Rock River at Janesville (Excerpt from SIR 2008-5235)
The Rock River runs south through the community of Janesville in central Rock County (appendix 8). The modeled inundated area of flooding is especially detailed because of the 1-m-resolution DEM data that were created from 2-ft topographic contours in the Janesville area. The accuracy of the USGS high-water marks was corroborated with nearby high-water marks surveyed during the flood by Janesville officials (appendix 8A). The city of Janesville has a high floodwall that was able to protect much of the downtown. Where the stream spilled over the floodwall on the upstream, north side of the city center, it was contained with sandbags and safely flowed down Main Street and inundated different areas than are shown in the modeled inundated area (appendix 8B). City officials provided the corrected inundated area on the basis of actual flood conditions in downtown Janesville.
Photo of high-water mark 2, August 13, 2008. Photo from USGS.
Appendix 8A. High-Water Mark Table (pdf) (excel) (shapefiles)
Appendix 8B. Flood-Peak Inundation Map (pdf) (shapefiles)
Appendix 8C. Flood-Depth Map (pdf) (grids)
Appendix 8D. Flood-Peak Water-Surface Profile (pdf)