PDC…..Week 7

Half-way there and still much learning taking place.

This week we looked at water—fresh water, greywater and blackwater. Strategies for re-using greywater: regulate what goes down the sink (“only put down the sink what you’d be willing to put on your skin” [Wendy van Dok]; don’t store greywater for more than 24 hours—this is required by law—pathogenic bacteria can breed up if it is left for longer; avoid contact—by law, greywater can only be applied by sub-surface irrigation; be aware of quantities—the most common problem in using greywater is waterlogging. Share it around, don’t leave it running on the same area for weeks. All common sense really.

Greywater treatment systems can be an expensive option. Far better is to create an artificial wetland—a reed bed system. Bacteria on the roots of the reeds filter the greywater and the reeds can be regularly cut for mulch or compost. Greywater mulch pits are even better—greywater is diverted into a slotted drainage pipe which is placed inside  a hole filled with mulch. The mulch eventually rots down and can be placed around fruit trees and the pit refilled with fresh mulch. The idea I liked was that a long narrow hole filled with mulch can double as a pathway.

Good link here.

The easiest way to deal with blackwater is to install a composting toilet. We discussed various types. The best resource for this is the Humanure Handbook, which is now online.

Finally we looked at collecting and storing fresh water; the 3 S’s: slow, store & soak. Don’t let good water run off a property; slow it down, store it and let it soak into the soil. We looked at tanks (make them multifunctional—use a tank to screen out neighbours, or grow a passionfruit over it). Swales—level trenches dug on contour—can intercept water running over the land and store it so it leaches slowly into the soil. We learned to mark out the contours using three pieces of equipment—an ‘A’ frame, a length of plastic tubing filled with water and attached to a couple of measuring posts (called a ‘bunyip’) and  (the most sophisticated of all) a laser level. This bit of practical work out in the property’s sloping driveway, caused much hilarity, not to mention enjoyment, as we checked our measurements with A frame and bunyip against the laser level and found them spot on.

We looked at building various types of dams—constructing, maintaining and fixing leaks. We went into (not literally) natural swimming pools and wetlands, french drains and rainwater gardens, basins and erosion prevention. There was just too much to go into here.

I had previously thought the day we spent on soil was the most fascinating, but this one on water just boggled the mind. All the way home in the car, my brain hummed with ideas.


3 Responses to “PDC…..Week 7”

  1. rabidlittlehippy Says:

    This is the area I think I am going to end up getting bogged down in. 😉 Heavy cracking clay soil is not conducive to water leaching away. 😦 Hence raised Hugelkultur beds and swales are exactly what we need. However, I need to learn me about this contour business a lot more. 🙂


    • foodnstuff Says:

      You could try scattering gypsum to help break up the clay. It doesn’t affect the pH.


      • rabidlittlehippy Says:

        I am thinking I will have to. I’ve been advised by a few people to do so and now that I’m planning some heavy duty planting, as opposed to raised bed planting, I think gypsum and I will become good friends. 🙂


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