Tricon completed this very technically difficult project for the City of Dubuque. The Railroad Culverts Project is a critical phase of the larger Bee Branch Watershed Flood Mitigation Project and will increase the flood mitigation system’s capacity to protect the area from a 75-year rain event to a 500-year rain event. The railroad culverts project involved using micro-tunneling methods to install six, 8-foot diameter culverts under the Canadian Pacific Railway (CP) tracks along Garfield Ave. This will allow stormwater to drain more efficiently from the Upper Bee Branch Creek to the Lower Bee Branch Creek and 16th St. Detention Basin. The six steel culverts were installed under the CP Railroad tracks while the trains remained operational. A jacking system was constructed below the Bee Branch water basin and the culverts were installed by boring 200’ long tunnels 20’ under the railroad. Each pipe required considerable prep work including cutting the holes through the sheet pile walls to allow the micro-tunneling machine to pass.
Upstream and downstream connections were also built. These included a large buried concrete transition structure south of Garfield Ave. where water from the creek and the 22nd St./Kaufmann Ave. storm sewer system comes together before entering the newly installed pipes. Downstream, a structure was built to transition water from the pipes into the creek as well as a pumping station and gate to control the water level of the upstream creek and storm sewer.
This project took 2.5 years to construct.
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