Alternate Title

Numerical Computations for Estuarine Flood Plains


Construction on estuarine flood plains can contribute significantly to flooding problems during times of large river inflow. A two dimensional depth averaged finite difference model is presented which allows for improved environmental impact assessment of construction on estuarine flood plains. The model is applied to the delta region above Mobile Bay, Alabama where a railroad crosses the flood plains. The railroad is built on a fill with trestles at established channels. The model is used to evaluate the effect which the railroad has on known flooding problems in the delta region. Partial calibration and verification of the numerical model is accomplished with available prototype data from previous flood events. The numerical model demonstrates that while a great amount of water may be stored on flood plains, conditions are not generally conducive for large flow rates. Most of the flood still moves along major established channels. Construction on flood plains may exert a significant influence on flood stage elevations in certain regions with other regions experiencing a very minor effect. In particular, construction in the interior of the flood plains may produce large effects in the interior with only minor effects propagating to the boundaries.