Great Miami River

About

Great Miami River, Ohio — 1795 Treaty of Greenville, 1840s-1880s Milling, 1990s-2010s Buried Valley Aquifer 160-mi. The name comes first. The Great Miami is the ancestral homeland of the Miami Tribe, for whom both the river and the valley are named. The Miami lived in villages along the lower river for centuries. That era ended in violence: the 1794 Battle of Fallen Timbers, fought just north of the Great Miami's mouth, closed out the Northwest Indian War. The following year, the 1795 Treaty of Greenville ceded much of western Ohio to the United States and opened the valley to settlement.

Yet people had shaped this landscape long before the treaty. On the bluffs overlooking the river south of Dayton stands the Miamisburg Mound, one of the largest conical burial mounds in North America. Beneath the valley floor lies an older inheritance still: the Great Miami Buried Valley Aquifer, formed through three successive waves of glaciation during the Pleistocene Epoch, between two million and ten thousand years ago. Its highly permeable sand and gravel deposits run as thick as 200 feet, and the City of Dayton draws drinking water for 400,000 people from it. It remains the most important aquifer in southwest Ohio.

Settlement brought industry. The watershed was logged from the 1830s through the 1920s, feeding the regional timber trade and the railroad expansion of the later nineteenth century. Local sawmills, logging drives, and downstream lumber operations worked the valley until the old-growth stands were exhausted around 1910; state forestry conservation began in 1915, and state forests established in the 1930s ended large-scale cutting. The 1840s through 1880s were the milling era, and the river fed the growing economies of Sidney, Piqua, and Dayton. The first hydrological studies followed—USGS surveys in the 1870s through 1890s, gauging stations from the 1880s onward, and streamflow assessments through the early twentieth century.

Then came 1913. In March, the Great Miami and its tributaries overwhelmed Dayton, killing over 360 people and causing more than $100 million in damage. In response, Ohio created the Miami Conservancy District in 1915 and built five dry dams on the upper Great Miami—the first comprehensive flood-control system in the country. The system has protected the Miami Valley from catastrophic flooding for over a century, and its levees and dry dams still guard the cities that grew along the water.

Today the river reads in three sections. The Upper Great Miami, from Indian Lake to Piqua, is Class I rural headwaters. The Middle Great Miami, from Piqua to Dayton, runs Class I–II through urban smallmouth water. The Lower Great Miami, from Dayton to the Ohio River, is Class I and holds a stocked muskellunge fishery. The river carries three designations that capture its character: the Miami Conservancy District, the Great Miami Water Trail, and Ohio Stocked Muskellunge Water. Above it all sits the buried valley aquifer and the Conservancy District's water-treatment plants—a working river that still answers to the flood of 1913.