Irrigation Canals of the Sacred Valley
The Sacred Valley of the Urubamba, sometimes called the “Sacred Valley of the Incas,” was the agricultural heartland of the Inca state and contained some of the most important irrigation works in the pre-Columbian Americas. The valley is a stretch of the upper Urubamba River valley northwest of Cusco, between the towns of Pisac and Ollantaytambo, at an elevation of approximately 2,800 to 3,500 meters, and it includes a network of irrigation canals that brought water from the upper slopes and the river itself to the agricultural terraces on the valley floor and on the surrounding hillsides. The canals are still in use in many parts of the valley, although they have been modified and extended by Spanish and modern interventions, and they are an important part of the Sacred Valley’s surviving infrastructure of the imperial Inca period.
The setting and the hydrography
The Sacred Valley is a region of mild climate, fertile soil, and abundant water. The Urubamba River, which runs through the valley, is fed by a series of tributaries that descend from the surrounding peaks, and the valley itself receives relatively little rainfall, with most of the precipitation falling on the slopes of the mountains. The combination of fertile soil, abundant water from the tributaries, and a relatively dry climate made the valley an ideal location for intensive agriculture, and the Inca developed an elaborate system of irrigation to take advantage of these conditions.
The principal tributaries of the Urubamba in the Sacred Valley include the Patakancha, the Huarocondo, the Ccorimarca, and the Cusichaca, each of which descends from the surrounding mountains and joins the Urubamba at a different point. The tributaries are fed by springs and snowmelt, and the flow is relatively reliable throughout the year, with the highest flow in the wet season between November and April and the lowest flow in the dry season between May and October. The Inca used the tributaries as the principal sources of irrigation water, and the canals of the valley typically begin at a spring or at a point on a tributary where the water can be diverted into a canal.
The Pampamarca canal
The Pampamarca canal is one of the most important irrigation canals in the Sacred Valley. The canal begins at a spring on the slopes of the Pampamarca mountain, on the north side of the valley, and runs for approximately 12 kilometers along the contour of the hillside to the agricultural terraces of the lower Sacred Valley. The canal is built of polygonal stones, with a fine lining of clay or sandy soil that reduces seepage, and it is cut into the bedrock in many places. The canal is still in use, although it has been modified and extended by Spanish and modern interventions.
The Pampamarca canal was a major engineering undertaking. The construction required the excavation of a channel through solid rock in many places, the building of retaining walls in loose or unstable ground, and the installation of a sequence of small drops and channels that maintain a steady flow despite the irregular topography. The canal was administered by the camayoc, the master craftsmen, who were responsible for the maintenance of the canal, the distribution of the water, and the ritual offerings at the principal sources.
The Chinchero canal
The Chinchero canal is another major irrigation canal in the Sacred Valley, supplying the agricultural terraces on the plateau above the town of Chinchero. The canal begins at a series of springs on the slopes of the Chinchero mountain, on the north side of the valley, and runs for approximately 8 kilometers to the agricultural terraces. The canal is built in the standard imperial form, with a polygonal retaining wall, a fine lining of clay or sandy soil, and a sequence of small drops and channels.
The Chinchero canal is integrated with the agricultural terraces of the plateau, which are among the most extensive in the region. The terraces produce maize, potatoes, quinoa, and a range of other crops, and the agricultural production of the plateau supported the population of the town and the imperial administration. The canal is still in use, and the water continues to flow through the channels in much the same way as it did in the imperial period. The canal has been the subject of archaeological and ethnographic study, including work by the Cusichaca Project in the 1970s and 1980s, which has demonstrated the technical sophistication of the system and its continuing importance for the modern agricultural economy of the region.
The Pisac canal
The Pisac canal is a major irrigation canal that supplies the agricultural terraces of the site of Pisac. The canal begins at a spring on the slopes of the Pisac mountain, on the south side of the valley, and runs for approximately 6 kilometers to the agricultural terraces. The canal is built of polygonal stones, with a fine lining of clay or sandy soil, and it is cut into the bedrock in many places. The canal is still in use, and the water continues to flow through the channels and to irrigate the terraces in much the same way as it did in the imperial period.
The Pisac canal is integrated with the agricultural terraces of the site, which include more than 30 levels of terraces built on a steep mountainside above the town of Pisac. The terraces are among the most extensive in the region and produce a wide range of crops. The system is one of the most complete in the Sacred Valley, and it has been the subject of detailed study by Peruvian and international researchers.
Other canals of the Sacred Valley
In addition to the Pampamarca, Chinchero, and Pisac canals, the Sacred Valley includes a network of smaller canals that bring water from the tributaries of the Urubamba to the agricultural terraces on the valley floor and on the surrounding hillsides. The canals of Ollantaytambo, the Yucay canal, the Urubamba canal, and the canals of the Maras and Moray region are all part of this network, and they demonstrate the technical sophistication of the Inca irrigation system.
The Ollantaytambo canals, in particular, are among the most extensive and best-preserved in the region. The canals bring water from the Patakancha River to the agricultural terraces on the valley floor, and they are integrated with a system of fountains and channels that supply water to the lower town. The canals are still in use, and the water continues to flow through the channels in much the same way as it did in the imperial period.
The canals of the Maras and Moray region are also notable. The Maras canal brings water from a salt spring on the slopes above the town of Maras to the famous salt evaporation ponds of Maras, which have been in continuous use since the imperial period. The Moray canal brings water from a natural spring to the agricultural terraces of the Moray site, and the canal is still in use.