• David Spicer

Constructed Wetland

Updated: Jan 22, 2019


In May 2018 I was invited to work in Western Australia, which was quite the milestone for me, as it was the last state in Australia for me to say I’ve work nation wide in permaculture design and installation. It was meant to be a short trip only 5 days to repair a leaky dam seemed a bit odd for me to fly from the east coast to the west coast for this but as this is my only source of income I jumped at the chance.

So, I flew over dry hire the excavator and proceeded in the dam repair

Before and after the dam repair.






While I was doing the job, my client asked what could be done in the section below the dam, I recommended a constructed wetland based off Peter Andrews system of creating a chain of ponds in water courses, but this was a little different as it was down the side of a ridge and not in the natural water course.


To be truthful I wasn’t sure how I was going to do it, to complicate things more when I did some tests hole for the ponds there was no clay and the spillways would be on the walls of the ponds, something I’ve never done and something we teach never to do when talking about permaculture earthworks construction ( we never) place spillways on [un-original ground] meaning spillways should always be on original ground as they are stable and ideally covered in vegetation, there was a lot of iron stone rock, I think pushed out of the large dam above the dam I was working on, so I thought I could use this material to place on the spillways.

There was a earth berm created from the larger dam construction to steer the over flow down the side of the ridge which was clay.

So, in the end I had the makings of the system on site.

So I formed the pond shape and set the level sill spillway up by compacting as much as possible than excavated the clay out of the berm and did a clay liner in the pond to just above high water mark than re-applied the top soil.

As always there’s a first for everything and this was my first try at creating a chain of ponds or constructed wetland.

Below are a series of photos of the construction process




the finished product



If you want to see the finished product functioning please click the link for the video some 3 months after.