Luna B. Leopold, a gifted scientist and influential conservationist who turned the study of rivers and how they shape the landscape into a science, died February 23 at his Berkeley, Calif., home. He was 90.

Leopold was the son of eminent wildlife ecologist Aldo Leopold and edited “A Sand County Almanac,” his father’s classic 1949 book that through its poetic explanations of the workings of the natural world became a cornerstone of the environmental movement.

The younger Leopold embraced his father’s belief in the importance of “harmony between men and land” and inherited his skill at observing the environment. He studied America’s natural waterways and became a seminal figure in his own right. His research demonstrated fundamental principles about the dynamics of rivers and streams and their role in the ecosystem.

“How does water move and when it moves, what happens? How does land shape water flow and how does water flow shape land? These are among the central issues that Luna solved,” said Char Miller, an environmental historian at Trinity University in San Antonio.

He sat on the boards of the Sierra Club and the Environmental Law Institute, and was an early and vocal critic of clear-cutting, mining in national parks, and the unrestrained use of water for irrigation.

Leopold was chief hydrologist at the U.S. Geological Survey for two decades, and was credited with transforming its water resources division into one of the nation’s leading agencies for water research. The author of close to 200 scholarly papers, he later taught earth and planetary science and landscape architecture at the University of California, Berkeley.

He was known as an intrepid outdoorsman and field researcher who floated down many of America’s rivers on a raft and piloted a plane over Alaska. He was famous for his camp cooking on a Dutch oven – strawberry shortcake and standing rib roast were specialties.

Leopold was born in Albuquerque, N.M., on October 8, 1915. His father was a forester, educator and philosopher who served in the U.S. Forest Service for 19 years. After studying geology and meteorology at UCLA, he served as chief meteorologist for the Hawaiian Pineapple Institute, where he developed a long-range weather forecasting system for pineapple and sugar cane plantations. He received a doctorate in in geology from Harvard University in 1950 and joined the Geological Survey as a hydraulic engineer.

A member of the National Academy of Sciences, he was awarded the National Medal of Science in 1991.