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Hi as you can see i am in Perth. Didn't know what a soak well was until I moved here.
One of my downpipes needs a soak well installed. (I think) Is it as simple as just digging a hole and placing the soak well in the hole and connecting the down pipe to it?
Anyone got any tips?
What is better plastic of Conrete?
How do you work out the size needed? (this must depend on rainfall, roof catchment size, & ???)
thanks
paul
G'day Paul
Welcome to WA - the world's biggest sandpit! You say that one of your downpipes needs a soakwell installed. The normal position in Perth is that all of your downpipes would need a soakwell. Is this just one that has been left out when the house was built and all the others have them?
To answer some of your questions:-
It is that simple - yes. Dig the hole, place the soakwell in it, connect the downpipe (you can buy all the relevant fittings from hardware stores), place a paving slab on top and bury the whole lot in sand. You've probably noticed that supply of sand won't be a problem!
Plastic downpipes are normally adequate. Shop around a bit. You'll find that different outlets (even Bunnies!) offer deals on soakwell plus paving slab for around $20 -$25. (The concrete soakwells are stronger but, frankly, they're not placed under great stress, being circular and buried in sand, the plastic ones do the job).
They tend to come in a standard size. You need one for every downpipe. You're right about the roof catchment size etc. This determines the number of downpipes required. I don't have the formula immediately available but I've got it buried somewhere amongst some paperwork. If I can find it, I'll post it later on.
We do tend to get some fierce rainstorms in Perth. When they happen, your downpipes and soakwells won't cope. I've seen water spewing back out of the connection up to a foot high. In those conditions, no soakwell will cope. This means you need to be careful about the positioning. It's not a good idea to place one anywhere close to a doorway unless the door's threshold is significantly higher than the point where the downpipe disappears below ground level.
Hope this helps.
Col
Just out of interest's sake, do all downpipes go into soakwells over there? Are you not allowed to run stormwater pipes out to the road gutters? This soakwell business definitely wouldn't work here, we had over a metre of rain week before last.
Mick
Paul.
DAMHIK.
Calculate the total volume of the soakwell you need (the suppliers have info as the that) then double it.
Paddling in 50 mm of water across the verandah to get to the garage and sweeping 25 mm of water out of the workshop makes you realise that the soakwells really aren't too expensive.
Mick.
Where I live, in Albany WA, it is illegal to run water from the roof into street drains or sewers. Mind you, 1000 mm is more than the average rainfall per annum down here.
Thanks Col, Robert
The house we moved into 2 years ago has some soak wells but not on all the down pipes.
Robert excuse my ignorance but what does DAMHIK mean/stand for?
Col, My first thought was to go for concrete, but that may just be my civil engineering training, If they were pretty close to the surface and weren't too tall, plastic would be ok, but are they prone to collapsing?
Paul
Paul.
"Don't ask me how I know."
Paul
The plastic soakwells I installed in my place 16 years ago haven't collapsed and I don't expect that they will. As I said, they are circular in section and they are supported all round their perimeter by sand. This makes the completed structure pretty strong. I was trained as a structural engineer, incidentally. That explains my confidence in plastic structures - just as your training as a civil engineer explains your leaning towards concrete. (For the non-engineers I should tell you that there are a couple of really bad engineer's in-jokes in that lot!)
You know what they say - any idiot can design a bridge that works. The trick is to design one that only just works!
If you bury the soakwells so that the paving slab top is about 450mm below the surface in pedestrian-traffic only areas you really shouldn't have a problem.
Mick - what Robert says about running stormwater into roads and sewers applies all over WA. In this very dry place, the smart thing to do would be to plumb it all into rainwater storage tanks, of course. That's what happens in the bush but we spoiled townies don't do it so we let a lot of good quality water go to waste. I reckon that water restrictions are going to become a permanent feature of life in Perth sooner rather than later. That's when we'll have to seriously re-consider the issue of collecting rainwater.
Col
Paul
There can be a bit more to this topic than you probably imagined and it is right up my ally, well kinda sort of anyway.
DAMHIK either! Well okay, a townhouse I had built flooded a couple of years ago because the soak wells were inadequate! The tenant was not impressed! :mad:
So before fixing the problem I did some research. I am also in the process of replacing the slotted drain (or ag-pipe or whatever the crap is called - I WOULDN'T EVEN THINK ABOUT USING IT) that was used in my current house with concrete soak wells. There is some info from some of the councils which can be easily found by looking up "soak wells in WA" on Google.
