iAVs had its roots in a quest to develop a new method of agriculture for arid-zone underdeveloped regions such as the African Sahel.
While the following images depict the development of such a low-cost, low-tech iAVs, a similar system can meet the needs of a family of four for fresh fish and nutritious vegetables……in a space no larger than a parking spot at your local supermarket.
In its simplest form, an iAVs comprises a grow bed containing medium-coarse sand (which functions as the bio-filter and plant substrate) which drains into a fish tank.
The grow bed and fish tank can be made watertight with puddled clay, plastic liner or fibreglass.
Furrows are formed in the sand and seedlings are planted into the high sections of the furrows.
Nutrient-rich water is intermittently transferred from the fish tank into the furrows.
As the water percolates down through the sand, the fish solids are trapped and mineralised and become nutrients for the plants. The clean water drains back to the fish tank.
This symbiotic partnership will see the water recycled up to 300 times before it is used up by the plants.
eir could be woven stick and thatch, or brick/rock wall, scrap tin, logs & mud, boards……whatever is available. Many alternative configurations…..both low/hi tech are possible.
Return (drainage) with cascade aeration is not clearly depicted.
The iAVs provides for 100-fold greater water use efficiency over traditional pond culture of tilapia with (the nutritionally and economically dominant) vegetable production for the same amount of water that it would take just to grow the fish.
Total annual water consumption is as low as 5 cubic metres/year for each cubic metre of fish culture volume – with a significant fraction of that water use in the form of edible biomass.
Credits: Pastel renderings (art) by Brandy Noon, a Kenyan, circa 1992. Captions by Mark R. McMurtry.