One year later, Dane County is still feeling the effects of a record-setting rainstorm that dropped more than a foot of water in some areas and resulted in the death of one Madison resident, over $154 million in damage and historically high lake levels.
Damage caused by the Aug. 20, 2018, storm across the western portion of Dane County and the west side of Madison is still visible as are the effects of record groundwater levels — a challenge facing Dane County today as a result of last year’s and current rainfall levels, Executive Joe Parisi said.
“You can see that as you drive throughout the county, and you see areas that were cropland that are underwater now,” Parisi said at a press conference Monday. “If we get a heavy rain event, the ground is already saturated so there would certainly be flooding.”
In 2018, Dane County’s rainfall was 18 inches above normal. To date in 2019, the area has received eight inches of rain above normal rates, Parisi said. High groundwater tables have caused millions of dollars in agricultural production losses, he said.
Nearly one in 10 acres of Dane County cropland were not planted this year due to flooded fields, Parisi said. In past years, 1% to 2% of farm lands were left unplanted. In addition to flooded farmland, the higher water tables are resulting in more basement flooding in areas where this typically has not been a problem.
Approximately 60% of damage claims filed with the Federal Emergency Management Agency came from properties that experienced flooding from Black Earth Creek — in Mazomanie, Black Earth and Cross Plains. Madison’s west side, Middleton and Shorewood were also hit hard due to rapid stormwater runoff.
Only 3% of the total FEMA claims were a result of flooding from the Yahara River watershed. To date, FEMA has awarded $3.8 million in claims to 917 Dane County households.
Dane County is limited in terms of what it can do about the increased groundwater levels, which are a function of rainfall.
“It will be an ongoing effort for years to come to make certain we can to keep people safe and to do what we can to address the root causes of the pieces of it we can control,” Parisi said. “We can’t control the weather. We can’t stop it from raining 15 inches in one event like it did last year, but we’re doing everything we can to make sure we can respond as best as possible.”
Flood readiness, mitigation strategies
In response to last summer’s flooding, Parisi included $18 million in the 2019 budget for flood-related expenses. These included sandbagging machines that can be taken to communities, inflatable barriers, an airboat for rescues, weed cutters and a lake debris barge.
“We believe we’re even better prepared to respond from a first responder perspective because of the enhancements,” Parisi said. “We’ve been through the drill a year ago.”
Dane County purchased 160 acres next to the Pheasant Branch Conservancy to restore as a way to reduce runoff volume and nutrients delivered downstream to the Yahara Lakes. Additionally, the county purchased two properties next to Babcock County Park with over 600 feet of shoreline to better manage water flow through the Lower Yahara River.
Dane County Emergency Management and Dane County Planning and Development are currently evaluating the potential flooding risk for homes that do not fall within FEMA’s floodplain designation but could be susceptible to water damage as a result of climate change rain events.
Parisi announced he would fund a public education campaign in the 2020 budget to inform residents how to protect their properties, even if they’re not in an identified floodplain.
“This is going to be a long term change and like many parts of the nation, we’re going to be dealing with different types of weather patterns,” Parisi said.
This fall, Dane county will begin a multi-year, five-phase plan to remove sediment from the bottom of the Yahara River and areas lakes to improve water flow out of lakes after heavy rains. The first phase will address the area between Lakes Monona and Waubesa, is expected to remove 40,000 cubic yards of sediment and will cost about $3 million.
Sediment builds up over decades but has not been an issue in the past, Parisi said.
“Our system was fine for the way our weather used to be, Parisi said. “What we have to do now is adapt to a changing climate and this is part of it.”
Dane County has also implemented a continuous cover program that converts traditional row crops to permanent vegetation, removed 700 loads of aquatic plans from the Yahara River to improve flow, ensured Tenney Dam is strong and is providing $1 million to restore streambanks.