In 1903 the United States Department of Interior, through the Bureau of Reclamation (then called the U.S. Reclamation Service), recommended that a dam be constructed across the Colorado River between California and Arizona above Yuma. It would be the main feature of an irrigation system meant to divert water to the arid land below the dam on either side of the river.


While in India, U.S. government representatives also picked up the story of the ancient Hindu God Indra, who at one time, represented thunder, lighting and rain. Indra (who had four arms and was represented by the swastika with its four arms) had the power to control water. There were those in the U.S. government who thought the swastika would be a fitting symbol for the U.S. Reclamation Service. During its early years the United States Bureau of Reclamation used the swastika for its symbol. The swastikas on Laguna Dam are a legacy of that period.


The Service also designed a Reclamation flag with a large swastika at its center with the U S R S letters in the four corners. It is not known how long the swastika was used by the Service, if any other structures ever exhibited the symbol or when the Reclamation Service dropped the Symbol. When impassioned citizens, however, wanted to destroy the swastikas on Laguna Dam during W.W.II, guards were posted around the clock to protect the site. Laguna Dam is the only government project left standing in the United States where swastikas are an integrated part of the structure.


Courtesy of Walter S Frank (smoter.com)

Links to the whole story and more information:
The Swastika Dam - Swastikas on the Colorado
Laguna Dam Information