Stream sediments often play an important role in regulating phosphorus (P) concentrations in stream water. The purpose of this study was to evaluate sediment – water column P relationships in streams within the Rathbun Lake watershed in southern Iowa, specifically targeting four representative creeks. A second objective was to evaluate the relationship between sediment properties and calculated indicators of P loss risk to determine whether environmental risk can be predicted. Stream water samples collected from the watershed indicated that both median dissolved P (DP) (0.07 mg L^-1) and total P (TP) (0.24 mg L^-1) concentrations were high relative to proposed nutrient standards, suggesting that some form of remediation is necessary to improve water quality in Rathbun Lake. When evaluated by Mehlich-3 extractable P and degree of P saturation (DPS), stream bank and bed sediments had low risk of P loss. However, equilibrium P concentration (EPC), which ranged from 0.02 to 0.12 mg L^-1, indicated that some bed sediments could release P to water depending on DP concentrations in the stream water column and the time of the year. The likelihood of P desorption from the sediments increased with increasing pH (r = 0.92, p < 0.01) and sand content (r = 0.78, p < 0.05), but decreased with Fe (r = -0.93, p < 0.001) associated with organic matter. Based on  proposed nutrient criteria value for streams (0.04 mg P L^-1), results suggest that changes in land use within the riparian areas may, at least initially, have little effect on P loads in the streams leading to Rathbun Lake.