Irwin Prairie State Nature Preserve is located within the Oak Openings Region of Northwest Ohio.
Here, often found within a few feet of each other are both clay and sand-based soils. The region was covered by glacial ice during the Wisconsin period. The glacier deposited clay till and leveled any valleys or ridges making the region very flat. When the glacier melted back, about 15,000 years ago, an ice sheet blocked the eastern outlet of what is now Lake Erie. The melt waters rose and covered Northwest Ohio with a sequence of lakes and sandy shorelines. The lake that covered the Oak Openings Region was known as Lake Warren. When the lake receded, the sand was blown into dunes resting on top of the clay. The Irwin Prairie was an inland body of water 4 miles long and 1 mile wide before settlement and ditching occurred. A thin sand layer over the impervious clay below holds groundwater at or above ground level, allowing flooding conditions much of the year. This condition enables wet meadows and swamp forests to thrive among sand dunes. Irwin Prairie State Nature Preserve protects Ohio’s finest sedge meadow which is dominated by several species of sedges, rushes and wetland grasses. In 1859 the Lucas County Commissioners initiated an extensive network of drainage ditches throughout the county. Today, only 50 acres of the original Irwin Prairie still remain.
To receive credit for this earthcache you must hike a boardwalk out into the flooded area and take a measurement at the “last board” on the walk, not from the viewing deck. You will measure the distance in inches from the “top” of the board down to the water surface and report this distance to me in an email. In addition, you must take a photo (now optional) at the place you took the measurement showing your gps unit and post it with your log.
You will first pass through an Oak Savannah area giving way to a Swamp Forest dominated by pin oaks. Emerging from the forest you will be in the Wet Prairie. After the boardwalk crosses Irwin Rd the Wet Prairie really widens and opens up. Continue through another segment of Swamp Forest and arrive at a very secluded section of Wet Prairie known as Grass Lake and an observation deck.
Be alert for some of the animal inhabitants of this area. Unusual birdlife along with many reptiles and amphibians can be seen. The state endangered spotted turtle is found on a regular basis along with several other turtle species. Watch for some of the snakes; hognose and garter snakes being the most common, but Kirtland’s, ribbon and blue racers may also be seen.
The coordinates take you to the designated parking area and the beginning of the boardwalk. Along with your tape measure, camera and gps unit, I recommend carrying some water and maybe binoculars in case you spot something of interest. Open 1/2 hr before sunrise to 1/2 hr after sunset. Stay on the boardwalk at all times.
This 1 1/4 mile loop trail is wheelchair accessible however no kick rails are provided on the boardwalk so assistance is recommended.
A special thanks to the Ohio Department of Natural Resources, Division of Natural Areas and Preserves for reviewing and approving this earth cache. All proposed caches must be reviewed and approved by the site manager. Traditional geo-caches are not permitted at state nature preserves; however, virtual caches such as Earth Caches are permitted so long as visitors obey all preserve rules, which include remaining on the designated trail system at all times. For more information on Ohio's state nature preserves visit:Ohio's Preserves