Geoff’s 800 square meter pond is shaped like a soup plate with a perfectly flat 2m deep bottom, ideal for growing out fish of all types.
This particular pond was allowed to mature and develop. Consequently, it was overgrown with weeds and grass. To clean out the system, Geoff decided to drain the pond partially so he can use cows to graze right down to the water’s edge. He then moves them off a few days later, when the task is complete. A lot of people have read about soil compaction caused by over-grazing by cattle and sheep, turning the soft soil into a hard concrete pan and resulting in soil erosion and land degradation. People balk at using animals near a water system these days. But here, Geoff uses the cows and horses to quickly blitz the water’s edge before moving them away.
Shocking the system with animal nutrient and pocketing the landscape, briefly, with their aerated hoof prints, captures water in a rain event and soaks it deep into the system along with their nutrient. It’s all part of the permaculture design process. Multiple functions with a diversity of added benefits.
Geoff uses a 12-volt solar panel to power a pump hooked up to a battery to trickle water over a 250-litre blue drum filled with gravel to add a little extra aeration to the pond over the summer period. It’s not absolutely necessary, but in a heavily stocked system, it’s a wise investment to guarantee dissolved oxygen in the water. Dissolved oxygen drains off faster as the water temperature rises. The cooler the temps, the more oxygen your pond is able to support.
The other innovation was a purpose-built smaller pond, adjacent the main pond and used to optionally feed the fish and capture them with a sluice gate, ready for harvest. If that’s not enough, growing food on a bamboo raft is another innovation Geoff designed that also acts as a floating small fish refuge system. Then there are the solar panel lights on the raft to attract insects at night to act as a source of extra fish food.
Now you know why Geoff Lawton heads the Permaculture Research Institute. All this stuff gets tested on his farm to see what works and what doesn’t.
Watch the video below to get all the details.
Has any one used any wind powered compressors or other devices to do the aeration in the fish trap? Not as reliable as soiar but might help with the base load oxygen levels ?
If you have wind your pond is already oxygenated is the issue, if you have a very sheltered pond very close to a very windy spot then it works, but that is a rare situation. Water flow through works if you have surplus water up hill or mechanical agitation if you have free mechanical power.
As for the extra oxygenation provided by the barrel o’gravel does this work because the surface area of the water increases massively as it flows over and around the gravel?
Has anyone measured the increase in available oxygen in the little fish trap pond compared to the larger fish growing pond?
Finally does anyone have any thoughts on the efficacy of this device in making water quality better for fish production?
https://www.youtube.com/watch?v=3XaQ0N6w_dI
This video is narrated in German, can’t seem to find the English version.
Here’s the English version.
https://www.youtube.com/watch?v=bDITD7p8AZw
Bill,
Whilst using a vortex to add oxygen to water is interesting, it does not do anything to lower the ammonia levels in water. That is why Geoff is utilizing biological filtration by running the water through a gravel bed that has beneficial bacteria growing in it. This technique helps to establish a functioning nitrogen cycle. The water movement through the gravel bed also creates some turbulence to add oxygen to it. For more info on the nitrogen cycle see this link:-
https://www.bioconlabs.com/nitribactfacts.html
Hello Ben
Who said anything about lowering ammonia levels in water?
The barrel and the fish trap are designed to ‘lure’ fish in for harvest with the twin benefits (for the fish) of regular food and a small pool of extra oxygen, at least that is how I understood its purpose.
Oxygen exchange takes place at the waters surface so by trickling water over gravel the amount of available surface water in the small area should be noticeably increased which if contained within the small pond will be noticed by the fish. They do gather at the base of waterfalls for the same reason.
As for the nitrogen cycle the pond is balanced which is why Geoff waited three months before adding the fish so no extra biological filtration is required.
Could somebody explain why the pond has such a conventional form?
Wouldn’t it be more beneficial to maximize the edge by using a different shape as described in designers manual?
Have you found snakes much of an issue?
Yuriy the uniformed shape from my understanding is for ease of harvesting the fish of course more edge would mean more habitat but some times practicality has to over ride patterning, hope this helps.
Regards David
Geoff, since I did your PDC in 2004 I’ve been busy developing largescale and small scale floating islands for nutrient control. I like your kang kong island, a nice project. I’ve been installing floating wetlands and reedbed islands in fish ponds in China and Australia, often with wetland grasses, to take up excess ammonia that can build up in the pond. I’ve also grown rice on floating islands, similar to ancient rice culture. Kang kong will do a good job, and wetland species can be useful for adding significant biofilm surface area within the water to provide de-nitrification, the roots can grow down about 2 metres or more: check out http://www.aquabiofilter.com for more info and photos of projects
Synchronicity at work?
Just posted on this blog is a good article on Kang Kong
https://tcpermaculture.com/site/2014/01/29/permaculture-plants-water-spinach-kangkong/
Great vision for a healthy ecosystemic fish pond. I’ve also seen a great design that uses a fly-trap style insect attractor, using a brick soaked in rotten offal as a smell attractor to flies and such, with a one-way entrance, and the base open to the mouths of hungry fish, so insects can go in, but they can’t ever leave. I’ve also seen something similar that can trap rats to be used as fish food.
Perhaps a fish pond in combination with a Good Nature auto-reloading trap (goodnature.co.nz/) for rats could help turn a rodent problem into a protein source for hungry fish.
Geoff,
How much water evaporation are you experiencing in your pond? How much water are you having to add to keep the pond topped off? Living in Southern California its really dry and evaporation is a concern.
Hi, would it be possible to post a link for the video: from prairie to monoculture?
Hi Sinnceer,
This video?
https://www.youtube.com/watch?v=gzrXcIvExE0
If you could yoke the oxygenation of your pond(s) to a Trompe, or series of Trompes, I think you’d really have something. After being fascinated by Bill Mollison’s discussion of Trompes, I started digging, and believe me this stuff took a while to find, and only after going down a now deceased engineer’s pollution reclamation rabbit hole did I find anything remotely useful. These links give you the no-sh__ hands on how-to of how to build a working Trompe. Feel free to contact me for any other Trompe findings at [email protected]. Yes… Old McDonald almost has his farm… in the North Carolina mountains, 2600 feet elevation… “(Ei)2 O Farm” will be the name soon, replacing Green Hill Farm. Enjoy using the links to help you make your own Trompes. I have more self explanatory pics available free upon request.
://www.paenvironmentdigest.com/newsletter/default.asp?NewsletterArticleID=26855
https://wallaby.telicon.com/pa/library/2013/20131021tm.pdf
Here’s a You Tube link to the same:
https://youtu.be/I85esMMoRa4
Hello, I have a pond 100x100x 7 ft, with some baby fish growing. The pond has not been care for in the past 6 yrs. I am looking for natural way to bring it back to nature in a economic way..
we currently live in Zone 3-5 ( Toronto county side) and have plenty of frogs, slugs, lichees, overgrown algee and a lot of dead maple leafs.
Can you guide us to create a permaculture solution to make Our pond cleaner and sustainable and possibly swimmable.
Hi i’m looking for the video link called: How to create a permaculture design…it featured Geoff with a guy name Dan or
Daniel Halsey which I tought was extremely interesting. Can you please provide a link thks!