Great Black Swamp

• Category: Inland Aquatic Biomes.
• Geographic Location: North America.
• Summary: An ancient wetlands ecosystem in the heart of North America, this biome underwent near-total undoing by human effort; today, attempts are underway to return some of these lands to their primeval condition.

At one time, the Great Black Swamp was one of the largest wetlands in the northeastern state of Ohio. That ecosystem sustained old-growth forests and habitats for many mammals, reptiles, amphibians, fish, and migratory and nonmigratory birds. It was drained by settlers in the mid-1800s to create roadways and farmlands. Currently, conservation efforts are underway to reclaim some of this lost wetland acreage and to restore—or re-create—some of the preexisting habitat.

Geography and History

The Great Black Swamp was a wooded wetland formed during the Pleistocene Epoch, when the glaciers of the Wisconsin Glacial Episode began to melt and retreat, some 12,000–20,000 years ago. Before the glaciers melted, their advancing movement and the enormous weight from over a mile of vertically packed ice scraped and scoured the land here into a relatively flat plain. The melting and retreating of the glaciers deposited vast amounts of water, leaving behind many lakes in the basins of the scraped plain.

These lakes eventually subsided, and the flat, flooded plain evolved into a massive, woody swamp dotted with intermittent wet prairies and savannas. The subsiding lakes also left behind sandy ridges and low moraines (accumulations of soil and rock left by glaciers) that acted as natural wetland borders. Clay sediment at the bottom of the lakes made a natural water-holding area, as clay is fairly impervious to water.

The Great Black Swamp was one of the largest wetlands in the region that became Ohio, stretching approximately 30 to 40 miles (48 to 64 kilometers) in width and 120 miles (193 kilometers) in length. Its borders were within the watersheds of the Maumee, Auglaize, and Portage Rivers in northwestern Ohio. The area it covered arced from Sandusky, Ohio, bordering Lake Erie in the east, to Findlay, Ohio, in the south, and Fort Wayne, Indiana, in the west. It was home to Indigenous Americans and farmers who worked the flood plains of the Maumee River and its tributaries.

To most of the first European settlers, the area was a dark, forbidding quagmire with huge trees, bottomless mud holes, putrid marshes, and heavy infestations of mosquitoes. Tribes of Indigenous People, specifically the Ottawa, lived at the edges of the swamp until they were forced out by White settlement. The tribe members would not enter the forbidding swamp themselves but instead hunted along its perimeter. The Ottawa conquered the mosquito problem in several ways. Their lodges were built with holes in the top, and a fire could burn inside; the smoke kept the mosquitoes at bay. The Ottawa also fabricated an insect-repelling rub. They typically wore long-sleeved garments and hunted mainly in winter when insects were mostly dormant. Before the arrival of Europeans, Indigenous peoples did not suffer from malaria.

Draining the Swamp

Settlement incursion into the area began in the 19th century, with the building of three main roads through the swamp. In 1808, the Western Reserve Road, now U.S. Route 20, stretched from Fort Meigs (now Perrysburg) to Findlay. General William Hull, on his march to Detroit during the War of 1812, blazed a trail through the swamp known as Hull's Trace, now U.S. Route 25. The third road stretched from Fort Meigs to McCutchenville; the “worst road in the nation,” as it became known, was this Western Reserve road. It was so atrocious that travelers considered themselves fortunate to travel a single mile (1.6 kilometers) in a day.

The decision to drain the swamp began with the building, in the 1850s, of a road through the very heart that ran from Fremont, Ohio, to Detroit, Michigan. Initially, road construction was difficult due to erosion until the engineers used rock beneath the road to level it. To allow for drainage, a ditch was placed on each side of the roadway. Culverts were placed beneath the roads to allow the water to be channeled to its natural drainage direction. Once the surface water was eliminated, the subsurface water that created seemingly bottomless mud holes was next. Draining the groundwater was performed by installing special clay tile drains buried 2 to 3 feet (up to 1 meter) below the surface, which carried the water to natural and man-made streams and onto Lake Erie.