Suppliers generally advised 1 x 600mm X 600mm soak well per downpipe. I prefer the more scientific approach (as recommended by the councils) which is 1 cubic metre of soak well per 65-80 square metres of catchment or 12.5 litres of soak well per square metre of catchment. I try to position them at least 1.5m away from the house or other structures.
All the other advice from Col and Robert is spot-on except I disagree with using plastic. Now just to add to the engineer bit, I'm a Mining Engineer so I'm used to digging holes in the ground - although not in sand! I have heard of plenty of plastic soak wells collapsing and for the slight cost saving I won't touch them. If you shop around concrete is not much more expensive.
Couple of other points:
I have a big block with vehicle access all round so I use heavy duty (or traffic) concrete lids in any position they are likely to have vehicles run over them.
Also, I backfill around the soak well with blue metal - which increases their capacity and helps stop sand washing back in to them.
Probably more than you wanted to know - but I have been burnt once so now I do them properly.
Good luck
Geoff:)
Just wondering what the reasoning is behind the use of soak wells rather than discharging to the gutters which eventually feed into stormwater drains/creeks/rivers/ocean. Urban development tends to stuff up the environment pretty big time but I think that having stormwater take as natural a path as possible would be better for the environment. I release that this may not have been in the forefront of people's minds when these laws were written. I'm also guessing that perhaps over there there aren't too may natural watercourses and that when it rains (which isn't that often by the sounds of things) water just tends to lie where it falls before soaking into the ground. But surely there must be some areas that have soil types that are not so well drained. If you are situated right next to a natural watercourse are you still not allowed to discharge stormwater into it, even though that's where the water would end up if your house roof was not there to catch it? And wouldn't it make more sense to have a single large rubble drain fed by all the downpipes (not thinking for one moment that laws always have to make sense).
Puzzled:confused: :confused:
Mick
Mick.
You have asked a question that derives from logic and common sense. That is entirely the wrong way to approach matters of government in WA.
The answer to the question is, probably, that it was the way things were 150 years ago and one must not make hasty changes.
Having said that, why would anyone live anywhere else than in WA?
Mick,
I would have thought that a soakwell would be a more natural path given the reasons you stated yourself.
If the house were not there, the water would soak directly into the ground. Surely the next best approximation with a house would be to distribute the water about the house dumping into soak wells spread about it?
Using stormwater pipes, ultimately feeding directly into creeks is definately not natural. I take witness to the storms in Melbourne before Christmas where usual calm creeks were turned into raging torrents, rising some 6+ metres simply due to the direct feed of storm water into these creeks. The evidence of these flood waters is still present along parts of the Merri Creek bicycle path around Bell Street area.
But Perth is so sandy that yes it is hard to believe there is any natural water courses as water literally just disappears from the surface directly down!
These soak wells are simply a sandy bottom which the water soaks into, not a massive bore directly into the water table, which is another thing over on Perth where the water is lifted up through bores for gardens - now that causes problems as the water table becomes depleted...
Mick
Reckon also, as with most things, it probably comes down largely to a cost thing.
As mentioned Perth tends to be sandy and has little in the way of natural watercourses etc. Local councils already have to take care of the stormwater runoff from roads etc for which they generally build ugly big surface soaks. So, when it comes to private land the easiest and cheapest thing is - "all stormwater must be contained within that land". How easy and cheap is that!:p
Oh, don't worry about the fact that they created a high density housing area zoned R60 where up to 75% of the block can be covered by buildings. I reckon it is almost physically impossible to dispose of 100% of your stormwater in less than 25% of the land area during some of the heavy storms we get. Net result - someone gets wet! :mad:
Geoff
Ray,
Actually round here discharging to a watercourse is more natural but then it's a matter of soil types and rainfall. I'm right near the river and on the only bit of non clay soil for miles around (alluvial silt) but up here almost everywhere is clay. Even after months of rain you can dig down a few inches and it's bone dry. So when you get 150mm of rainfall in two hours it just finds the most direct path to the nearest watercourse. During a recent deluge (over 1M in a week) I had a stream of water over a metre wide and about 200mm deep running down the middle of my yard. So it looks like our respective local legislators are perhaps not that silly and are tailoring laws to suit conditions.
Mick
:DQuote:
Originally posted by PaulS
Hi as you can see i am in Perth. Didn't know what a soak well was until I moved here.
