An integrated model of the rainfall-runoff process as it applies to watersheds of Indiana is described. The model considers watershed characteristics, rainfall patterns and climatic conditions. The analysis of stream network data indicates that small Indiana watersheds obey the Strahler and Shreve ordering system. Drainage area, drainage density and basin slope are the major watershed parameters. A contributing drainage area distribution curve along the stream reaches was developed for the purpose of runoff estimation. A linear three parameter method was used to route the contributed runoff through the drainage area distribution curve. Based on the dynamic area model and the linear routing technique, a runoff simulation model is proposed. The basic input information required is the rainfall hyetograph, the base flow, the daily minimum temperature, the soil index and drainage and topographic maps. The model performance is compared with some of the other methods currently used in engineering design. (Author)