HOW NORTH CAROLINA IS EFFECTED ECONOMICALLY BY WATER POLLUTION About 80% of the State’s surveyed freshwater rivers and streams have good water quality that fully supports aquatic life uses, 17% have fair water quality that partially supports aquatic life uses, and 3% have poor water quality that does not support aquatic life uses. Ten percent of the surveyed rivers do not fully support swimming. The major sources of impairment are agriculture (responsible for 53% of the impaired river miles), urban runoff (responsible for 16%), and const ....