Results: Analysis
One-Dimensional vs. Two Dimensional Comparison
The maximum extent of flooding was very similar between our one-dimensional and two-dimensional models. We believe that because the river segment we modeled was relatively straight and short, the differences between the two models are less pronunced. In General, the two-dimensional model boundary extended slightly further outward from the river segment. We consider the two-dimensional model to be the more accurate one because the unsteady flow analysis better depicts the unsteady nature of a flood event, and the 2D mesh gives an enhanced representation of the land surface for inundated areas.
Two Dimensional vs. Flood Risk Areas Comparison
Tenney Park
When comparing our two-dimensional flood model to a map of flood risk areas released by the City of Madison during the 2018 floods, you can quickly see that our model matches the potential flood map in Tenney Park and the grassy area kitty-corner to the east. The model's flood boundaries also dip into all of the flood risk areas along the river segment. However, the model's flood extents don't seem to make sense with the flood risk areas as a whole. This is because our model accounts for overland flooding from this river segment, but flooding on the isthmus could also be caused by a rise in lake levels in the form of overland flooding or storm sewer backup. With three separate avenues for the water to take when flooding the isthmus, our model alone is not adequate to evaluate flood events here. Lake levels, storm sewer inlet elevations, and more detailed elevation data of the isthmus as a whole would need to be added to this model to help understand flood events here.