JACKSON COUNTY, WI - Following a devastating flood in 1993, the city of Black River Falls, located in Jackson County, Wisconsin, incorporated a concept known as “freeboard” in reconstructing their levee. Freeboard is a factor of safety usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, bridge openings, and the hydrological effect of urbanization of the watershed.
Freeboard is not required by NFIP standards, but communities are encouraged to adopt at least a 1-foot freeboard to account for the 1-foot rise built into the concept of designating a floodway and the encroachment requirements where floodways have not been designated. Freeboard results in significantly lower flood insurance rates due to lower flood risk.
With a flood stage of 47 feet, the levee definitely passed the test in September 2010 when water from the Black River rose 20 feet in a 16-hour period, cresting at 61.4 feet (0.2 feet higher than its historical crest of 61.2 feet on June 20, 1993). Referred to as the “Father’s Day Flood” by residents in Black River Falls, the Great Midwest Flood of 1993 wreaked havoc, caused widespread damage, and was the most costly and devastating flood to ravage the United States in modern history. Levees were breached; farmland, town, and transportation routes were destroyed; thousands of people were forced to abandon their homes; and 47 people died as a direct result of the flood. In Black River Falls, more than 80 homes located in an area referred to as “The Grove” were affected when an earthen levee was breached. Valued between $80,000 and $90,000, the homes sustained an average of $30,000 each in damages.
Partly funded by the Federal Emergency Management Agency (FEMA) and the Economic Development Administration (EDA, a U.S. Department of Commerce agency that provides grants to economically distressed communities), the city took on a mitigation project to rebuild the levee, which had originally been constructed in the 1930s, adding a 3-foot freeboard.
At a cost of approximately $5,000,000, improvements on the 3,565-linear foot levee began in January 1994 and were completed in January 1997. Black River Falls received funds totaling $2,014,000 from FEMA to execute a buyout project and to reconstruct the levee along the residential district. EDA provided nearly $3,000,000 to reconstruct the portion of the levee along the commercial district.
On September 23, 2010, the city ordered the evacuation of the area of the Grove that is south of Fillmore Street up to 3rd Street. Fearing a repeat of the 1993 flood event, residents in “The Grove” were ordered to evacuate as rising water challenged the levee’s fortitude. Black River received nearly 7 inches of rain over a 2-day period. Residents returned to their homes the next day to find them unscathed because the levee held.