One of my downpipes needs a soak well installed. (I think) Is it as simple as just digging a hole and placing the soak well in the hole and connecting the down pipe to it?
More or less javascript:smilie(':D')
Anyone got any tips?
Yes dig the hole at least 200mm larger in diameter than the soakwell. Place the soakwell in the middle of the hole and fill the surrounding 100mm space with bluemetal. This improves the efficiency of the soakwell and helps prevent any sand from being "washed in" by the water leeching out. Place at least 50mm of bluemetal in the bottom of the soakwell again for efficiency, it helps soak the water over a larger area instead of it just forming a dip in the path of the water flow.
What is better plastic of Conrete?
I prefer concrete - partly just a psychological thing - though a necessity if the area is to be driven over.
How do you work out the size needed? (this must depend on rainfall, roof catchment size, & ???)
There probably is a formula but in general you can't really go too big. I'd start with a 900mm unit myself, though your circumstances may justify more and smaller units.
thanks
paul
Regards
Peter
Thanks for all your help
Now comes the hard work or digging the hole, lucky its just sand! Although there are sewer pipes (and other services, phone, electricity... now that i think about it) going past where it must go which may complicate things a little.
I’ve installed many a soak well in Perth sand, I always use concrete as they are much easier to dig in.
Establish the spot were you want it, clear any lawn etc away put the soak well on the sand and dig the sand out of the inside of the soak well and it will gradually sink in.
Means you dig about half the quantity of the sand out I reckon.
The blue metal has merit but for the extra effort required i'm not sure it's worth it. the side holes on concrete soaks point at an angle down this is (in theory) to stop the sand washing in.
Cheers
Dave
Davo,
i would never have thought to do it that way, but anything to do a bit less digging has to be good.
Paul
From information gathered by speaking to people who live in bushfire prone areas in NSW it is now law that when building new houses that they must have an underground storage pit of at least 20000 litres.No rainwater can be discharged into gutters as well. apart from this they must have stainless steel insect screening on windows there must be a cleared area of at least sixty metres around the house etc etc
Could this be the way of the future ?
What a good idea, you would not be reliant on draining dams, as at present ,when you want to water your garden,wash your car,etc
HiQuote:
Originally posted by PaulS
Davo,
i would never have thought to do it that way, but anything to do a bit less digging has to be good.
Paul
Keep in mind though, that it is a little awkward digging inside the soakwell. Your movements are somewhat restricted when you are about halfway down.
Regards
Peter
Peter,
Having restricted movement might be a good thing, it might be a good arguement to get my wife to dig the hole..
Paul
Paul
Let me know if you have any success - I have tried many times but SWMBO just won't be in it!:rolleyes:
Geoff
yes does get a little restricted in the hole, equip the missus with a post hole shovel that’s the tool for the job I’ve found.
Cheers
Dave
I came across this page with an extremely handy calculator applet for downpipes thanks to Ken Sutherland of Construction Hydraulic.
http://www.conhyd.com/DPcalc.html
Would anyone know where to download the AS 3500.3.2 "Stormwater Drainage - Acceptable Solutions" for free?
(So far only found https://www.standards.com.au/catalog...=stds000020843 which charges for the PDF download).
Paul,
While your in the digging mode it always pays, especially when you buy an established house, to dig up one or two of the soakwells that are near trees or bushes. About the only thing that can go wrong with them is they get choked with roots. All you do is dig up the lid and lift it. Use a steel rod to locate. Watch the gas, water, phone lines.
BTW when I use plastic I dig the hole with about a 50 mm gap around the outside and backfill this (gap) with bluemetal or clean gravel. Tends to stop the roots actually choking the soakwell itself, as well as the infilling discussed. Be accurate with your hole or the blue metal will cost more than the soakwell :D
BTW2 Paul DIG NOW after the rain, its much easier while the sand is damp. (use this argument with SWMBO)
Oh and for Mick
Here's my front yard - see plenty sand mate, drains good and soakwells are cheap. Also good for mixing up some mud - free yellow sand on site.:)
My house is lower than the road so no storm drains available unless I go about 110 metres through two other houses, and its a no no. In the photo (you can't see it) but there is a soakwell on the corner of the house.
squizz,
Having put that post a few months ago, do you think I have done anything yet?
No I haven't! You know what they say, i am still in the planning process.
One of these days i will get around to doing it. But i fear that now we are in August, and in a couple of months there will be no more rain, it might be a job that gets rescheduled if you know what i mean. And anyway the timber is coming up, so we must get our priorities right.
