Camp Marmal Flood Study

The ERDC-CHL conducted the Camp Marmal Flood Study at the request of the Afghanistan District. Major flooding at the camp occurs from upland sources. The purpose of the study was to determine the effectiveness of flood mitigation alternatives. The AdH 2-D shallow water finite element model was implemented for the study. Boundary conditions for AdH were generated with HEC-HMS. The HEC model used local rainfall data to generate the routed run-off hydrograph from upstream watersheds. Existing conditions were simulated with the generated hydrographs to determine the potential flood characteristics of the facility and for the comparison of the alternatives. Additionally, a sensitivity analysis was conducted to determine the effect of variations in Mannings n and run-off return periods. The 20 year, 24 hour event was selected for simulation in the alternatives. The District provided three alternatives for evaluation in the model. Alternative 1 provided minimum protection. Alternative 2 showed increased protection, but there were several issues of concern that made it less ideal. Alternative 3 potentially provided the most flood mitigation. However, prior to construction of any alternative it is recommended that the final design be simulated in the AdH model.