National Park Service officials have asked the Arkansas Department of Environmental Quality to list three tributaries to the Buffalo National River on the department's biennial list of polluted water bodies in Arkansas, but so far the department has declined. The park service has asked to add Mill Creek, Bear Creek and Big Creek, but the department has argued that the data obtained during the "period of record" -- before April 1, 2015 -- don't show that the waterways are polluted.