Nephelometric turbidity and Secchi disc were measured at 16 sampling stations at Lake Carl Blackwell, Oklahoma on 54 dates from 12 February 1982 to 24 January 1983. Measurements of precipitation, wind velocity, effective fetch, water depth, and sediment particle size were also recorded. Turbidity values ranged from 16 to 1 140 NTU and Secchi disc transparency from 2 to 110 cm. Turbidity was generally highest at shallow water sampling stations in the western end and upper arms of Lake Carl Blackwell and decreased with increasing depth. Increases in turbidity during the spring of 1982 were attributed to sediment resuspension and drastic turbidity increases were observed following heavy May rains. Two multiple regression models were developed to predict nephelometric turbidity levels for a given set of climatological and morphometric parameters. One model was based on data for the entire sampling period and is useful in predicting turbidity under high inflow conditions. A second model was derived from data collected prior to periods of heavy rains and is useful in predicting turbidity under more common conditions of moderate winds and rain.