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Posted: November 2, 2018

Great Miami River rises 7 feet in two days

The Great Miami River in Dayton and Hamilton has risen about 7 feet in the last two days. And MCD’s flood protection system of dams and levees is working as designed, preventing floodwaters from affecting downtowns along the river from Piqua to Hamilton.

All five MCD dams – Germantown, Englewood, Lockington, Taylorsville and Hamilton – are temporarily storing floodwaters after 3 to 3.5 inches of rain fell in the past two days. Storage at the dams begins when the river levels rise to the top of the conduits (concrete openings) at the dams.

The conduits at the dams allow only the amount of water through that the downstream channel can handle and hold back the rest. It will take several days for the stored floodwaters to drain and maybe longer if the forecast for possible thunderstorms on Tuesday is accurate.

MCD staff continues to monitor river levels and take action as necessary. So far, staff has closed storm sewer floodgates in Piqua, Troy, Middletown and Hamilton. Cities have storm sewer pipes running through MCD levees. These pipes drain city streets to the river. Floodgates are built at the end of storm sewers. During high water, closing the floodgates prevents river water from backing through the sewer into the cities.

MCD’s five dry dams were all built at the same time between 1918 and 1922. Together, they have temporarily stored floodwaters more than 1,940 times since their construction.