The people of the Andean highland civilizations were expert hydraulic engineers. Ideas gleaned from archaeological work on their constructions have recently enabled many modern communities to increase their agricultural productivity.
The people of Tiwanaku constructed an elaborate and extensive system of raised fields on the shores of Lake Titicaca at Pampa Koani. Here some 8000 hectares of swampy ground were made cultivable by canalizing the River Catari which flowed through the centre of the area and by constructing drainage channels between which raised plots were made by mounding up earth.
Experimentally it has been shown that not only do these raised fields greatly increase fertility but also the association with water helps maintain a raised temperature at night, preventing the frost damage to crops that is a major hazard to the region's agriculture. In addition the canals supported fish and wildfowl, important sources of protein.
The Huari, contemporary with the Tiwanaku people, built long irrigation canals bearing water from high altitude springs and streams to terraced fields they constructed on the sides of the steep Andean slopes, in which they grew maize.
The Huari may also have been responsible for introducing the expertise that enabled the lowland Nazca people to build underground aqueducts.
