AbstractThis paper shows that the river water quality problem can be formulated and solved using the CSMP and DYNAMO simulation languages. In CSMP, a continuous solution approach is adopted while DYNAMO follows a finite-section solution, which assumes that water quality remains constant in each section. Application of the CSMP and DYNAMO formulations to the Hsintien River in Taiwan indicates that they can produce acceptable results as compared to available measured data, and those obtained from CSMP seem to provide a better fit.