Paul
Paul, You can't rush into these things Mate. Well done but you really need to do a bit more planning. Its taken me 3 years to plan the front yard:D and I've only got stuck into that because if its all dug up I don't have to mow it.
Cheers
Does anyone know what to do when a soakwell is permanently overflowing even when there is only little rain? We have that problem at our rental place and the tenants aren't impressed as there is always(after rain) a little lake in front of the main entry.
That house is in Mindarie WA and it seems the soil is not draining the water away fast enough. Sometimes the little lake stays there for another two days after the rain stoped. I am not an expert but the soil looks like a lime stone sand mixture.
Our tenants are moving out soon and then I'm planing to dig the soakwell up to see if there is anything wrong with it. If not then the problem must be the soil and I would like to know what to do before the next tenants moving in.
There are only a couple roses near by, so I don't think root are the problem.
Any help would be greatly appreciated.
jsandso
jsando, if its not roots then it will be one of two things:
1. A blockage in the drain pipe which runs from the bottom of the downpipe to the soakwell, or
2. The soakwell has collaspsed or is full of sand.
I'm afraid its a matter of digging the soakwell up and having a look. Being in Mindarie I assuming its not that old so it could be a plastic soakwell and these will collaspse if any considerable weight is put on them.
Cheers
I agree with Squizzy dig the b**tard up. I've dug a few in the Mindarie area and can attest to the soil being lime stony. This reduces the drainage but doesn’t usually cause such an extreme overflow problem.
It really is worth a look though as it could have caved in, or as in one similar case the naughty builder hadn't actually put one in at all, just a pipe going into the sand. I guess the ground was too hard and it was beer time late on a Friday or something.
If the soak well is as it should be and the pipe isn't blocked you may need to dig another soak well beside it and connect the two.
Cheers
Dave
Thanks guys,
looks like I have to dig the soakwell up to find out whats causing the problem.
I would not be surprised not to find a soakwell at all, as the builder also "forgot" to connect a waste pipe to the sewerage and the waste water was just draining away into the ground.:mad:
I'll let you know.
Thanks again for your time and help.
jsandso
jsandso,
Just another quick tip (now that this topic's back up the top again). If your connections between downpipe and soakwell are complete, make a notch in the topside of the lowest bend, just above ground level. This stops water backing up and doing either one of two things - blowing the downpipe out of the soakwell connection, or blowing back up to the gutter and flooding your eaves. Learnt this one the hard way after making the whole connection air-tight, and watching the whole thing fill up to the gutter level. :eek: That notch at the bottom allows the overflow to be dispersed at a lower level, while having it at the top of the pipe means that the water coming down still goes into the soakwell.
Lessons learnt at school were a lot cheaper than the ones I make around my house :o
Craig
If you do dig it up, then I recommend you put a layer of coarse bluemetal at the bottom of the hole and completely around the outside about 75-100mm in thickness. The bluemetal makes a tremendous difference to the dispersion of water OUT of the soakwell. It allows ALL of the surrounding sand (or whatever) to absorb the water instead of the water soaking only into the areas immediately next to the soakwell holes.Quote:
Originally Posted by jsandso
Using this method (advised many years ago by my bricklayer dad) I have NEVER had ANY of my soakwells overflow :D
I haven't read all the replies but didn't see that anyone had written that you need to be at least 1500mm from the house slab and fence line??....I had to install 6 soakwells at a new house i built in Perth and had to run a line 7metres to a soak well due to lack of space...check with council.....the best soakwells I found were old plastic 44 gallon drums very strong and deeper than the standard bunnings ones.....I got my mates around and put on a BBQ and got them all done in 2-3 hours....cost me alot in beer though.....I never had any problems with sinking or collapsing...I watered in the sand which helped compact it after they were installed...Good luck
Thanks to everyone for your help, but unfortunately even after installing a second soakwell, next to the existing one I got a phone call from my tenants today that there is again a big lake in the entry area. Apparently the water was even flowing into the garage.
The soakwells are all installed correctly with gravel around and at the bottom of them. But I can tell you that I do not want to install another one myself. It toke me almost 5 hours to dig that hole. I had to use hammer and chisel to crash the limestone rocks. I think the condition of the soil in this area is just not suitable for soakwells. Especially with so much rain we had the last couple of days.<O:p</O:p
I rang a drainage guy this afternoon and he said that I have to add as many soakwells as it takes to solve that problem, that’s all he can suggest. I asked him if one of this drainage pipes from Bunnings or so could help to redirect the water to the other side of the lawn area, but he said this is all crap and the only thing is adding soakwells.<O:p</O:p
I just don't think this going to work on this water repellent soil.<O:p</O:p
Does anyone have any ideas how to fix this problem?<O:p</O:p
jsandso<O:p</O:p
Quote:
Originally Posted by jsandso
There really is not much you can do, other than what you are doing already.
