John Robert Clark

John Robert Clark passed away May 4th, 2026, at Boulder Community Hospital from a sudden and severe infection. He was 86.

Born October 23rd, 1939, in Weehawken, NJ, to parents Melvin Eugene Clark and Virginia May Hiller, John graduated from Wichita High School East in 1957. John then earned his B.S. in Civil Engineering and Business from the University of Colorado in 1964. He had an impressive career in the US Navy as a Seabee and Lieutenant serving in Vietnam, Antarctica, and Barbados.

In 1969, John married Sheryl Ann Koelling in Wichita on Valentine’s Day. He worked for various civil engineering consulting firms in water management and as an instructor at Colorado State University. In 1992, John earned his Ph.D. in Civil Engineering from C.S.U.

John was involved in community activities in both Fort Collins and later in Boulder. He was a Life Member of the American Society of Civil Engineers (A.S.C.E.); Forever Gold (C.U. Boulder); a past Board Member of the Colorado Engineer Magazine (C.E.M.); the Boulder Model Railroad Club; Boulder Country Club; and the Military Officers Association of America (M.O.A.A.).

John is survived by his loving wife, Sherry Ann Koelling Clark of Boulder, CO; his sister, Merry Sue Clark of Boulder, CO; his brothers, Walter Clayton Clark of Lafayette, CO and Dale Eugene Clark (Lynn) of Mechanicsville, VA; his daughter, Vanessa Joy Clark of Longmont, CO; his son, Matthew Lyon Clark of Crestone, CO; his grandson, Sebastian Mathews of Denver and a large extended family.

He had an inherited love of Colorado. He loved hiking The Colorado Trail and 14ers, hut trips using the 10th Mountain Division backcountry ski trails, camping, and biking all over Colorado. He also biked in the U.S., South America, and Europe. John will be remembered as an intellectual and a scholar. He was curious, had passion, and was brave with integrity. John also possessed a heartfelt determination to complete projects with planning, preparedness, honesty, and humility from start to finish. He loved the challenge and working with his hands. He was a man of many talents and many interests. John was a man who lived a remarkable life, and he is missed.

The Clark Family will hold a Graveside Ceremony at Green Mountain Cemetery (290 20th Street, Boulder, CO 80302) at 1:00 PM on Friday, May 29th, with Military Honors provided by the United States Navy. An open house will follow at Merry Sue’s residence, approximately from 2:30 – 4:30 PM. Friends and family are welcome to attend either or both.

Please consider a memorial donation to the CU Foundation (cufund.org), specifically to the Colorado Engineer Endowment OR the Forever Gold Scholarship Fund.