MIAMI VALLEY — Up to three-quarters of an inch of rain combined with snowmelt has raised the Great Miami River in Dayton and Hamilton nearly 6 feet from normal for this time of year. 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. Storage begins when the water levels rise to the top of the conduits (concrete openings) at the dams.
The conduits allow only the amount of water through that the downstream channel can handle. The remaining floodwaters are held in the retarding basins (land behind the dams) and will drain out over the next several days. Storage at all of MCD’s dams except Englewood is expected to crest today. Englewood storage is expected to crest Friday night/Saturday morning.
MCD staff continues to monitor river levels and take action as necessary. Staff closed storm sewer floodgates in Troy, Middletown and Hamilton last night and early this morning. Cities have storm sewer pipes running through MCD levees that drain city streets to the river. Floodgates built at the end of storm sewers remain open except when they are closed to prevent a rising Great Miami River from backing up into the storm sewer and into 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 1,950 times since their construction. The levees keep floodwaters within the river channel through the riverfront communities of Piqua, Troy, Tipp City, Huber Heights, Dayton, Moraine, West Carrollton, Miamisburg, Franklin, Middletown and Hamilton.