regional ice thickness regulations

Down here in region 3 , it again has been brought to my attention a local state park public hardwater requirement is at least 6" and before they even test for thickness there must be no open water on the impoundment. New York states DEC site ice displays a chart determining ice safety weight loads per ice thickness. 3 to 4 iches seems minumum requirement throughout the state but I guess the lower warmer regions along with the fact certain waters have too many underwater spring feeds along the shorelines require additional precautions. Still open water on the larger water down here.