Harold Christy received his M.S., Civil Engineering in 1925 and C.E. Professional degree in 1946, both from the University of Arizona. Schwalen joined the faculty of the Agricultural Engineering Department in 1919, after two years' service with the 340th Field Artillery in France during World War I. He terminated active service with the University in 1965, having achieved the longest record of full-time service of any person who has ever retired from the University of Arizona. Schwalen served in many positions including assistant irrigation engineer and professor and head of the Agricultural Engineering Department. His name was virtually synonymous with the University in matters relating to agricultural engineering. His research dealt with the location, drilling, and testing of irrigation wells, the design and operation of pumping plants, and the conveyance of irrigation water from the point of supply to crop land. During World War II, Schwalen was the senior irrigation engineer for the Guayule Emergency Rubber Project U. S. D. A., 1942-1943. Schwalen held memberships in Kappa Sigma fraternity, the Masonic Lodge, Tucson Rotary Club, and the Old Pueblo Club. He additionally belonged to numerous professional and learned societies.
The collection mainly contains data from Schwalen's various research projects after 1919.
The remainder of the Schwalen papers contain research notes and calculations, maps, photographs, correspondence, and reports that cover the Department of Soils, Water and Engineering consulting projects; work at the University's experiment stations; and surface and groundwater studies in Arizona. Additionally, there is a collection of manuscript reports by Schwalen and others, legal documents and miscellaneous studies on water-related topics.
Two linear feet of photographs, dating from 1919-1966, depict subjects including: floods and erosion, well drilling, pumping equipment, weirs, sprinkler irrigation, adobe construction and others. Original order has been retained due to the difficulty of identifying many of the photos. These are organized by subject or place, and in some cases, by township and range. Approximately 2000 unidentified negatives have been filed under topics or places where possible. The Library would appreciate researchers' help in making further identification.
Recorder strips for Cortaro Farms span the years 1918 to 1964.