Hydrogeology and Paleohydrology of Ancient Machu Picchu

• Published in: Groundwater
• Main Authors: Wright, Kenneth R., Witt, Gary D., Zegarra, Alfredo Valencia
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: Computers in Earth Sciences; Water Science and Technology; Inca; Ice cap
• Online Access: http://dx.doi.org/10.1111/j.1745-6584.1997.tb00131.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1745-6584.1997.tb00131.x; http://onlinelibrary.wiley.com/wol1/doi/10.1111/j.1745-6584.1997.tb00131.x/fullpdf

Abstract The study of the ancient Inca water supply of Machu Picchu was performed by the authors under an archaeological permit issued by the Peruvian Government in 1994. The study included an evaluation of the hydrogeology of the ancient spring water supply situated on the north slope of the mountain of Machu Picchu and its relationship to the Machu Picchu fault. Based on field measurements, the yield of the primary spring has a seasonal variation of between 25 and 125 liters per minute. This flow adequately provided the domestic water requirements of up to 1000 inhabitants of the mountain top royal retreat of the Inca ruler Pachacuti, occupied primarily between 1450 and 1540 AD. The permanent population between visits of the Inca ruler was about 300. Final abandonment occurred in 1572 AD. The estimated geologic catchment area related to the Machu Picchu fault is roughly 50 percent greater than the topographic basin area. A 749 meter‐long canal delivered the spring flow to the center of the community to serve a total of 16 water supply fountains. A theory that a water shortage caused Machu Picchu to be abandoned proved to be unsubstantiated based on a study of the Quelccaya Ice Cap corings data that demonstrated that the last decade of the occupation was wetter than the previous eight decades. The builders of Machu Picchu developed a community domestic water supply using the spring and a hydraulic infrastructure in an effective and efficient manner. They utilized a gravity flow canal sized to carry the spring flow with a suitable safety factor against overtopping.