Samples of the Story
Preface
Author’s Note
1. The Elixir of Life
2. Farmers and Furrows
3. “Whoever has a channel has a wife”
4. Hohokam: “Something that is all gone”
5. The Power of the Waters
6. Landscapes of Enlil
7. The Lands of Enki
8. “I caused a canal to be cut”
9. The Waters of Zeus
10. Aquae Romae
11. Waters that Purify
12. China’s Sorrow
13. The Water Lily Lords
14. The Triumph of Gravity
15. The Waters if Islam
16. “Lifting Power more than that of a Hundred Men”
17. Epilogue
Notes
Acknowledgements
Index
| Book Extracts and Table of Contents
Chapter 14: The Triumph of Gravity
1400 C.E. Tipon, near Cuzco. Spring. A small group of water engineers cluster around a flat boulder in the morning sunshine. Two of them bear quipus, the ubiquitous knotted strings used by Inca scribes as inventories. They are calculating potential maize yields from the ravine below them. Meanwhile, a finely dressed engineer watches his assistants as they puddle fine clay and deftly create a model of the valley and surrounding hillsides. Carefully, they mark the position of the hillside spring above the ravine and the course of the nearby Rio Pukara. The engineer tells them to make another model, this time with the valley filled in from the hillside to the east. He marks off a series of terraces on the fill, plots in canals, develops a mental plan of the great estate within the already existing stone enclosure wall. This anonymous engineer and his peers created a hydrological masterpiece, a triumphant use of gravity.
Tipon lies 13 miles (21 kilometers) downstream from Cuzco, a 500-acre (202-hectare) self-contained and walled estate that may have belonged to the ruler Viracocha Inca in 1400. The estate is in a ravine, at its head the perennial Tipon Spring. It results from the same kind of geology that provided water for ancient Greek cities—a solid volcanic layer overlying permeable limestone strata.
Viracocha’s engineers began by filling in the valley. They piled boulders and rock fill, then smaller cobbles, gravel, and sand to form a huge natural filter. Then they built 13 terraces that extend 1,300 feet (396 meters) up the ravine, filling them with rich topsoil in which the estate grew maize, flowers, and herbs--prestige crops. The massive stone walls of the terraces resisted soil pressures and earthquakes, the irrigation water and rainfall percolating effortlessly through the natural reverse filter without adding hydraulic pressure to the walls. Near-vertical defiles, water drops, built into the terraces controlled the water flow of the spring upslope.
The terraces, carefully integrated one with the other, act like a stairway down the filled-in ravine. The noble residences, a two-story grain store, and a military facility overlook them. A long irrigation canal from another valley surrounds the terraces on three sides. Six hundred feet (182 meters) northwest lies a large ceremonial plaza, an aqueduct, and a religious complex. The nobles and their retinues of estate managers and craftspeople dwelt in a small community of about 100 people, immediately to the north. Every arable part of Tipon was terraced for cultivation, for either irrigation or dry agriculture. A massive defensive stone wall surrounds what was a substantial community, rising to a height of 15 to 20 feet (4.6 to 6 meters).
Flood irrigation allowed the estate farmers to grow two maize crops a year, one harvested in January, the other in July. By using three canals, the water managers could distribute water to the entire terrace system, also to the palace and ceremonial plaza area and the dwellings nearby. The Tipon spring produced about 300 gallons (1.356 cubic meters) of water a minute. The builders faced the spring with a stone wall and three spouts that enabled a user to draw water into a pot. Downslope, the stone-lined discharge channel bifurcates and bifurcates again, enabling the managers to direct water in different directions. The carefully engineered canals and their drop structures ensured an even flow.
The uppermost two central terraces lie above the Tipon Spring. They received water from a side channel from the main canal that brought water from the perennial Rio Pukara. Three irrigation canals carried water from the river, about 0.84 mile (1.36 kilometers) north of the central terraces. The main channel followed the contours and provided water to surrounding agricultural tracts, at times dropping sharply down steep slopes, with an average gradient of about 10%. Next to the ceremonial plaza lies a 200-foot (61-meter) long boulder aqueduct standing 15 feet (4.5 meters) above the ground, with a pedestrian underpass that also released flood water.
Most irrigation systems are utilitarian at best, but to the Inca, such works were also symbols of human control over water. Tipon was an enclave of privilege, where the ruler and his nobles could live in comfort to the sound of soothing water that flowed day and night and never ran short. At the same time, the engineers built for the long term, blending their canals and water drops effortlessly into the natural environment in an ultimate display of the power and use of natural gravity.
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