Written by Doug Crouch
While it is a traditional agriculture that once produced heaps of food in central Mexico, Permaculturists often use the word Chinampa to mean something slightly different yet emulating this original highly productive form of aquaculture. The original system was essentially a form of aquaponics but of course with no pumps, no plastics, no holding tanks, and no electricity. Instead it was an edge enhancement growing system where quasi floating islands were created in the vast lakes of Mexico. While the surrounding locales were deficient in water supply, making agriculture difficult without pumps, pipes and electricity, the natives instead brought the agriculture to the water itself. To create the grow beds they staked out rectangular plots by driving posts downward in shallow areas and weaving these posts together with canes in a wattle. From there they extruded upward with layers of materials that included thatch material grasses like Typha and Juncus that grew
on the waters edge to land. They would layer that with the pond bottom muck or detritus as it is known scientifically. From there they could paddle around in boats and grow crops on these islands, which in time grew fertility. Vegetables knew no limit of water or fertility as it was easily gained from the soluble nutrients in the water with its access to the cycling of the compost pile like material of the lake bottom. Waters nutrients are creatively cycled inherently and were easily exploited due to edge creation and creative human interaction. These food growing systems allowed the natives to build complex cultures and some of the highest, if not the highest, population density at the time in the whole world. Although the Spanish did a number on the people population and the chinampa system itself as industrial agriculture developed, the chinampa system remains alive and continued on by a small group of locals and even some permaculturists are involved. In today’s modern world one is able to purchase something similar known as floating islands yet are made of synthetic materials. Although plastic, they are made in the thatch like pattern similar to what the indigenous of Lake Titicaca did for their floating islands. However this design comes from biomimicry with essentially the same materials and mold as an air filter in a machine. It has lots of edge to trap particulates when applied to machinery but when you make them bigger and put them in water the trapped particles of air create the buoyancy. These floating mats are covered in microorganisms which help to cleanse the water of pollutants and nutrients and give a planting space for wetlands plants and vegetables.
Modern Day Permaculture Application
When working in Costa Rica in 2005-06, I had the fortunate opportunity to see an amazing project in the islands of Bocas del Toro, Panama. After crossing the border, we quickly found ourselves on a boat weaving through incredible coastal habitat of mangroves and islands of aquatic vegetation acting as a buffer strip to the coast and creating lots habitat. It was easy to get inspiration from this natural habitat on our journey to the project Finca Luminescence on the island of Bastimentos. Upon arrival at the little coastal island, we were astonished at the amount of edge and biodiversity at the project. After a short walk through a coastal hamlet of indigenous people, you entered into the property and immediately controlled chaos was apparent. Water surrounded everywhere, layers of aquatic vegetation were abounding and the vegetation on land was also extremely layered and visibly still young. We heard bird calls, frog croaks, and even large creatures scurrying to enter the water. On a small ridge point you could overlook to the neighbors property and it was a classic low diversity, cattle pasture so famously implemented by the Spanish through draining of wetlands and sowing with invasive grasses.
Chinampas- Reconstructed Wetlands
What Bruce Hill, Argentinean Permaculturist and one of the first to take Bill Mollison’s course, and crew had done there was amazing and yet so simple. Digging and mounding, giving water back its habitat rather than ushering it outward to destroy coral reef through channeling and poor land management. Rather a paradise of biodiversity was created through edge and giving back the land what it once was. So this is how I have heard the word chinampa be used most in Permaculture circles- reconstructed wetlands. It’s easy to understand as Bill Mollison uses the word chinampa in drawings where peninsulas are created in a water body to give edge. Thus the interpretation by permaculturist comes in many forms but the basic pattern itself is there.
