfall continues.




tweake

1300 posts

Uber Geek


  #3041964 25-Feb-2023 19:14
Send private message

neb: Ah, in that case and if it's purely roof catch go with @SirHumphreyAppleby's suggestion. Even then though with a typical roof area of 150m2 and 100mm rain, a few days ago in Orkland but only a third of 31st Jan, that's 15,000L to catch and that's a big tank.

 

but over what time period and how much is going out the outlet. you might have 15,000 litres coming into the tank but 14,000 litres is going out at the same time. your not trying to save the water, just supply a bit of space to handle those short bursts of insanely heavy rain.

 

 


neb

neb
9368 posts

Uber Geek

Trusted
Lifetime subscriber

  #3041966 25-Feb-2023 19:23
Send private message

Yeah, it depends where the chokepoint is, if it's a 100mm pipe feeding a 150mm main that's also fed by several other 100mm pipes from neighbouring properties then the tank may need to retain the entire rain load until it's possible to put more water down the outflow.

 

 

More data needed :-).

Benoire
2648 posts

Uber Geek


  #3041967 25-Feb-2023 19:54
Send private message

Look at smaf1/2 area requirements from the AC storm water code of practice along with the Auckland unitary plan, these will give a good idea of how much capacity you might need to actually do anything helpful.

neb

neb
9368 posts

Uber Geek

Trusted
Lifetime subscriber

  #3041974 25-Feb-2023 20:20
Send private message

Benoire: AC storm water code of practice along with the Auckland unitary plan

 

 

How realistic is that though? In other words if you follow that you can claim compliance with requirements but will it handle what we're seeing now rather than what the plan was written for?

Benoire
2648 posts

Uber Geek


  #3041975 25-Feb-2023 20:28
Send private message

No, TP108 (rainfall patterns for Auckland) has not been updated to reflect the shifting nature of the events, but you can generally pick up the amount from Metservice etc. and then use the calcs in these rules to see how much capacity you will need... in any avent, for my 90m2 house with 130m2 roof area a 30kL tank provided enough capacity to take the event But the subsequent days would have overflowed.

 

Be mindful, however, that overland flows could add to your own land area volume and reduce the ability for any tank to act as you think.

 

 

 

My goal for my next house is to plumb in the rainwater as the primary source for my house and then use the mains when it runs low; it will be cleaner and less metals compared to the current watercare supply and generally a standard rain event in winter in Titirangi will supply ~10 days worth of water for me (nearly 5000L) with a historic summer level in feb providing about 12 days worth of fresh water.


tweake

1300 posts

Uber Geek


  #3041982 25-Feb-2023 21:07
Send private message

neb: Yeah, it depends where the chokepoint is, if it's a 100mm pipe feeding a 150mm main that's also fed by several other 100mm pipes from neighbouring properties then the tank may need to retain the entire rain load until it's possible to put more water down the outflow. More data needed :-).

 

for eg, the 50sqm garage looks like it has 100mm pipe but it runs out to the curb, so no effect from neighbours. the pipes where full up to the gutter and the gutter was overflowing badly. clearly just to much load for the pipes.

 

the grate on the road wasn't overflowing so i think the storm drain was coping ok, but the house was also over flowing. not just out the overflow, but over the gutters as well. each gutter goes into 100mm but not sure what size they feed into. it may have a 150mm to the storm pipes.

 

the problem of course is that overflow all ends up on my footpath and flows down to the garage.

 

if i put a tank on the back of the house, i can plumb an overflow that goes down the back section which goes into farmland/creek.


tweake

1300 posts

Uber Geek


  #3041984 25-Feb-2023 21:12
Send private message

Benoire: Look at smaf1/2 area requirements from the AC storm water code of practice along with the Auckland unitary plan, these will give a good idea of how much capacity you might need to actually do anything helpful.

 

i'll look at that but they will be doing it for a different reason. they would be wanting to hold a large amount and put less flow into the storm water than normal. where as i'm putting normal flow into storm water. just want to hold water if that gets pushed past max.  


MrBBEye
292 posts

Ultimate Geek

ID Verified

  #3041989 25-Feb-2023 21:58
Send private message

tweake:

 

anyone done this at all?

 

just looking at storm water detention tanks due to the rain which was to much water for the pipes to carry. a previous owner had tanks here, which have long since been removed. so i was thinking about reinstating that to handle excessive rain especially as these big rain events seam to be getting more common every year.

 

catch is what size would i need ?? 

 

 

Mine is more than 5000lts(1m wide x *** high) with a pump @ the bottom. It takes surface, spouting, backyard drainage water & run off from neighbouring properties. With heavy rain it takes ~30mins to fill if I turn the pump off(I never do) & will keep filling 2-3 days after. Cyclone Gabby was an exception. City storm water failed so place flooded but once city storm water was operational I had 7 days solid refill.


 1 | 2 | 3
View this topic in a long page with up to 500 replies per page Create new topic





News and reviews »

One New Zealand Extends 3G Switch-off Date
Posted 11-Apr-2024 08:56


Amazon Echo Hub Review
Posted 10-Apr-2024 18:57


Epson Launches New Versatile A4 Desktop Scanners
Posted 10-Apr-2024 15:31


Motorola Mobility Launches New Android Phones in New Zealand
Posted 10-Apr-2024 14:59


Logitech G Unveils the PRO X 60 Gaming Keyboard
Posted 9-Apr-2024 19:01


Logitech Unveils Signature Slim Keyboard and Combo
Posted 9-Apr-2024 13:33


ExpressVPN Launches Aircove Go Portable Router With Built-in VPN
Posted 26-Mar-2024 21:25


Shure MoveMic Review
Posted 25-Mar-2024 12:47


reMarkable 2 Launches at JB Hi-Fi New Zealand
Posted 20-Mar-2024 08:36


Samsung Galaxy S24 Ultra review
Posted 19-Mar-2024 11:37


Google Nest Wifi Pro Review
Posted 16-Mar-2024 11:28


Samsung Galaxy A55 5G and Galaxy A35 5G
Posted 12-Mar-2024 12:41


Cricut EasyPress Mini Zen Blue launches at Spotlight New Zealand
Posted 12-Mar-2024 12:32


Logitech Introduces MX Brio Webcam
Posted 12-Mar-2024 12:24


HP Unveils Broadest Consumer Portfolio of AI-Enhanced Laptops
Posted 3-Mar-2024 18:09









Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.







Backblaze unlimited backup