What is a Sinkhole Lake?
Sinkhole lakes are a common feature of regions with karst topography, which are areas with soluble rocks like limestone, dolomite, or gypsum. As water seeps into the ground it slowly dissolves those materials, leaving behind open spaces surrounded by more resistant stones. This tends to form cave systems, and sometimes the roofs collapse and expose the cavern at the surface, resulting in a sinkhole or sinkhole lake. The sinkhole lakes here range from about 10’ deep to almost 60’ in Hemlock and Section 4.
Because such lakes typically lack freeflowing inlets or outlets, the ones here in the Pigeon River Country were ideal for fisheries research. Many experiments that contributed to improved fishing throughout Michigan were conducted in the lakes, such as testing survivability of Assinica strains of Brook Trout before they were introduced to lakes across the state. The research ran from the 1940s to the early 2000s, and in 2008 seven of the sinkhole lakes were opened to the public for fishing and other recreational use, under strict
regulations to prevent damage to the lakes.
Recreational Guides at the Sinkhole Lakes
Section 4, Ford, Hemlock, and all four of the Lost and Twin Lakes are stocked annually with trout and operate under Type D regulations (daily limit one, minimum 15” length, artificial lures only; the season runs from the last Saturday in April through September). The unique features of the lakes require special protections for boating and camping in their vicinity. Camping within 600 feet of the sinkhole lakes is prohibited. Both of the Twin Lakes, Section 4 Lake, and (East) Lost Lake do not allow boats of any kind, although swimming and personal flotation tubes are permitted. On Hemlock Lake, Ford Lake, and West Lost Lake visitors can also use non-motorized watercraft, or boats with an electric motor.