August August 30, 2013 Sinkhole Lakes Erosion Control Pigeon River Country State Forest, Otsego County, MI Registration required. Located in the natural and wild Pigeon River Country State Forest are a series of sinkhole lakes. In the past, these lakes were closed to fishing for research. Recently, several of these lakes have been stocked with coldwater fish species to provide a unique angling opportunity. With increased traffic, shoreline erosion is increasing and poses a threat to these unique lakes. Huron Pines and the Michigan DNR are addressing unnatural erosion at Section Four, North and South Twin, and Lost and West Lost Lakes to protect the coldwater fishery in each of these rare water bodies.