Swale below septic trench - pond nutrient???

Discussion in 'Designing, building, making and powering your life' started by stevereed, May 4, 2008.

  1. stevereed

    stevereed Junior Member

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    Hello

    I'mn in the process of planning some swale placement on my 4 1/2 acre block of land in Armidale NSW. I am looking to redefine my access drive on contour (for as much as is practicable), with a swale below it - connecting to a large aquaculture pond, the swales acting as an overflow system for the pond , water overflowing downhill via a spillway to another swale (PRI's Water Harvesting DVD providing some great tips as to multi functionality).

    The big question is this - my swale which will be connected to the pond will run on contour just below my septic trench. To me it seems like a good idea - some nutrient to feed the pond system which will include freshwater prawns and mussels if I can get some which suit this climate, and eventually fish. I'm concerned about excess nutrient entering the pond and the formation of algal blooms which are bad for my system.

    The nutrient from the septic trench obviously leaches into the subsoil downhill naturally, but what if it leaches into my swale and then some enters the pond system?????

    any info or advice on this would be helpful. The extra nutrient seems like a resource worth utilising but I don't want it to have a negative bearing on the aquaculture or indeed my health.

    Cheers

    Steve
     
  2. gardenlen

    gardenlen Group for banned users

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    Re: Swale below septic trench - pond nutrient???

    dunno steve?

    might be difficult to control nutrient imput which could be variable from little to none to too much and then as you say you end up with algae blooms to deal with or an over population of water plants to the degree of clogging all of the pond/dam, but if you can ahrvest that excess that would be good for compost on the gardens or around food trees. most ponds/dame get enough nutrient from rainwater run off as it is i would suggest.

    maybe have a swale below the septic field but only to put any top flow back into the sub soil. also might be a good place below the leach field to plant the food trees? and you can of course grow veges ontop of the leach field (think there is a link to this on our site), not suggesting root crops but all your above ground fruit and leaf vege's, after all why let the grass enjoy all that nutrient benefit?

    driveways can be difficult to do but so long as you are along the contour as much as possible you should be able to design some control in for those high rain periods water run off.

    len
     
  3. ho-hum

    ho-hum New Member

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    Re: Swale below septic trench - pond nutrient???

    Steve,

    You have answered your own question......'The big question is this - my swale which will be connected to the pond will run on contour just below my septic trench.'

    Swales don't have a mindset, they just move their inputs downhill.

    cheers,
     
  4. stevereed

    stevereed Junior Member

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    Re: Swale below septic trench - pond nutrient???

    Thanks for the inout Len.

    On the other post.........my question wasn't will the swale pick up nutrient from the leach field, that's obvious. BUT is it sensible to put a swale in a few metres below the leach field with the uptake of nutrient feeding into my pond?

    Other obtions could include running that part of the swale downhill slightly (as a diversion drain) which will feed the next downhill swale unconnected to the pond with the benefits of the septic nutrients feeding the downhill swale bank and subsoil. A nice idea, but if the septic nutrient would be of real benefit to my aquaculture system, feeding prawn and mussels etc then it's worth doing. Just looking tto see if there appear to be any significant negatives to going down this route

    Cheers
     
  5. SueinWA

    SueinWA Junior Member

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    Re: Swale below septic trench - pond nutrient???

    I'm no expert in such things, but using the nitrogen from the septic to feed the pond seems to be begging for trouble... trouble that might well be a real mess to correct later. You won't be able to control the nutrient load going into the pond, and you would probably get a massive algae bloom that would only get worse. If you only use fish waste as a nutrient, at least you could control that by adding or removing fish.

    I think Len has the best idea: planting downslope from the leach field, and keeping any diversion between pond and septic separate.

    Sue
     
  6. stevereed

    stevereed Junior Member

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    Re: Swale below septic trench - pond nutrient???

    Yep, I think that I will keep them separate.

    I'll certainly plant below the leach trench but may do one of two things in relation to the swale.

    1. Run the wsale accros the width of the block and incorporate it into the pond, but before we reach the leach field, drop the ditch slightly off contour into more of a diversion trench to allow excess nutrient to run slightly downhill and away from my contour swale.

    OR

    Stop my swale 4 metres short of the leach field, leave a gap and start a second contour swale below the leach trench but not connected to the one feeding my pond. I can utilise the gap between swales as my vehicular access to the rest of the paddock.

    Thanks for the input everyone

    Cheers

    Steve
     

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