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No. 116: Mar-Apr 1998

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An Anasazi Reservoir

In Morefield Canyon, Mesa Verde National Park, Colorado, a strange earthen mound, 200 feet wide, rises 15 feet above the canyon's grassy floor. Archeologists have debated the mound's purpose for decades. Being elevated above the floor of a usually dry canyon as it is, the mound certainly does not seem to be a reservoir, but that is what recent research says it is.

The mound is shaped like an inverted frying pan, with a 1500-foot-long handle that leads to a normally dry stream bed higher up in the canyon. The Anasazi were excellent water managers and took advantage of the flash floods that roared down the canyon every few years. To impound some of this valuable water, they initially built a conventional reservoir, but it was soon silted up by the freshets. So, they gradually raised the reservoir walls and constructed a raised canal to the stream bed. It was all very logical.

The engineering of the canal is particularly impressive. The channel is 4-8 feet wide, but only 1-2 feet deep. Its steep, 15-foot-high sides are shored up with neatly aligned stones that were carried in from somewhere outside the canyon.

(Anonymous; "Mystery Mound Appears to Be an Ancient Reservoir," San Francisco Chronicle, June 6, 1997. Cr. D. Phelps. Also: Anonymous; "Mysterious Mesa Verde Mound Turns Out to Be a Reservoir," Deseret News, June 10-11, 1997. Cr. S. Jones.)

Comment. The closely related Hohokam Indians built miles of well-engineered canals where Phoenix now stands. See SF#19 for description.

From Science Frontiers #116, MAR-APR 1998. 1998-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987