Challenge
Washington County faced an urgent problem when a failing culvert on Sullivan Road led to a road closure for emergency repairs. The existing structure not only disrupted travel but also presented risks to the Burgholzer Creek watershed, where issues like stream aggradation were impacting both infrastructure reliability and aquatic habitat. The County needed a long-term solution that would meet hydraulic and environmental requirements while minimizing impacts to the surrounding community.
Solution
Our team partnered with Washington County to provide expert culvert design and construction support for the culvert replacement. Kittelson conducted a hydrologic and hydraulic study, considering factors like stream aggradation. Field data, including pebble counts by Washington County environmental staff, informed the design. Using this data, our team developed the culvert design and placement of large woody debris to improve habitat and stream stability. HEC-RAS 2D modeling was applied to predict hydraulic performance and scouring actions to ensure that the new structure would be efficient, resilient, and passable to fish.
The Outcome
Designing a Resilient, Fish-Passable Culvert for Sullivan Road
The replacement of the Sullivan Road culvert has provided Washington County with a reliable structure that not only restores roadway function but also supports long-term watershed health. By combining hydraulic modeling, environmental considerations, and construction support, the project delivered a solution designed to withstand natural forces, improve fish passage, and meet regulatory standards. The result is an infrastructure improvement that strengthens the balance between community needs and environmental stewardship.
