Editing Hamilton, Ohio (section)

===1913 flood===
[[File:1st National Bank Building (16772859777).jpg|thumb|The Great Flood in Hamilton, at left is North 3d Street]]
Geographic and geological evidence shows that floods have occurred throughout the valley since prehistoric times. Since European-American settlement, diaries, anecdotes, folk tales, letters, and official records have provided documentation of relatively common severe floods in 1814, 1828, 1832, 1847, 1866, 1883, 1897, 1898, and 1907.

In March 1913, the greatest flood occurred in Hamilton.<ref>{{Cite web |last=Silver Jackets |title=The Great Flood of 1913. Community Profiles: Hamilton, Ohio |url=https://mrcc.purdue.edu/1913Flood/communities/hamilton |access-date=August 15, 2024 |website=Midwestern Regional Climate Center}}</ref> Heavy rain fell over the entire watershed, and the ground was frozen as well as saturated from previous lighter rains. This resulted in a high rate of run-off from the rain: an estimated 90% flowed directly into the streams, creeks, and rivers. Between 9 and 11 inches (23 to 28&nbsp;cm) of rain fell over five days, March 25 to 29, 1913. An amount equivalent to about 30 days' discharge of water over [[Niagara Falls]] flowed through the Miami Valley during the ensuing flood. In the Great Miami River Valley, 360 persons died, about 200 of whom were from Hamilton. Some drowned, some were washed away and never found, others died from various diseases and complications, and some committed [[suicide]] because of severe losses. Damage in the valley was calculated at $100 million, the equivalent of $2 billion in 21st-century value. The flood waters were so powerful that within two hours they destroyed all four of Hamilton's bridges: Black Street, High-Main Street, Columbia, and the CH&D railroad.

In Hamilton, the flood waters rose with unexpected and frightening suddenness, reaching over 3 to 8 feet in depth in downtown, and up to 18 feet in the North End, along Fifth Street and through South Hamilton Crossing. The waters spread from D Street on the west to what is now Erie Highway on the east. The waters' rise was so swift that many people were trapped in the upper floors of businesses and houses. In some cases, people had to escape to their attics, and then break through the roof as the waters rose even higher. Temperatures hovered near freezing. The water current varied, but in constricted locations it raced at more than 20 miles per hour. Dead people, more than 1,000 drowned horses, other drowned livestock and pets, and sewage tainted the water. Nearly one-third of Hamilton's population (10,000 of 35,000) was left homeless and displaced. Thousands of houses were destroyed by the flood; afterward, many were too damaged to repair had to be demolished by city workers.
[[File:Pontoon Bridge Wrecked (16989462761).jpg|thumb|Wrecked pontoon Bridge]]
Following the 1913 flood, residents realized that the only way to prevent future flooding was to deal with protection on a [[Drainage divide|watershed]] basis. Citizens from all the major cities in the Miami Valley—[[Piqua, Ohio|Piqua]], [[Troy, Ohio|Troy]], [[Dayton, Ohio|Dayton]], [[Carlisle, Ohio|Carlisle]], [[Franklin, Ohio|Franklin]], [[Miamisburg, Ohio|Miamisburg]], [[Middletown, Ohio|Middletown]], and Hamilton—gathered together to find a solution and worked with legislative representatives to draft enabling legislation to create the [[Miami Conservancy District]]. The legislation was passed by the state and signed into law by Governor [[James M. Cox|James Cox]]. The Miami Conservancy District withstood several legal challenges, and by 1915 it hired an engineering staff to develop plans for valley-long channel improvements, [[levees]], and storage basins to temporarily retain excessive rains. The system was designed to withstand rains and flows that would be up to 40% greater than those of the 1913 flood. It was completed in 1923. Since then, the system has retained excess water more than 1,000 times, thereby preventing flooding. The Miami Conservancy District was the first of its kind in the nation and has been an example of flood control protection. It is unique for having been developed, built, and supported financially just by those who benefit. The Miami Conservancy District is financially supported by an assessment on each property that was affected by the 1913 flood, related to the present value of the property because it is not at risk of flooding. All the other areas within the District are assessed because they benefit by reducing or eliminating danger to infrastructure, commerce, and transportation.