Cold Water Resource Threat: A measure of vulnerability of Great Lakes watersheds to thermal loading, based on the most influential factors that shape thermal conditions: mean annual air temperature, groundwater discharge potential, surface water extent, and riparian forest cover (weighted and used to develop an environmental index of aquatic resource sensitivity or vulnerability to thermal loadings).The product of the thermal vulnerability and the miles of coldwater streams in a given watershed (mean July temperature of 75 received a score of 1.00. The scale then breaks down as follows: 0.00 = High Threat, 0.33 = Moderate Threat, 0.66 = Low Threat, 1.00 = Extremely Low Threat