Rainwater collection

Discussion in 'Designing, building, making and powering your life' started by Pragmatist, Apr 25, 2013.

  1. Pragmatist

    Pragmatist Junior Member

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    Hi All,

    The landlords at our place here in Adelaide finally removed the rusted-out water tank from the 6mx6m shed. I can now install something that actually works so I can collect the rainwater for the garden. Having no experience in this, I'm looking for some advice from all the experts out there :)

    We're starting with guttering intact connected to a single outlet at about 2m from the ground (currently open to drop the water to the ground).

    My initial thought is to use 2-3 IBCs in a stack with the water flowing from the shed into the bottom tank(s) with a solar-powered transfer pump to fill the top tank to provide enough pressure head to water the garden.

    Before I buy the bits, any suggestions or advice to make something work?
     
  2. annette

    annette Junior Member

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    Buy stuff that you can take with you when you leave. Make sure you include it in your rental agreement. From what you have said you will be able to take it with you when you leave.

    Set up sounds good.
     
  3. Pragmatist

    Pragmatist Junior Member

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    The plan is to use something that can be rapidly broken down to move (and also scalable if it turns out to have insufficient capacity).

    I'm thinking of the following components to run it:

    https://www.gumtree.com.au/s-ad/dry...e-ibc-pallet-tanks-seconds-rejects/1017980992

    https://www.ebay.com.au/itm/12V-DC-...0PSI-Model-Brand-new-/110884229203#vi-content

    https://www.ebay.com.au/itm/NEW-10W.../270818161680?pt=AU_Solar&hash=item3f0e053410

    Does anyone have any experience with IBC-based water storage systems to tell me if I'm on the right track?
     
  4. Terra

    Terra Moderator

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    System sounds good , cover the IBCs to keep light out or you will have algae problems .

    Look at automatic Bilge pumps or Bilge pump and float switch these will move water a lot quicker while its raining . Brushless Water Circulation Pumps are used for moveing hot water around some will run straight of a solar panel .

    I use them in aquaponic systems and find them light and easy to work with .
     
  5. Pragmatist

    Pragmatist Junior Member

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    Thanks Terra,

    Thanks for the tip on covering the tanks - I'll be sure to do that.

    I'm not too worried about shifting water around in a hurry. The top tank just needs to have enough water in it to water the ~60sqm garden so low pumping rates should cover it. The pump can move water slowly during the day and then I take the water in one hit to water the garden.

    Solar panels are not very effective during Adelaide rain events and I'd rather not have the complexity of a battery in the system. The basic idea is that the top tank refills during the summer months when I need the water. At full speed (which would need a larger solar panel to support and likely exceeds the duty cycle of the pump) the linked pump will fill a 1000l tank in a bit over 4 hours (pretty reliable sunshine during our summer) and I won't have the storage to use that much water each day in the garden, even if I wanted to do so.

    My basic plan is the the rain fills the lower tank(s), which have a capacity of ~1000l each, which represents about 30mm of rainfall. Actually, I just calculated that and it indicates that I will probably need quite a few more tanks to catch all the winter rain off that 36sqm roof. According to Adelaide data, I'll need about 14 tanks to store the mean April-September rainfall. That assumes that all the rain ends up in the tank, which will certainly not be true for light showers for which the evaporation is high. I might also want to run a diversion system to minimise the crud getting into the tanks and fouling the pump.

    I'm trying to keep the cost and complexity to a minimum so I might start with 3 tanks and then grow the system if the rainfall justifies it and I have the time to do so. There is enough space around the back of the shed now to fit about 4x2 tanks so that's 16 tanks at 2 deep so space isn't a problem (for once :))
     
  6. Pragmatist

    Pragmatist Junior Member

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    The solar panel turned up today (60W, ~$110 delivered from eBay) so I'm just waiting for the pump and a chance to pick up the tanks and I can start testing and building :)

    Will update with photos when it gets further along. So far it looks like this:
    View attachment 1607
     
  7. Pragmatist

    Pragmatist Junior Member

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    Finally got out to pick up the IBC tanks (got 4 for about $200) and the pump turned up. Hopefully I get a chance to do something with them on the weekend.

    View attachment 1612

    The pump could be interesting. it was sold as having 1/2"/10mm barbed fittings. Turns out that they are 10mm rather than 1/2" and have minimal barbs. I might need some trickery to connect it in to a 13mm poly pipe in a way that will withstand the 80psi output pressure. Any suggestions?
     
  8. 9anda1f

    9anda1f Administrator Staff Member

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    Well, if I read your plan correctly, you're not pressurizing the upper tank (only using the pump for transfer) and so should not ever see 80 psi at the fittings. This will help some. The pic doesn't show the fittings (they're capped with red covers) but in the states we have clear "Trygon" tubing that's quite strong but flexible enough to be used as an adapter between sizes in many cases. I might also use a loop clamp (radiator type screw clamp) for insurance.
    https://www.usplastic.com/catalog/default.aspx?catid=864
     
  9. Pragmatist

    Pragmatist Junior Member

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    Thanks 9anda1f. I'm going shopping for bits now so I'll see what options are there.

