Barr helped the Capitol Region Watershed District realign a section of the 100-year-old Trout Brook interceptor to make way for new Minnesota Department of Transportation highway bridges near downtown Saint Paul. BNSF Railway agreed to a rare 30-hour shutdown of two mainline tracks to allow removal and replacement of 120 feet of track, open-cut excavation, installation of 162 feet of box culvert, and backfilling. Months of planning preceded the effort. We designed a three-tiered diversion and dewatering system to accommodate lower base flows so that the stream could handle higher flows to prevent flash flooding. Challenging soil conditions, a high groundwater table, and contaminated soils and groundwater complicated site design and construction. A sophisticated track-monitoring system was installed to verify that the surrounding railway was not impacted.
During the 30-hour work window, an abandoned tunnel was discovered and removed in hours, rather than the weeks or months this would ordinarily take. A compressed schedule, coupled with unforeseen obstacles, required a rapidly evolving design that could meet changing conditions and overcome construction challenges. Working with stakeholders, regulators, contractors, and the watershed district to solve problems and overcome obstacles in real time enabled our team to minimize disruptions, allowed the highway construction project to move forward, and restored rail service on time. After conclusion of the 30-hour work window, the rest of the 800-foot tunnel realignment was completed and the old tunnel abandoned, allowing the bridge project to proceed on schedule.
Vice President Senior Water Resources Engineer
Senior Geotechnical Engineer
Vice President Senior Civil Engineer