There could be a *lttle* to be gained by perhaps a larger soakwell, however this becomes a more difficult task in the area in which you require soakwells.
It seems, from what you describe, that the problem is not so much the soakwell or the quantity of soakwells (in a specific location) but the surrounding ground material.
Obviously, as you can already appreciate, the water is NOT going to drain quickly through limestone. Your soakwell area is described as having sufficient limestone to make it a challenge to install the soakwells.
The ground under and around the soakwell is going to make the whole process difficult.
In *nromal* circumstances :D the house designers have to comply with regulations and have x number of downpipes for x length of gutter. A 1mtr x 1mtr soakwell (properly installed) at each of these downpipes (in my experience) in sandy soils will cater easily for rain runoff.
If you have a particularly awkward roof design that has a high runoff into a single or limited outflow, then yes you may need more or larger soakwells.
OF COURSE you can use stormwater pipes to move the soakwell to a more suitable location (or add more soakwells). "Drainage" pipes are something else - they are perforated to allow water to soak through and are not meant for this application.
Make sure though that if you DO extend the downpipe to a "remote" soakwell, that the extension pipe has a "fall" ie ensure that the water WILL naturally flow toward the soakwell.
You cannot keep adding soakwells to an area that does not provide suffficient drainage. You will need to obtain a more suitable area or perhaps consider redirecting the current "overflow problem" to a spoon drain to let the water flow over the ground area and ultimately drain "naturally".
hi
just looking into this stormwater/soakwell thing as we are about to do an extension and came across this page while searching - the regulations appear to be some sort of state secret to be kept from the general public at all costs
have discovered so far that in perth, one downpipe is reqd to approx 37 sq m of roof, and that one cu m of soakwell is reqd for evry 80 s qm of roof. in other words .5 cu m per downpipe or 1 cu m for two downpipes.
by the way, those plastic 600mm things have a capacity of .16 cu m, which serves about 13 sqm of roof or about half the roof area to one downpipe. ie they sound a complete waste of time.
what i cant find is the distance soakwells must be from house or boundary, something which reno8ter refers to above. if it is 1500mm, which seems reasonable, that would rule out any soakwells dowmn the side of a house with a setback of 3.6m or less, which is most sides of houses. this would mean joining all the downpipes down that side of the house together via a stormwater pipe and tarnsferring the water to the back of the block, by which time one enormous (1800mm) soakwell would be reqd concentrating the water in one place instead of spreading it around.
it also means you would have to find an area 4.8m across untroubled by buildings, boundaries, pools or trees, something that is not that easy to do even on a quarter acre block.
so please, can anybody tell me what the rules are for perth for soakwell distances from stuff, or tell me where to look it up?
thanks
G,day, 2 metres (in general) is how far away they should be from a footing. Hard and fast goes out the window due to a factor know as "Council Building Regulations". These seem to vary somewhat from place to place:rolleyes: .
The 600mm things are practically useless as you suggest. 12 to 14m2 per 600mm useless thing is what most new houses have. We generally try and talk the homeowner into putting in 1200dia x 1200h soakwells or even 1500 deep if there is no limestone sub-strata. Trafficable lids allow them to be placed under paving, driveways etc. I just finished putting a 1800 x 1800 (2 x 900 deep stacked) in a place in Fremantle. This was more than sufficient for the council on about 300m2 of roof. It was a sloping block so the owner could run all his downpipes into a 125mm drain and down to the soakwell at the front.
Just remember the bigger the soakwell the better but size and weight can be a problem for installation. We use a bobcat and 5 1/2 tonne excavator. The plastic piles of junk are dangerous if you ever want to drive into your yard or operate landscaping machinery.
Contact your council for the good oil cause I give up on what formula they are using this week:confused: .
Cheers
Hiya,
Would it be naive to suggest a rainwater tank? I guess it has to have an overflow anyway, though. Just a thought!helga
What Squizzy said.
This was what I managed to find out when I looked into it. About 2 meters from footings/slab and same from retaining walls.
Geoff