Flooding in the Kickapoo River drainage basin and southwestern Wisconsin

Southwestern Wisconsin: Flooding Due to Natural and Human-Created Vulnerabilities

The areas of Southwestern Wisconsin located near the Kickapoo River saw record flood totals in June of 2008. The immediate cause of the flood was a series of storms in which seven southern counties received more than a foot of rainfall during the first half of the month. Precipitation records were set 114 times in Wisconsin cities and towns, day after consecutive day. Unlike the 2007 floods, the 2008 floods were due to unusually consistent and seemingly never-ending rainfall amounts. In two of the most severely impacted cities, the town of Ontario received more the 6 inches on June 8th, and the town of Baraboo received more than 17 inches of rainfall during the month ("Floods in Wisconsin," the Wisconsin Historical Society, 2009).

Dams, rivers, and streams, and nearly every residential and commercial area was affected: "Lake Delton, located in the Wisconsin Dells in south central Wisconsin, breached its dam and emptied into the nearby Wisconsin River on the 9th, sweeping away three homes and part of a highway. Thirty-one Wisconsin counties were declared disaster areas, more than 40,000 homes and 5,000 businesses were damaged; state officials estimated the total damage at more than $1.2 billion" ("Floods in Wisconsin," the Wisconsin Historical Society, 2009). The causes of the 2008 flooding were attributed by the Wisconsin Department of Military affairs to the 2007 winter's record-breaking snowfalls which never had time to be absorbed by the ground. "Following the summer's heavy rains, water levels in some wells in southern Wisconsin were nearly 10 feet above their historic highs" ("Effects of climate change in Wisconsin: Flooding in the south, drought in the north," Wisconsin Geologic History and Natural Survey, 2009). The same region of the state had already been hard-hit in 2007: that year, heavy thunderstorms dumped 10 inches of rain from Iowa to Wisconsin. "Significant flash flooding developed during the overnight hours in drainage areas. Mud and rock slides were also common given the steep terrain in that area" ("Flash Flooding along Iowa - Wisconsin border," CRH, 2007).

However, an alternative analysis has been offered for the severity of flooding, beyond that of the impact of the heavy rain. True, the rainfall activity was catastrophically intense during June. But according to the Wisconsin Geologic History and Natural Survey, even earlier floodwaters had remained high for months. Southwest Wisconsin had undergone notable geological changes that left the underground water table virtually level. "When the rising water table reaches the land surface, groundwater flooding occurs," as before floodwaters can dissipate, the underground layer of rock that holds water must lower ("Effects of climate change in Wisconsin: Flooding in the south, drought in the north," Wisconsin Geologic History and Natural Survey, 2009). "The amount of rise in the water table depends on many factors, including the amount of precipitation, soil type, plant type, temperature, and porosity of the underlying aquifer" ("Effects of climate change in Wisconsin: Flooding in the south, drought in the north," Wisconsin Geologic History and Natural Survey, 2009). The combination of more severe storms due to climate change combined with higher water table, river, and stream levels, also due to climate change, means that groundwater flooding is likely to become more common than in the past, in an area that has always had a great deal of flooding.

Historically, floods have always been part of Wisconsin life. French-Canadian residents of Prairie du Chien complained as early as 1785 of the flooding. Another historic flood occurred on September 11, 1884 when a 27-foot flood carried away houses and all the bridges in Eau Claire. At the beginning of the 20th century, heavy rains filled the upstream tributaries to the Black River and caused two dams above Black River Falls to give way and allow the waters to destroy 85% of the business district ("Floods in Wisconsin," the Wisconsin Historical Society, 2009). Large dams have thus proved ineffective historically yet smaller dams, such as check dams are only effective in narrow areas, such as channels that drain areas smaller than 10 acres. Check dams also require additional maintenance for high-velocity flows ("Check dams," CASH, 2009).

Kickapoo Valley was hard-hit by flooding in 1951: "When more than 8 inches of rain fell during the last week of July, floodwaters tore through Crawford, Vernon, and Richland counties as the Kickapoo emptied into the Wisconsin. Gays Mills was submerged five feet deep in water, buildings floated away at Boaz, and all six members of a family near Viroqua drowned when their farmhouse was swept downstream" ("Floods in Wisconsin," the Wisconsin Historical Society, 2009). As is illustrated by this anecdote, flooding is almost always devastating to the residents of an area -- many Wisconsin residents lost everything from the flooding that occurred. Ecologically, from a holistic perspective, flooding can have some benefits, by returning nutrients to the soil, opening up the land to new habitation by a variety of species and replenishing wetlands. Also from a long-term perspective, wetlands can receive runoff from higher areas affected by heavy rains.

Flooding also has historically worked to counteract the severity of droughts. However, one interesting component of Wisconsin's struggles is that while some areas of the state have suffered terrible floods, others have been afflicted by a lack of precipitation ("Effects of climate change in Wisconsin: Flooding in the south, drought in the north," Wisconsin Geologic History and Natural Survey, 2009). Current geographical and climate changes have been 'ill winds' that have brought few residents any 'good.'

It has been possible in some areas of the state to mitigate the effects of flooding. Coon County has been one notable exception to the intensifying patterns of flooding in the area. During the 1930s, agricultural practices were modified to mitigate flooding: the newly created Civilian Conservation Corps (CCC) increased the degree of land slope to divide land tracts of farmers. Relatively flat bottomland and land sloping from 2-20% were made into cropland or pasture. Slopes from 8% to20% were put into contour strips to protect the pasture. Then, "the 20-30% land was fenced for pasture by the CCC crews, and the steeper land was used for woods. These same guidelines were used on ridges to separate land use" ("Coon," Vernon County, 2009).