Ironically, the Great Black Swamp held the source of its own demise. The layer of clay beneath the topsoil was 60 to 200 feet (18 to 61 meters) thick; this rich resource provided the clay mills with the necessary raw materials to fabricate the clay drain pipes used in the draining process. In 1892, machines were invented that could create the ditches faster than manual labor; the draining process accelerated. Within a few decades, the Great Black Swamp that had stood unscathed for millennia was all but gone.

Impact and Conservation

The disappearance of the swamp occurred at a faster rate and left fewer traces than the demise of any other ecosystem in Ohio; it happened so fast that a systematic inventory of flora and fauna species had not been undertaken. Not only was the water removed, but also the forest. Before the draining and tree removal, the swamp was home to a wide diversity of deciduous trees such as elm, black ash, sour gum, silver and red maple, pin oak, swamp white oak, sycamore, white ash, buckeye, shellbark hickory, honey locust, black cherry, and yellow and red oak. These trees and their stumps were all removed to pave the way for agricultural fields. Gone were the many varieties of trees and ground plants, along with the wildlife habitats they supported. Gone, too, were countless unknown mammal, amphibian, reptile, insect, and avian species.

The draining of the Great Black Swamp and its subsequent transformation into farmland also had unintended consequences. Wetlands act as an environmental buffer in an ecosystem. They slow soil erosion and filter harmful agricultural runoff such as herbicides, pesticides, and fertilizers before they reach streams, rivers, and lakes.

The water from the Great Black Swamp was now free to travel downstream, where it accumulated in Lake Erie. These nitrate-rich deposits from fertilizers accelerate the growth of algae in Lake Erie, creating vast blooms that deplete oxygen in the water, resulting in massive fish kills. According to the Environmental Protection Agency (EPA), 90 percent of Ohio's wetlands were lost with the destruction of the Great Black Swamp, to the detriment of towns downstream and ultimately to the Lake Erie ecosystem. Flood damage, increased drought, invasive weed and insect populations, and a declining avian population were among the negative direct impacts associated with the disappearance of the Great Black Swamp.

State and national government agencies, private landowners, and nongovernmental organizations such as Ducks Unlimited and the Black Swamp Conservancy (BSC) have realized the importance of wetlands. These organizations and individuals are working to transform some of the land back into much-needed wetlands. The BSC had transformed 11,000 acres (4,046 hectares) back into a marsh by 2022, with a professed goal of adding 1,000 acres (405 hectares) each year. In 2024, the BSC donated 160 acres to Seneca Parks after having completed the restoration work to the Clary Boulee McDonald Nature Preserve. It was the largest restoration project the BSC had undertaken to date. BSC continues to work on restoring the Black Swamp. The eventual and ongoing goals are to prevent agricultural runoff, to free some wetland water flow, and to re-create lost habitats for mammals, insects, reptiles, amphibians, fish, and birds.

Bibliography

"160-Acre Clary-Boulee-McDonald Preserve Becomes Seneca County Park." Black Swamp Conservancy, blackswamp.org/160-acre-clary-boulee-mcdonald-preserve-becomes-seneca-county-park/. Accessed 3 Nov. 2024.

Hallett, Kaycee. "History of the Great Black Swamp." The Black Swamp Journal, 14 Apr. 2011, blogs.bgsu.edu/blackswampjournal/2011/04/14/history-of-the-great-black-swamp. Accessed 3 Nov. 2024.

Light, Christopher. "Draining the Great Black Swamp." The Historical Marker Database, 7 Dec. 2007, www.hmdb.org/Marker.asp?Marker=4025. Accessed 3 Nov. 2024.

Platt, Carolyn V. "The Great Black Swamp." Timeline, vol. 4, no. 1, 1987, pp. 18-29.

Stimson, Ashley. "The Death and Life of the Great Black Swamp." Belt Magazine, 27 May 2022, beltmag.com/death-life-great-black-swamp/. Accessed 3 Nov. 2024.