Whether big like this project in Panama or a small one I did in New Zealand, the way to do this is to move water through a site as slow as possible through a series of channels and ponds interfacing with land as much as possible; edge with the sinuous and dendritic patterns. Islands can be created so fowl can flourish or bamboo has a defined space. Furthermore, edge is created within the water bodies so that three dimensionally there are shelves for different aquatic vegetation to grow on and different creatures to carve their niche. Energy is further cycled through
aquatic vegetation being harvested and brought onto land as a green mulch to build soils quickly. This is especially important in the tropics as soil building happens quickly but the mulching process must be done diligently to ensure success and maintain the small layer of humus that this climate allows for. Pipes can be added like in the system in Panama as a way to further access (so paths and roads can go over) and also to accurately regulate water height. This allows for edge weed control in the beginning to eliminate the invasive grasses and to eventually be planted out with rice with the systems induced flooding potential. Furthermore, fish, ducks, and crayfish or prawn can all be creatively integrated and possibly harvested. In the context of Panama they choose to rebuild the ecosystem with five small native fishes, Malaysian Prawn, and the wild harvest of caiman. A small version of the alligator, these six foot (2m) reptiles were easily heard at night and seen at dusk and dawn. Skeeter, the alpha male, claimed ownership of the large pond below the boathouse.
These earthworks can either be hand dug or done with machinery depending on scale, time, and monetary investment. In Panama most of the initial project was done by hand employing 15 indigenous people mostly from the little hamlet in front of the property. First the Permaculture project got them fitted with running water and composting toilets to lift them out of poverty conditions in their hamlet. From there they were paid to dig the channels and ponds and lay the tiny bit of pipe that was needed. They used the two-man shovel technique that Bill Mollison outlines in his earthworks chapter. Unfortunately I have never used it or seen it so I can’t comment any farther on it. As the project wore on and a sickness inflicted one of the owners and jeopardized the project, Bruce turned to machinery to finish the job quickly.
In the chinampas implementation I helped to lead at a study abroad high school in Palmerston North, New Zealand, myself and the high school students did daily diggings, much of it done in their free time after school was let out. When digging, it can be free form or pegged out appropriately from the design. We did the former but over time the students got the pattern and began to just dig on their own with minor checkins with myself. The main thing to consider is access, which is why it goes from ponds to channels so access alleyways can be integrated. A water source must be present to initiate these projects. In the New Zealand case, the source was pooling from high groundwater in our garden beds creating poor growing conditions. Conventional wisdom would have been to dig a straight channel away from the standing water and move it out of the site immediately. Channeling is very commonplace in land management yet it could be different with the problem is the solution thinking. However with this mindset, we were able to create raised garden beds next to the water’s edge and grow azolla and duckweed to scoop out and fertilize the beds in relative location. These plants are great example of the principle use of biological resources as they carry so many nutrients and will compost around your veggies as a green mulch. Thus we lead the water away from the garden beds which were at the highest point in the fenced space and brought the water meandering downward in a slow and sinuous way. However, in Panama a stream was un-channelized and through creating so much edge the water slowly passed through the site. Along the way it was passively irrigating all of the land and allowing for an incredible regeneration speed to happen. From a barren cow pasture, degraded and in ruins, the land in an astonishing three years was a jungle of food with much more to come as well! The prawn harvest was definitely a treat as I had not had them from a wild harvest rather only from farmed ponds back in my aquaculture school days.
If flowing water is entering the land a silt trap should be added as to concentrate the maintenance of the silting action. It’s a large hole at the beginning of the series of earthworks where the water can initially wash itself of this load. Depending on the watershed above you, from time to time this will need to be dug out. Also to lessen the digging out process, aquatic vegetation should be harvested regularly to feed adjacent plantings and prevent too much of it dying and going to the pond bottom and becoming composted there. The detritus can build upwardly quite quickly and is a great resource to be scooped out but the free floating aquatic plants are much easier to harvest.
In the case of our chinampas in New Zealand, they only held water for half of the year when the rains were persistent and ground water high as this was a former wetlands area that had been, again, drained for pasturing cattle. In the bottoms of the channels you could sow a crop as these essentially were sunken beds. You could even squeeze in a grain crop depending on the dry season length. All in all these examples show the chinampa style thinking that many permaculturists employ to creatively interact with nature rather that seeing water as a negative energy; problems into solutions.
Written by Doug Crouch
Header Art by Sien Vierpost