30 Nov 2022

Numerical Analysis of Dike Effects on the Mississippi River Using a Two-Dimensional Adaptive Hydraulics Model (AdH)

Abstract: This report describes the hydraulic effects of dikes on water surface elevation (WSE) and velocities in the Mississippi River near Vicksburg, MS, from Interstate 20 to Highway 80 using a previously calibrated 2D Adaptive Hydraulics numerical model. Dike heights and their associated hydraulic roughness values were varied to quantify the overall effects of adjustments to dike fields. Steady flows characterized as low, medium, and high conditions were simulated. The WSE and velocity difference plots were generated to illustrate the hydraulic effects on the river under all scenarios discussed above. Overall, the dike adjustments had negligible impacts on WSEs and showed minimal effects on velocities on a system wide scale.

25 Jun 2020

PUBLICATION NOTICE: Hydraulic Analysis and Modeling of Navigation Conditions near the Mississippi River Bridges in Vicksburg, Mississippi

Abstract: The River and Estuarine Engineering Branch of the Coastal and Hydraulics Laboratory developed a two-dimensional numerical model of the Mississippi River near Vicksburg, MS, using Adaptive Hydraulics to investigate navigation conditions through the Interstate 20 and Old Highway 80 Bridges reach. A focus of the study was determining the Marshall Brown Dikes impact to velocities and navigation through the reach. Proposed dikes, focused on improving currents, were also tested to determine if they are a feasible option to improve navigability through the bridges. A second proposed alternative, a levee to protect the articulated concrete mattress (ACM) field, was also simulated to determine if flood damage to the ACM field could be successfully reduced without negatively impacting navigation. Velocity data from 2008 throughout the reach of concern were used for validation along with water surface elevation data from 2008, 2011, 2016, and 2018. The Marshall Brown Dikes were shown to have a localized impact on velocities near the dikes, but the changes to the velocity downstream near the bridge were negligible for all tested flow rates. Simulations of the proposed dikes did not result in an improvement to navigation conditions, but the proposed levee was successful in decreasing velocities and depths over the ACM field.