Timmes, a 1992 VMI graduate, is a professional engineer who served for over 25 years in the U.S. Army Medical Service Corps and is a professor in the VMI Civil and Environmental Engineering department. As a volunteer diving coach, the VMI men's and women's teams have grown to a squad of nine divers, a record number for the team in recent years. Timmes swam and dove in the Northern Virginia Swim League and was a four-year letterman and team captain (Diving) at Hayfield Secondary School in Alexandria, Virginia. Upon entering VMI, he dove during the 1988-89 season and finished the season as the Tri-State Champion for both the 1 Meter and 3 Meter diving boards. His "rat" year total score for 11-dives on the 1 Meter board remains in the VMI record books. Timmes coached his former hometown summer diving team and has consistently served as a diving judge in Division 1 competitions and invitational meets.
As an Army Environmental Engineer, he conducted extensive drinking water and wastewater system characterizations and public health threat assessments throughout the U.S. and overseas in Macedonia, Uzbekistan, Kazakhstan, Italy, Germany, and Norway. He commanded the Headquarters Company of the U.S. Army Chemical Activity-Pacific on Johnston Atoll during its closure as a chemical agent demilitarization site and served as a Jumpmaster with the 82d Airborne Division. He taught a variety of academic subjects on the faculty at the US Military Academy (West Point) for six years. Timmes commanded the U.S. Army Center for Environmental Health Research in Fort Detrick, Maryland, and served as the Director for Environmental Health Sciences and Engineering at the Army Public Health Center before retiring from Active Duty to join the VMI Civil and Environmental Engineering Department.