Houston’s Addicks Reservoir is expected to spill over Tuesday for the first time in its history, amid unprecedented rainfall and flooding in the aftermath of Hurricane Harvey, multiple outlets reported. The Army Corps of Engineers reported homes upstream from the Addicks and Barker dams were beginning to flood early Tuesday. Harris County Flood Control meteorologist Jeff Lindner told Fox News that the expected spillover will “dramatically affect” nearby neighborhoods in Houston’s northwest corridor. Local ABC affiliate KTRK-TV reported that a spillover would be “uncharted territory” as the dam’s spillway hasn’t been activated in the reservoir’s 70-year history. Local outlets report the dam has been considered in “critical” condition for years and concerns have emerged about the dam’s controlled spillover function failing.