At their last meeting, the Illinois Nature Preserves Commission approved the designation of the Dayton Bluffs as a “Land and Water Reserve”.
The Land and Water Reserve designation is essentially a conservation easement with the Illinois Department of Natural Resources. This designation is for lands and waters that support significant natural heritage or archaeological resources.
The unique geological, archaeological and biological resources of Dayton Bluffs qualify it for this designation. Lying in the Grand Prairie Section of the Grand Prairie Natural Division of Illinois, Dayton Bluffs was shaped by the last period of glaciation. It lies on the front of the Marseilles Moraine, one of Illinois' largest moraines, which was formed about 30,000 years ago with the expansion of ice into Illinois. As the freezing glacier was expanding south and westward, it flattened the landscape through erosion, then left ridges of glacial till called glacial moraines that trapped glacial meltwater into lakes. Sedimentarily speaking, you will find wind-blown loess over silty clay lake depoits and glacial till on top of bedrock at Dayton Bluffs, which reflects this glacial history The bluffs and ravines we see today would have been formed by pulses of glacial meltwater flowing down the Fox River after it was formed by the draining of glacial Lake Ottawa.
There have been significant archaeological findings at Dayton Bluffs as well, including 14 prehistoric burial mounds. The site lies within the Lower Fox River Conservation Opportunity Area and is one of 18 significant natural areas identified in a Native Habitat Inventory of the Lower Fox River by the Illinois Department of Natural Resources in 1999. It is also know for providing habitat for the state-threatened river redhorse (Moxostoma carinatum).
Land and waters identified as Illinois Land and Water Reserves must include the following:
* Lands and waters included on the Illinois Natural Areas Inventory.
* Habitats of State listed threatened species of animals or plants.
* Forests at least 100 acres in size that support breeding populations of area sensitive forest wildlife species.
* Grasslands at least 80 acres in size that support breeding populations of area sensitive grassland wildlife species.
* Wetlands at least 50 acres in size or an area that includes several wetlands totaling 50 acres in size.
* Degraded but restorable prairies at least 20 acres in size.
* Segments of degraded but restorable railroad prairie at least 1 mile in length.
* Areas supporting unusual concentrations of wildlife such as nesting colonies; hibernating colonies; and migration stopover, feeding and rest sites.
* Restorations of natural communities of plants and animals that existed in Illinois at the time of settlement by immigrants from Europe for which no high quality examples are known within the region.
* Areas supporting significant archaeological resources.