and last updated 2021-08-04 18:40:38-04 CHESHIRE TOWNSHIP, Mich. â The Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the Michigan Department Health and Human Services (MDHHS) warned the Allegan County Health Department (ACHD) of a suspected blue-green algae or a cyanobacterial bloom in Swan Lake. Those who visit the lake in Cheshire Township are urged to avoid water related activities and keep pets from drinking from the lake where the bloom is visible until sampling for cyanotoxin testing is complete or the bloom disappears. According to the ACHD it is impossible to determine if algae contains harmful toxins by look and in turn encourages avoiding contact with any body of water covered with algal mats.