Bill Downing wanted to spend the longest day of his ebbing life at the lake.

The promise of one last summer solstice party at Wabana Lake near Grand Rapids, Minn., kept the World War II veteran fighting to live, friends and family say.

Downing initiated the annual tradition at his waterside home five years ago to cultivate a community as passionate about the lake’s longevity as he was. Canceled one year because of Downing’s waning health, the celebration resumed on June 21, also Father’s Day.

Downing, who had many titles — husband, father, grandfather, scientist, professor, author and advocate of the natural world — died a month later, on July 21, of ­kidney failure and infection. He was 93, and also had lived in Falcon Heights.

“One of his goals was to get back to the lake and see his friends there,” said his son, John Downing. “And he made it.”

Those sandy shores had given rise to a life of love for and learning about nature.

The Wabana Chain of Lakes, an asset of Downing’s family for more than a century, is where he met and befriended his future wife, Betsy Meader, when they were kids. After the war and their wedding, they spent the summers there, kayaking and canoeing with their three children. Together, they created a community committed to protecting the lake and its surrounding forests.

“His [solstice] tradition always had the undercurrent of making sure there was as good of water three generations forward as there is now,” John said.

In his final weeks of bed rest, the insatiable learner read the suspense novel “Seed” and Science magazine, while also compiling the final segments of a book based on ­wartime letters he exchanged during his early 20s.

William L. Downing was born in Des Moines, attended ­Roosevelt High School in Minneapolis and spent every summer romping around Wabana Lake with his brothers. He earned his bachelor’s degree at Drake University in Des Moines in three years.

“He was a little bit of a Renaissance man,” said Libby Colburn, his youngest daughter. “He just knew all kinds of stuff about all kinds of things.

Seldom a complainer, Downing relished in the simplicities of nature, drank bourbon every evening, and enjoyed baking angel food and sour cream poundcake.

He confessed to his son shortly before his death that he was reluctant to have missed two summers at the lake: one because of illness, the other because of the war.

Downing joined the U.S. Navy in 1943, heading overseas to fight in WWII. Because he had studied French, he worked with the Free French Navy. After the battles of Saipan and Okinawa, Downing was among the first to land at Nagasaki after an atomic bomb was dropped on that city — the second dropped on Japan by the U.S.

“He never expected to come back,” John Downing said, “and so the rest of his life was a gift.”

A colored portrait of Betsy traveled across the ocean with Downing, as did the letters they exchanged. Unable to get leave, he proposed through the mail in 1944 after passing an engagement ring through a train window to a friend to get to her. They were married for 60 years, until Betsy’s death in 2006.

“My parents, I think, built their love around a love for this beautiful environment in northern Minnesota,” John said. “It was sort of a center for what they were like as a couple.”

After completing master’s and doctorate degrees, Downing shared his passion for biological sciences with generations of medical students. He taught at Hamline University in St. Paul, where he was later named a professor emeritus, and published several papers for the journal Nature. Outside of academia, he founded the Ramsey County Soil and Water Conservation Commission.

Into his 80s, Downing served as president of the Wabana Chain of Lakes Association. He was succeeded by John Zimmerman, who said of him: “He wouldn’t ever try and stop change, but he wanted people to be a little more gracious about [land] use. He just made you think about it.”

Memories of Downing will be shared next year at the summer solstice party. “We are definitely going to continue on the tradition,” said his daughter-in-law, Marcia Downing. “Forever,” John, her husband, chimed in.

In addition to son John and daughter Libby, Downing is survived by another daughter, Deborah Gelbach; four granddaughters; and three great-grandsons.

A memorial service will be held at 3 p.m. Aug. 29, at Unity Church, 733 Portland Av., St. Paul.