Dr. Omar Turney (November 1, 1866 – December 21, 1929) was an American archaeologist and engineer. He had been employed beginning in 1888 as an assistant engineer on the rebuilding of the Arizona Canal Dam. And was later employed as a surveyor for the Santa Fe, Prescott and Phoenix railway. He also served successively in the United States geological survey and in the United States reclamation service. He was one of the principal sponsors of the Roosevelt Dam, and is largely responsible for the name given to the Dam. For 12 years after leaving the government service Dr. Turney served the cities of Phoenix, Mesa, Tempe and Glendale as city engineer.

In his last year of life Dr. Turney published a series of articles in the Arizona Historical Review entitled “Prehistoric Irrigation“, the result of the collection of data over a period of more than 40 years.

In 1929, Dr. Omar Turney, created a map of the Salt River Valley showing the results of exhaustive surveys cataloging Hohokam Canal systems in the Salt River Valley. Dr. Turney’s astonishment and respect for the accomplishments of these ancient Hohokam engineers is evident in the text of the map “these were the original engineers, the true pioneers who built, used and abandoned the canal system when London and Paris were cluster of wild huts”.

Turney’s survey is the most definitive of the Salt River Canal system ever created. It was the product of observations made over the course of more than 40 years of study, and the map shows dozens of prehistoric canals on both sides of the Salt River in the vicinity of Phoenix, Tempe and Scottsdale. The map accompanied Turney’s multi-installment prehistoric irrigation in the 1929 Arizona Historical Review.

Turney’s map provides a record of the Hohokam Canal System which would be unmatched until extensive aerial surveys became available, and goes beyond this to supply irreplaceable archaeological evidence for the ruins of abandoned prehistoric temples and settlements in the area, subject to destruction at the hands of European settlers.

Turney laments: “40 years ago few [Hohokam Canals] had been destroyed. One by one we have seen them torn down, but so many remained that it seemed the whole story of the early race could be told many times over from those that remained. With keen resentment we heard an outsider come here and declare that all were gone. When this report was begun, it still seemed that plenty remained, we drove about to measure them up and with astonishment found that 31 edifices of the past are now of the past themselves: only two remain. As a report, this preliminary has become an obituary!”

Also, many of the Hohokam ruins found in the Salt River Valley are recorded with precision only on this map. In addition to specific temples in pueblos, the map notes the location of pictographs, pictoglyphs, and hieroglyphs throughout the region. A ceremonial grotto is marked on the Camelback Mountain, as does Phoenix’s famous “Hole in the Rock” landmark.

Confusingly, several of the names of ruins found on the map are drawn from Mormon scripture. Turney noted in his third installment of prehistoric irrigation that: “Casa de Nephi was so named in thanks to the leaders in the Mormon church for their long and untiring efforts to check and verify every detail of the Turney map in their part of the [east] valley. Names in this locality are taken from the book of Mormon.” Other such place names include Pueblo Moroni and Pueblo Lehi.

The personalizing feature appearing on the map is on the north bank of the Salt River is the “Park of Four Waters“. Turney chose this location – now part of the Pueblo Grande Museum – to be the final resting place of his ashes after his death.