Funding: Federal Emergency Management Agency.

As 2D modeling becomes more prevalent, there is an interest in mapping Special Flood Hazard Areas and floodways using 2D modeling technology. While 2D steady state models are currently the most common, interest in unsteady 2D models are gaining ground.

Case studies of these efforts would document similarities and differences between steady-state traditional 1D methods and more robust 2D steady-state and unsteady methods. The purpose of this comparison is to determine the differences in the extent of the SFHA, and how well these modeling techniques can measure the flood-risk impacts of individual and cumulative development.

Currently state and local regulatory programs largely target limiting impacts of the loss of conveyance on areas upstream assuming 1D flow. We want to determine if the use of 2D models could better measure the development impacts.