Physical Hydraulic Models:Assessment of Predictive Capabilities. Report 2. Movable-Bed Model of Galveston Harbor Entrance.

摘要

This study evaluates movable-bed physical hydraulic model predictions of sedimentation effects arising from channel realignment and deepening in Galveston Harbor entrance, Texas. Comparisons of model predictons and observed behavior for 6 years following completion of channel realignment showed that qualitative predictions of an arrest of undermining of the north jetty were correct and that the predicted relative increase in total maintenance dredging was reasonably close. The primary objective of the original study--to improve channel alignment for navigation safety--was achieved but is not addressed in this report. Detailed analysis showed that absolute model predictions of dredging volumes were somewhat low in the approach channel, essentially correct in the outer bar channel, and considerably low in the inner bar channel. Locations of scour and fill were accurately predicted for the navigation channel but volumes of the changes were underestimated by the model. Large zones of scour and fill in the entrance were approximately similar in model and prototype. Differences in model and prototype results are believed to be due to scale effects and insufficient prototype data. It is concluded that movable-bed modeling is a feasible, though difficult, technique and that steps to improve model similitude will improve similar future movable-bed model studies. (Author)