The Stevens Twin Sinks Karst Preserve is owned and managed by the Michigan Karst Conservancy, Inc. The MKC's purchase of the properties were made possible by the generous donations of Bill and Archie Stevens, Edward Bruski and members of the MKC.
The objective of the Michigan Karst Conservancy is to protect karst areas in Michigan and to educate the public about the value of karst lands and the safe and proper use of these lands.
One aspect of this objective is to provide educational trails on its karst preserves. These trails are narrow footpaths that often go through wet or muddy areas; across or around rocks and boulders; and often have steep, narrow, hilly, or sideways tilted surfaces. Some cross bare rock or cross a stream on a narrow rustic bridge.
These trails are not suitable for personal assistance mobility devices such as walkers, manual or motorized wheelchairs, power scooters, golf carts, off-road or all-terrain vehicles. Use of such equipment on MKC trails is not reasonable and is likely to do damage through soil erosion, trail widening, plant and root damage, and is thus prohibited.
Visitation to MKC preserves is at the visitor's own risk. MKC normally will not have staff or volunteers or emergency phones or equipment present at a preserve. The preserves are a significant distance from emergency medical facilities. Cell phone coverage is limited or non-existent, especially in the Upper Peninsula.
Two self-guided trails are located on the preserve. One trail generally follows the perimeter of the sink holes with a side spur to interesting earth cracks. This trail is unmarked but obvious. The second trail is found off the spur trail and takes visitors through woods and meadows. It is marked with yellow and red flagging.
This trail starts immediately behind the kiosk and runs counterclockwise around the sinks and returns the visitor to the parking area.
The sinks are collapse sinkholes formed in a stack of Devonian limestone and shale called the Traverse Group. Below the Traverse (800 feet) is the Detroit River Group, most of which is limestone but also contains some gypsum and anhydrite, both minerals that dissolve in water much faster than limestone. The collapse of the Traverse Group into the Detroit Group led to the creation of the sinks. The sinkholes are now intriguing geological features and unique habitats for some plants not found locally at the surface. Geological and biological studies are being conducted on the Preserve.
Be sure to follow the mowed pathway about 200 feet down the trail and leading to the right. This spur leads to earth cracks. The cracks are indications the sinkhole is slowly continuing to collapse and the surface is sliding toward the sinkhole. Someday, the sinkholes will be much wider.
Do not descend the sinkholes, in order to prevent erosion of their walls. (Note: Reascending requires technical climbing skills.) Please also "take nothing but pictures; leave nothing but footprints." Anything thrown into the sinkholes can damage natural features, or contaminate groundwater. Stay back from the sinkhole edges, in order to prevent erosion or accidents. Be especially cautious with children.
This trail begins at the earth crack spur mentioned above and is flagged with red and yellow flagging tape.
Monthly, beginning in April, the trail is mowed by MKC volunteers to make walking easier.
The trail takes hikers through some interesting areas.
One will be observe a farm field that has been abandoned and is beginning to return to a wooded area. Look for a clump of trees where there is a large central tree with a ring of young trees seeded by the central tree. You will find a very pleasant beech grove on your walk.
The trail rejoins the sinkhole trail and follows to the right past a large flow channel that diverts spring run-off from the upper farm fields into the sinkhole.