Required $240K Study Forces Dubuque’s 16th Street Gate and Pump Station Project to Pause

According to a recent news release, the City of Dubuque has temporarily paused construction on the 16th Street Detention Basin flood gate replacement and pump station project. The delay comes as the Iowa Department of Natural Resources (IDNR) requires additional environmental studies before permitting the discharge of water from the site to the Mississippi River.

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The project, part of the $28.2 million Bee Branch Watershed Flood Mitigation effort, was designed to improve stormwater management and protect more than 1,300 properties from flooding. The new facility will include a flood gate, four pumps (doubling the capacity of the existing system), updated electrical service, and backup generators. Once complete, the improvements will enhance the city’s ability to manage heavier and more intense rainfall, building on the protection already established by earlier phases of the Bee Branch project.

Before the project began, the City conducted an environmental review in 2019, which received a “Finding of No Significant Impact” from the IDNR. A Local Flood Plain Permit was also issued, and the project was cleared by federal agencies, including the U.S. Army Corps of Engineers. However, in 2020, a fertilizer spill at a nearby Gavilon Grain site created a chemical plume in the groundwater containing nitrate and ammonia. The Iowa DNR monitored the clean-up at the time, and the City had no reason to believe it would affect the project.

Now, as part of a dewatering permit application, the Iowa DNR has determined further environmental studies are necessary to ensure contaminants from the spill do not enter the Mississippi River during construction. The City has hired HDR Engineering and Terracon Consultants to conduct these studies, which are expected to take several months (up to 7), at an estimated cost of $240,000.

While construction is on hold, city officials say the project remains a key step in protecting Dubuque residents and enhancing the resilience of the Bee Branch Watershed system.