Wisconsin Geospatial News

Improved flood hazard mapping on the way

That great sigh of relief you may have heard lately is due to the promise of significant upgrades to flood hazard maps across the state. Fueled by a huge increase in federal funds allocated to the Federal Emergency Management Agency (FEMA) for map modernization, our state stands to benefit significantly over the next decade.
In general, more heavily populated counties in the southern part of the state will be the first to be mapped, according to Alan Lulloff of the Wisconsin Department of Natural Resources (DNR). Lulloff has been working with FEMA to coordinate the mapping in Wisconsin. DNR has received approval from FEMA to manage the flood map modernization effort in Wisconsin. This arrangement would steer the work to contractors in the state, rather than having FEMA award contracts to national firms.
For many years the maps used to determine the need for flood insurance have been known to be of low accuracy. Modernization will result in a major improvement.

Determining priority areas for funding
The rationale for concentrating early work in the southern counties is based on two factors. First, most of these counties already have detailed topographic information, in some cases adequate to develop accurate two-foot contours. That level of detail and accuracy is important to improving the delineation of areas likely to flood and substantially reduces the cost of doing the hazard analysis.
Second, these counties have the highest density of structures at risk, and have more impervious surface area, which increases runoff from major precipitation events.
Projects will begin in the following counties first: Brown, Ozaukee, Waukesha, Milwaukee, Rock, Dane, and Washington.

Major funds involved
DNR has received a first installment of $800,000 in FEMA funds to begin the work this fiscal year. At the national level, FEMA’s annual budget for flood map modernization was increased last year from $50 million to $250 million. Ultimately, Wisconsin may receive $10-20 million under the program. Due to the amount of aerial photography and topographic mapping that has been developed in Wisconsin primarily through the Wisconsin Land Information Program, DNR will be able to increase the number of streams that have published flood elevations in the State.
Improved mapping of flood hazard areas will help determine which property owners need flood insurance to protect their investment, and which do not. In addition, better information will assist in developing flood mitigation strategies that are designed to minimize risk. Wisconsin suffered $1.5 billion in flood-related damages over the last 14 years. That ranks tenth among states.

Web resources available
To learn more about the modernization of flood mapping, you can consult several web-based resources:
DNR’s page on Flood map modernization
Association of State Floodplain Managers
Progress reports from FEMA