Ohio wetlands began forming about 1-2 million years ago, when large ice masses began to move toward Ohio from the north. This era is known as the Pleistocene epoch, and shaped Ohio until aproximately 14,000 years ago. These ice masses ran from what is now Cincinnati to Youngstown, and covered Columbus. When the snow and ice melted, large pockets cut by ice became small kettle lakes, and streams and rivers were carved by runoff water. Many bogs and swamps across Ohio were created by this process.
Wetlands play an important role in the purification of groundwater and flood control.
Plants, algae and bacteria in wetlands can process limited amounts of toxic, man-made runoff, such as oil and gas remnants, which drain from roadways and parking lots. Wetlands also reduce flooding by acting as reservoirs in times of heavy rainfall, and they reduce erosion by holding soil in thick vegetation mats. This erosion control is particularly important near rivers, lakes and coastal areas. The wetland habitat highlights the entire ecosystem and stresses the interdependence of each organism within the system.