A wetland is just what it sounds like: land that’s either covered by or saturated with water for at least part of the year.
Wetlands, particularly small ones, occur all across Cook County, often within larger prairies and woods. Many occur along rivers and other low points, while others are perched on higher ground.
Most of the region’s largest wetlands have been drained, dredged or filled. The Calumet region in southeast Cook County was famed for the wetlands around Wolf Lake, where hunters would come to hunt the plentiful waterfowl. Small remnants of these wetlands survive in places such as Eggers Grove and Powderhorn Marsh and Prairie. At the Skokie Lagoons, canoeists now paddle over what was once one of the region’s largest and richest marshes, before it was excavated in the 1930s to create the recreational lagoons we know today. A large wetland once occupied the Sag Valley in Palos Hills, where the Cal-Sag Channel now cuts through. It has since been reshaped to form the channel and Saganashkee Slough.
There are nonetheless many types of smaller wetlands in the forest preserves, and the Forest Preserves is in fact restoring many wetlands by disabling the tiles that farmers once used to drain them. A few notable varieties include:
Marshes. Usually a permanent body of water, surrounded by and interspersed with vegetation. A hemi-marsh has an equal amount of open water and plants, creating sheltered nooks for waterfowl to nest.
>>>See it at Eggers Grove in Chicago; Powderhorn Marsh and Prairie in Chicago; Paul Douglas Preserve in Hoffman Estates; Deer Grove in Palatine; Crabtree Nature Center in Barrington Hills; Cranberry Slough Nature Preserve in Willow Springs; Sand Ridge Nature Center in South Holland; Baker’s Lake Younghusband Prairie in Inverness.
You Know You’re in a Wetland When:
- Your boots are wet or you can see standing water.
- Plants are growing in the water, and some of them may be sticking out (called emergent vegetation).
- You see or hear wetland birds such as ducks, pied-billed grebes, sandhill cranes and marsh wrens.
Sedge meadows. Sedge meadows are wet, open, sunny fields where sedges, a grasslike plant, dominate. Sedge meadows in the forest preserves are often near streams, lakes or other wetlands.
>>>See it at Spring Lake Preserve in Barrington Hills; McMahon Fen Nature Preserve in Palos Hills; Spears Woods in Hickory Hills.
Ephemeral or vernal ponds. This appears for only a short time each year, usually just a month or two in spring, depending on rain and snowfall. Because predatory fish can’t survive there, ephemeral ponds are ideal places for amphibians to breed.
>>>See it at Somme Woods in Northbrook; Harms Flatwoods in Glenview; Swallow Cliff in Palos Park; Ned Brown Preserve in Elk Grove Village; Deer Grove in Palatine.
Fens. A rare wetland type distinguished by its alkaline, mineral-laden water. The water in a fen percolates through limestone and emerges as a seep, or spring.
>>>See it at Bluff Spring Fen in Elgin; Dan McMahon Woods and Fen in Palos Hills; Sagawau Environmental Learning Center in Lemont.
Did You Know?
- Almost 90 percent of the wetlands in Illinois were drained for agriculture and development.
- Land managers are bringing many wetlands back by breaking up the drain tiles farmers once installed. Soon after the water reappears, so do many of the plants and animals that once relied on it.
- Wetlands help prevent flooding of streets and homes.
Bogs. A bog is an acidic wetland with very low oxygen. Usually found farther north, bogs are home to distinctive plants such as sphagnum moss.
>>>See it at Cranberry Slough in Willow Springs.
Wooded wetlands or swamps. A wooded or forested area with significant areas of standing water. Listen for wood ducks and tree frogs.
>>>See it at Eggers Woods in Chicago; Salt Creek Nature Preserve in LaGrange Park.
Read more about the ecosystems of the Forest Preserves of Cook County: