This report presents the total maximum daily load (TMDL) for phosphorus for Osage Creek downstream of Berryville (stream segment 11010001-045L), which is located in the Kings River basin in northwest Arkansas. This stream segment was included on the Arkansas final 2002 Section 303(d) list (Environmental Protection Agency (EPA) 2003) for not supporting its aquatic life designated use (Table 1.1). Phosphorus is listed as the suspected cause of this impairment in the 303(d) list. According to the Arkansas Department of Environmental Quality (ADEQ) 2002 integrated assessment report (ADEQ 2002), the suspected primary source of elevated phosphorus concentrations in Osage Creek is the Berryville municipal wastewater treatment plant (WWTP). The purpose of a TMDL is to determine the pollutant loading that a waterbody can assimilate without exceeding the water quality standards for that pollutant and to establish the load reduction that is necessary to meet the standard in a waterbody. The TMDL is the sum of the wasteload allocation (WLA), the load allocation (LA), and a margin of safety (MOS). The WLA is the load allocated to point sources of the pollutant of concern and the LA is the load allocated to nonpoint sources and natural background. The MOS is a percentage of the TMDL that takes into account any lack of knowledge concerning the relationship between pollutant loadings and water quality.