    The covered photos led me to make a slight leap of faith (low risk at such a low price)
     
  10. Pragmatist

    Pragmatist Junior Member

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    Rainwater harvesting.

    Laziness and missing the rain got the better of me so I'm starting the system without washing out the tanks properly so a cold-water soak will have to do. With a few filters around the pipes, it should sort itself out into one of three categories pretty quickly in use:

    • water soluble (eventually)
    • comes off as lumps and caught by filters
    • stuck on the inside for good.
    As we're not drinking the water, I'm happy enough that the risk posed by watering the garden with dilute water-based glue (the last thing in the tanks) is suitably low.


    The size thing forced a slight redesign. The dimensions of the tanks are 1.1m high, 1.0m wide and 1.2m from tap to opposite wall. This means that I can only fit a single row behind the shed while maintaining access to the taps. No big deal for now as this gives room for 12 tanks (at 2 high) if I move the worm farms and we're not likely to have so many tanks very soon. There is more space around the side of the shed if required anyway.


    The extra height of the tanks (1.1m instead of the 1.0m I had expected) puts the top of the second layer at or slightly above the height of the gutters. This means I'll have to drop the water into the bottom layer and pump it up from there.


    The extra height also puts a 3rd layer 30cm (12") higher than I had planned and it would protrude above the shed height, even in the centre of the A-frame roof. I'll have to check with the neighbours and council rules to make sure it's not going to upset anybody before putting up the 3rd tank. I may end up having to make do with the lower pressure head of just layer 2.



    The cheap wooden-based IBCs (I got two of those and two steel-based) have a plank of wood right across the centre so blocking access to the top hole of the next layer down. I had planned to use these for upper layers for cost reasons but might need to use all steel-based containers as these give centre clearance.


    Still learning as I go :)
     
  11. Pragmatist

    Pragmatist Junior Member

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    The tanks out the back of the shed showing:

    • the total height just exceeding the gutter height (so I have to dump into the bottom layey, not the top layer)
    • the lack of space for a second row between the shed and the back fence
    • The likely height above the shed roof that a third level would protrude.
    (The mess in the foreground is a mulch/compost pile of old pumpkin vines with shredded paper scattered on top)

    View attachment 1615

    I'm pretty sure I have a workable plan but any ideas are gratefully accepted :think:
     

    Attached Files:

  12. Pragmatist

    Pragmatist Junior Member

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    Keeping out the light

    OK, the tanks are somewhat in place (still need to buy and install a few more) and there is water in there thanks to some recent rain.

    Now I need to cover them to keep out the light. Before I go the plastic weedmat option (builders plastic is more expensive, more delicate and less UV-stable) what other options are there? I have no particular hassle with used plastic drums but new plastic sheeting seems a bit non-permie for my taste if there is a better option out there.

    Any suggestions?
     
  13. eco4560

    eco4560 New Member

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    Weave something out of willow or bamboo or whatever you have locally?
     
  14. Pragmatist

    Pragmatist Junior Member

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    I thought about letting something climb over the framework but the trouble with anything climbing or woven is that the light exclusion is partial (at best) so probably wouldn't actually stop the algal growth :(

    I'm happy to be corrected on this assumption.
     
  15. eco4560

    eco4560 New Member

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    I just had a vision of a wattle and daub panel around the outside of it with a wooden lid that you could lift off when you need to access it. That would be fun to make but perhaps not so practical....
     
  16. Pragmatist

    Pragmatist Junior Member

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    It would be great fun to make but the pile of tanks I will end up with is ~3.5m high so that would take a lot of time and materials (which I don't have, living in suburbia and all...)

    As an engineering task, it would be interesting to see how rigid and heavy a panel of that size would be and whether it could withstand rain and wind loading.
     
  17. Terra

    Terra Moderator

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    Many options , scratch around in the aquaponic world for photos i have a few but i cant remember whos they are so dont feel i can repost them , all sorts of recycle neat covers , fit timber to the cage and cover with recycled pallet timber or wrap corrugated iron around and screw to the timber frame , or just use dark paint (doesnt stick very well ) , small bundles of bamboo lashed neatly to the sides , pallet cover sheets (eg between cement bags and the wooden pallet to stop tears ) all sorts of gear availiable that is thrown away check out hardware stores ect they have to pay to get rid of this sort of thing . Do you have dump shops where you are (cheap recycle stuff )

    Rob
     
  18. Pragmatist

    Pragmatist Junior Member

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    Thanks for that. Unfortunately there are no such shops in my local area :( and it would take considerable time and fuel to get to such places. I might just go for the weedmat idea for now just to get it working and to avoid the algae. As I work out a better solution down the track I can repurpose the weedmat for various other screening purposes.

    Not ideal but this whole thing is a bit of a compromise in our situation.
     

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