LOCAL APPLICATION OF THE TECHNIQUE WATER HARVESTING IN POOLS AND CISTERNS 34

LOCAL APPLICATION OF THE TECHNIQUE

Technique:	WATER HARVESTING IN POOLS AND CISTERNS
Local name:	Qochas and Waru Waru
Site:	Lake Titicaca, BOLIVIA

Location

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Continent: South America
Country: Bolivia
Site: Lake Titicaca
Coordinates:
Lat: -15.75
Long: -68.64

Description of the local variant of the technique

Agriculture on the Bolivian plateaus is a high risk occupation. This region lies atan elevation of 4.000 m above sea level and around Lake Titicaca presents a strong climatic variability and a high degree of solar radiation, and also long periods of draught as well as persistent rains accompanied by floods. Before the Lupacas and Tihuanaco Inca period, a vast irrigation system was created, both for agriculture and for climatic control, around the lake, applying a very effective technology (the qochas and waru waru). The “qochas” are artificial depressions, something like wide wells, filled by rainwater which is used for agricultural irrigation purposes. They usually have an elliptical shape, sometime rectangular, sometimes irregular. Their depth varies but it is never less than 2 m, the width anything between 90 and 150 m in diameter, thus covering an area of 6000 to 13000 m2. The qochas may collect and retain water for several months, reducing the risk of damage to crops by frost, and also providing water for domestic use and for the animals. Nowadays many qochas are deteriorating due to human activity and salinization. The “waru waru”, also known as “camellones”, are a combination of long narrow, high and low strips of land, about 2 m wide and very long. The lowerstrips are submerged by 1 m of water whereas the higher are cultivated. On lake Titicaca, for example, the height of these fields ranges between 20 and 75 cm, the width varies from 5 to 10 metres and their length may reach 50 m. The advantage of such system of cultivation in these regions is apparent: irrigation and drainage of arable land are made easier, but most of all it regulates the microclimate of high ground cultivations. This is very important since a rise by one metre in the water level of the lake would flood 25.000 hectares of arable land. With this system over 10 tonnes of potatoes per hectare can be produced, as opposed to 4 tonnes in areas away from the lake. Recent experiences have shown how the waru waru technique requires a minimal capital investment, how effectively it exploits collective work practices and how it encourages production and productivity in indigenous agriculture.