Lessons from Latrines
If you grew up in a rural area, you may have become used to septic systems for sewage processing. In a septic system, a large tank enables a microbial mix to interact with wastes and break them down. Then a series of porous pipes allows the processed wastewater to percolate through soil. By the time it's done, the E. coli are a very minor component of the microbes in the water.
But that's not possible in the rainforest. The soil simply doesn't percolate. Imagine an impermeable layer of plastic, just a few centimeters below the surface of the soil. So, to keep wastes out of the precious river water, deep pits must be created for waste processing.
There are many more implications of the clay soil in the area of Iquitos. It's almost impossible to build roads--no concrete, no rocks. Buildings over two stories fall down. And since the river rises as much as 16 m (50 feet) in the summer, bridges are almost impossible to maintain.
Was the soil always so poor? Some experts (such as Charles C. Mann in his book 1491) assert that the native peoples of Meso-America were experts at soil engineering. By mixing charcoal and fish compost, they were able to create soils that retained nutrients and water for long periods of time, and had great success raising high levels of food crops.
Not a problem. The ingenuity of the people and the ease of travel on their real highways--the rivers--makes travel possible.
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