Most of Ohio's lakes are not natural bodies of water

Reprinted from the Fall 2006 issue of Natural Ohio, a publication of the Ohio Department of Natural Resources Division of Natural Areas and Preserves. 

When is a lake not a lake? Our query may sound like the kind of riddle passed around in elementary classes, but we guarantee the answer may surprise you.

Ohio has at least 50,000 lakes and ponds worthy of those names, with more than 2,000 that cover 5 acres or more. But not all are true lakes, or at least not true “natural” lakes that were here before settlers began building farm ponds, reservoirs and canals.

In fact, aside from Lake Erie, most of the well-known recreational lakes in Ohio—the water enjoyed most for boating, swimming and fishing—are definitely man-made. Virtually all are reservoirs, held back by dams and built for water supply or flood control where no lake existed before.

Just where are the true, natural lakes in Ohio? How many are there and how can you tell the difference? That’s where the answers get tricky, for even the experts don’t always agree.

Glacial lakes

Geologists with the Ohio Department of Natural Resources say there are two types of natural lakes in Ohio. First are the glacial and kettle-hole lakes, both types were created thousands of years ago when glaciers moved out of Ohio and left behind a trail of melting ice. Think of them as large, Ice Age puddles, left behind mostly in northern Ohio where glaciers once reigned.

Lake Erie is of course Ohio’s grand champion glacial remnant, followed in size by 385-acre Chippewa Lake in Medina County. Perhaps Ohio’s best known and best preserved inland glacial lake is the 100-acre beauty at Punderson State Park in Geauga County. While so many of Ohio’s glacial lakes have disappeared over the past two centuries—filled in or drained as the state was settled—Punderson has remained an open body of “natural” water. What ancient glaciers left behind, modern-day Ohioans can enjoy today.

Other glacial lakes have been lost over time to natural processes that transformed them into something quite different: glacial bog meadows. One fascinating example, still in transition, is Triangle Lake Bog State Nature Preserve. While some of the ancient lake remains, you can clearly see how vegetation is slowly closing in on the open water. This nature preserve protects one of the finest and least disturbed kettle-hole bogs in Ohio, supporting a wide variety of unique plants. Nearby, Kent Bog State Nature Preserve is what Triangle Lake Bog will become—a completely filled-in bog meadow. Both Portage County sites feature tamarack trees, another remnant of Ohio’s Ice Age.

Oxbow lakes

The second type of natural lake in Ohio is more likely to be found in southern counties, although few and far between. These are oxbow lakes, formed when a bend in a winding river becomes separated from the main flow—either by floods or erosion—then was left on its own as a free-standing body of water. These lakes are neither large nor long lasting, therefore most of them remain unnamed.

Many would be surprised to learn that less than three dozen of Ohio’s 50,000 lakes and ponds make the Cleveland Museum of Natural History’s list of “natural” lakes. Jim Bissell, the museum’s curator of botany, places the count at 33. He’s been helping compile a list since 1988.

Bodies of water making Bissell’s list must not only have natural origins, but must also be home to certain floating and deep-water vegetation—often these plants are rare or endangered. In some cases, these plants may be found exclusively in just one specific lake.

According to Bissell, there are other naturally occurring lakes in Ohio beyond his list of 33, but they no longer support the types of vegetation he looks for as hallmarks of these unique ecosystems. Bissell fears that Ohio’s precious few natural lakes will become fewer still, as human encroachment and invasive plant species—yellow iris, purple loosestrife and others—continue to take their toll.

— Laura Jones
Office of Communications
Ohio Department of Natural Resources