CHICAGO (CBS) — City planner and Chicago River advocate Eric Yondorf is being remembered as an expert and a visionary, for his part in the decades-long effort to transform the river into one of the city’s crown jewels.

Mr. Yondorf, of the West Rogers Park neighborhood, passed away on Wednesday, July 18. He was 90 years old.

Born in Nuremberg, Germany, in 1922, Mr. Yondorf immigrated to the United States with his family in the 1930s. He initially studied electrical engineering at Northwestern University and worked for a few years as an electrical engineer with Westinghouse in Baltimore.

After serving in the Army Signal Corps during World War II, Mr. Yondorf returned to school under the GI Bill of Rights to study architecture and city planning at the Illinois Institute of Technology — launching what would become a nearly three-decade-long career with what was then known as the Chicago Department of Development and Planning. Mr. Yondorf’s term at the Planning Department lasted from in 1958 — during the early days of Mayor Richard J. Daley’s tenure — until 1986, toward the end of Mayor Harold Washington’s first term.

During his Planning Department tenure, Mr. Yondorf directed the publication of 10 development area reports that led to the transformation of several regions of Chicago in the 1960s. Mr. Yondorf also wrote a study urging the establishment of a tourism council for Chicago, and initiated a loft conversion study that led to the creation of the city’s first planned manufacturing district, along Clybourn Avenue on the edge of the Lincoln Park neighborhood.

And in 1982, Mr. Yondorf developed the Chicago Waterways Study, which included proposals for waterway protection and beautification that are now mandated by city ordinance. His dedication to the city’s waterways would last long after he retired from the City of Chicago.

Friends of the Chicago River executive director Margaret Frisbie remembers Mr. Yondorf for those efforts after his city career. He began as a volunteer with the group in 1986, and Frisbie described him as a mentor.

“He taught me everything,” Frisbie said. “He gave me my first lesson in how to think about river development and urban planning, and I know he did that for other people who worked here as well.”

As Friends of the Chicago River worked to transform the river from a neglected and smelly waterway to an accessible and beautiful corridor, Mr. Yondorf contributed a “broad planner’s perspective” that helped the group realize its efforts, Frisbie said.

“In these jobs, you need people that can see a way forward, and you need someone like Eric, who was energetic, and practical, and creative, and thoughtful,” Frisbie said.

Mr. Yondorf served on the planning committee with Friends of the Chicago River, which helped develop the Chicago River Corridor Development Plan.

The plan has gone on to change the face of riverfront architecture, Frisbie explained. Before the plan, buildings had regularly been built with their backs to the river, while contemporary construction such as the Trump Tower celebrates the river by facing it.

Mr. Yondorf was one of the longest-serving members of the planning committee, Frisbie said.

But Mr. Yondorf’s work with Friends of the Chicago River was hardly limited to the nonprofit’s offices. He served as a member and a captain of the river’s cleanup crews, guided tourists on river walks, and helped plant wetlands vegetation on the Prairie Wolf Slough in Deerfield, among numerous other feats in the field.

Mr. Yondorf was named volunteer of the year with Friends of the Chicago River in 1997, and received the President’s Award for Special Achievement and Urban Planning and Design from the nonprofit in 2002.

It was only in the past couple of years that Mr. Yondorf retired from his volunteer efforts with the group, Frisbie said.

“He was such a friend of the river that even when he was volunteering less in his office, he still came to the office, and he and (his wife) Lisa came to events and volunteered for smaller things,” Frisbie said.

Mr. Yondorf also worked as an information officer for the Chicago Tourism Council, advising visitors on city attractions and activities in English, German and French. He was also an accomplished photographer, filmmaker and expert on architecture.

Mr. Yondorf is survived by his wife, Lisa; son, David; daughter, Miriam; and granddaughter, Atara. A memorial service was held this past weekend.

Adam Harrington, CBSChicago.com