Arthur A. Maass, a longtime Harvard government professor known for his work on the nation’s water policy, died March 26. He was 86.

Maass, the Thomson professor of government emeritus, served on the Harvard faculty for 36 years, from 1948 to 1984, before retiring and taking an emeritus position.

“He was the ideal academic on practical life of politics, “ said Samuel Beer, the Eaton professor of the science of government emeritus. “He had the right balance and right mind.”

Maass’ first book, Muddy Waters: The Army Engineers and the Nation’s Rivers, was published in 1951 and criticized the Army Corp of Engineers for shortcomings in its management of water resources, flood control and navigation procedures and for its relationship with special interests.

“His dissertation [Muddy Waters] was a fierce attack on the Army Corps of Engineers,” said Beer, who cited the work as one of Maass’ principle achievements.

Maass was also an innovator. Following the publication of Muddy Waters, he served for 10 years as Director of the Harvard Water Program, which created quantitative methods for designing and planning water resource systems.

In 2001, the Army Corps of Engineers dedicated a library reference room to Maass, recognizing his work in water management and particularly his influence on the Corps through Muddy Waters.

Maass served as chair of the government department from 1963 to 1967, and Beer hailed him as an exemplary leader and mediator within the department.

“He was the best department chairperson,” he said. “He could handle all the personal and ideological issues.”

Maass also wrote Area and Power, a book on federalism and local government, in 1959. His final book, Congress and the Common Good, was a 1983 analysis of how the public interest is incorporated into the procedures of Congress.

“He was highly intelligent, brilliant, and very independent,” said Aaron Maass, a grandnephew of Maass.

He added that Maass spent his leisure time and much of his retirement enjoying the Boston Symphony and immersing himself in reading about politics.

Aaron Maass said that his great-uncle was tenacious in sticking to his views during discussions.

“If he felt a certain way, you could not convince him any other way,” he said.

Maass, a resident of Boston’s North End, was well known in the neighborhood. Aaron Maass said that when he walked through streets or went to restaurants in the North End with his great-uncle, people would greet him as “il professore.”

Born in Baltimore, Maryland, Maass received a bachelor’s degree with honors from Johns Hopkins University in 1939 and a masters in public administration degree at Harvard in 1941, before graduating with a Ph.D. in political science from Harvard in 1949.

Maass served in the Navy from 1942 to 1946, and both before and after World War II with the Office of the Secretary of the Navy, the National Resources Planning Board and the U.S. Bureau of the Budget.