Joseph Morton Caldwell, 69, who retired in 1973 as chief of the engineering division in the Directorate of Civil Works in the Office of the Army Chief of Engineers, died of complications from influenza Sunday at Arlington Hospital.

He had been head of the engineering division of the directorate since 1971. The directorate handles the planning, engineering, design and construction and operation of all civil works projects of the Army Corps of Engineers.

With his retirement, Mr. Caldwell ended 40 years of service with the Corps of Engineers, all of it in a civilian capacity except for four years during World War II, when he was on active duty as an engineering intelligence officer. He had in Arlington since 1943.

Mr. Caldwell was born in Yazoo City, Miss. He was a graduate of Mississippi State College.

He joined the Army Corps of Engineers at the Waterways Experiment Station in Vicksburg, Miss., in 1933 and was in charge of all hydraulic model testing there until he went on active military service in 1942. He was on the staff of the Army Chief of Engineers during the war.

In 1946, Mr. Caldwell joined the research division of the Beach Erosion Board here. He served as chief of the division from 1951 until 1963, when the board was converted to the Coastal Engineering Research Center. He was technical director of the center for seven years.

He twice was awarded the Army Department's Meritorious Civilian Service Award, in 1962 for work in the design of emergency hurricane protection and in 1973 for supervision of engineering and design of the civil works program of the Corps of Engineers. He also received the Southeast Asia Civilian Service Award of the Navy for his on-site support of port development in Vietnam in 1965.

Mr. Caldwell had served as U.S. chairman of the U.S.-Canadian Columbia River Treaty and was a delegate to several World Energy Conferences. He was the author of articles for an number of technical publications.

Since retiring from federal service, he had been a consulting engineer to private industry and government. He had spent an extended period in India for the United Nations.

He was a member of the National Academy of Engineering, the Washington Academy of Sciences, the American Society of Civil Engineers, the American Geophysical Union, the International Association for Hyddraulic Research, the Marine Technology Society and the Cosmos Club.

He had been active in the Boy Scouts and taught Sunday School for 35 years at the Second Church of Christ Scientist, in Arlington.

Survivors include his wife, Moselle S. of Arlington; a son, Jeffrey M. of Berkeley; Calif.; a daughter, Courtney C. Knowles of Arlington, and a brother, Dr. John T. of Raleigh, N.C.