(Image of Machu Picchu courtesy of Martin St-Amant - Wikipedia.)
Airing tonight (February 2, 2010) at 8pm on PBS stations: NOVA's Ghosts of Machu Picchu. Set your DVRs now! If you miss the program, it will be streaming online starting February 3.
Machu Picchu is an Inca engineering marvel: located 8,000 feet above sea level, it contains 200 stone structures placed on a complex set of roughly 700 terraces. What's most surprising is not its buildings, though -- it's all about what was built underneath the structures. Underground, complex engineering has allowed the site to withstand 76 inches of rainfall per year (that's 2.5 times what Chicago gets) for over 500 years. Machu Picchu is all about water: it is constructed to last, using complex engineering to manage and divert water. Within the complex, more than 100 drains divert rainfall down the mountain; a system of 16 fountains (flowing at between 6-30 gallons per minute depending on the time of year) provided drinking water for a population of up to 1,000 people; and complex soil engineering allowed the terraces to withstand the pressures of rain and earthquakes. So how did the Inca -- lacking steel tools and the wheel -- make this place? How could people live in such a remote place, and how did they grow so much corn -- a "royal food" of the time? This week's NOVA explains.
Included after the video is an interview with Ken Wright, a hydrologist who appears in the documentary. Click on through to check it out!
Interview With Ken Wright, Hydrologist
Ghosts of Machu Picchu features the work of Ken Wright, a hydrologist who has worked on the site for 15 years, in cooperation with National Geographic. Wright and his wife Ruth wrote several books on Machu Picchu including, Machu Picchu: A Civil Engineering Marvel and The Machu Picchu Guidebook: A Self-Guided Tour. Together, the Wrights have garned incredible accolades for their work (check out this image showing their collection of awards, including honorary professorships). I was able to ask Mr. Wright a few questions after previewing tonight's NOVA episode -- read on for his answers!
mental_floss: As a modern hydrologist, were you surprised to discover the hydraulic engineering sophistication of the Inca?
Ken Wright: Both my field research colleagues and I were surprised to discover the level of hydraulic engineering performed by the Inca. Â Field evidence leaves no doubt about what they knew and how they accomplished their engineering feats.
m_f: Do you have a sense of what tools were available to the Inca -- how might they have determined a level surface, or measured a precise grade over distance?
KW: Yes, we do know what tools they had. Â The Inca had a variety of hammerstones, bronze levers, bronze knives, plumb bobs, rope and string. Â They used clay models for conceptualization and for determining a precise grade, they had nice pottery and stone basins, about 18 inches in diameter, that they filled with water to use as levels.
m_f: What first drew you to study Machu Picchu?
KW: I was first drawn to Machu Picchu by the then-unanswered question: where did the Inca get their water for Machu Picchu?
m_f: This is a slightly silly question, but it nagged me a bit while watching the documentary. Â The terraces appear to be covered by grass today (though perhaps in the past they were planted with corn). Â The grass looked very tidy. Â Do you know if someone mows the grass?
KW: The trimmed grasses on the terraces of Machu Picchu are maintained by free-range llamas and alpacas. Â For the steep terraces like Huayna Picchu, where the animals can't get, the Peruvian government hires macheteros (laborers with machetes) to keep the grasses under control.
For more from Ken Wright check out this excellent interview on the NOVA website.
Images From The Documentary
Images courtesy of Ricardo Preve, showing some scenes from Ghosts of Machu Picchu.
Thanks to WGBH for providing an advance copy of the episode, the images above, and access to Ken Wright. I was not paid or otherwise compensated to review this episode of NOVA -- I wrote about it because it's awesome, and you should watch it!