The Soil and Water Assessment Tool (SWAT) model was used to study the Maquoketa River watershed in Iowa. Data from weather stations and streamflow measurements were used to analyze how different factors affect surface runoff and baseflow. The most important parameters for the watershed were found to be curve number, evaporation compensation factor, and soil available water capacity. The model was calibrated and validated for accuracy, showing it can predict streamflow with at least 86% accuracy for the calibration period and 69% for the validation period. This study lays the groundwork for future water quality analyses in the Maquoketa River watershed using SWAT.