Professor Peter S. Eagleson began working at MIT in 1952 and served as the head of the Department of Civil and Environmental Engineering from 1970 to 1975.  He was a pioneer in the field of hydrology, transforming it from an engineering specialty with local application into the global-scale study of the water cycle. His 1970 book, Dynamic Hydrology, provided radically new perspective on the movement and storage of water in the environment. The water cycle's interface with the climate system and biogeochemical cycles and its interactions with the biosphere were hallmarks of his new vision. In a series of seven papers under the main title Climate, Soil, and Vegetation -- published in a single issue of Water Resources Research, the main journal of the discipline – he demonstrated the potential of this new thinking for addressing some long-standing disciplinary and interdisciplinary challenges.

In 1991, the National Research Council published Opportunities in the Hydrologic Sciences, the report of a committee chaired by Professor Eagleson. This report recommended a new vision for the field of study that built on his pioneering ideas.

Following his retirement from MIT, Professor Eagleson continued producing inspiring new ideas. He published two books: Ecohydrology (2002) and Range and Richness of Vascular Land Plants (2009); these works ushered in yet another transformation of the discipline by bridging the fields of hydrology and ecology.

He served as the president of the American Geophysical Union from 1986 to 1988. In 1992, he was MIT Killian Award lecturer, the Institute’s highest faculty honor.