The one-dimensional numerical model developed by Carl R. Goodwin is applied to the Siuslaw estuary. Vertical displacement, horizontal velocity and flow of the water as a function of time and distance from the mouth given by the model are compared with field observations taken under different water mixing conditions in the estuary. The model is considered adequate under well mixed and partially mixed conditions, and inadequate under strongly stratified conditions. Estimations of deviations between model predictions and field observations are presented. Nomograms are constructed from model predictions of amplification factors, high water time lags, maximum flood velocities, maximum ebb velocities, low water time lags, maximum flood flows, maximum ebb flows, high slack water time lags and low slack water time lags, as a function of river flow, ocean tidal range and river mile for a range of 0 to 6000 cubic feet per second (0 to 170 cubic meters per second) of river flow, and 1 to 11 feet (0.30 to 3.35 meters) of ocean tidal range. These nomograms are considered adequate for predictive purposes during well mixed and partially mixed conditions of the estuary waters. / Graduation date: 1975