Rock River Flood Inundation Mapping Project
With a total drainage area of 3,474 square miles, the Rock River has flooded extensively numerous times over the years. Many of the flooding events occurred between 1982 and 2010. In the past 25 years, flooding on the Rock River has resulted in eight Federal Disaster Declarations. Historic flooding in 2008 caused the Rock River to hit "major" flood stage three separate times in that year alone. The Rock River Flood Inundation Mapping project was implemented through a partnership among the Wisconsin Department of Natural Resources, Wisconsin Emergency Management, USGS, National Weather Service, and USACE. By combining USGS stream gage data with hydraulic modeling and digital elevation data, a library of flood boundaries can be assembled for a series of incremental flood stages and overlaid on digital orthophotographs of pertinent areas to visualize areas of potential flooding. The project covers reaches of the Rock River located in Jefferson, Dodge, and Rock Counties, WI, encompassing approximately 31.8 river miles. The flood inundation maps are critical to flood emergency management planning and implementation; conveying flood risk to the public as the National Weather Service forecasts can be mapped and visualized for areas expected to flood well in advance of occurrence; and many other flood risk reduction and floodplain management initiatives and actions. The maps will be published on both the USGS and NWS websites.
Links to inundation maps at:
Columbia County Floodplain Structure Inventory and Flood Reduction Strategy
Numerous flooding events have occurred in Columbia County, Wisconsin. Since 1982, the County has experienced 36 flooding events, including five that resulted in the County being included in Federal Disaster Declarations. In 2010, the Wisconsin River at Portage set a new record crest of 20.66 feet on September 28, or 3.66 feet over flood stage. This project completed a structure inventory of properties located along and near the Wisconsin River in Columbia County that are prone to flooding. There are 2,962 parcels located in the 100-year floodplain. Of the total parcels, 1,198 have at least one improvement on them (residential, commercial, or farm related). The information will allow the county to improve protective measures and evacuation options during flooding. The project will also assist both officials and property owners in high-risk areas to identify feasible, cost-effective mitigation measures, thus lowering future response, repair, and recovery costs paid by victims, their families, taxpayers, and FEMA. The project was accomplished through the effort of the USACE with input from other stakeholders including Wisconsin Emergency Management, Wisconsin Department of Natural Resources, Columbia County, and local officials.