Wisconsin Department of Natural Resources (WDNR) and Wisconsin Emergency Management (WEM) staff attended a meeting in Viroqua on Thursday, Jan. 11, to update local zoning and emergency management staff about the project to re-map the Kickapoo River Watershed floodplain. The reaches of the river to be re-mapped are from Ontario to Wauzeka.
WDNR staff in attendance included Christopher Olds, State Lead Floodplain Engineer, and Ben Sanborn, Floodplain Mapping Project Lead. WEM staff in attendance included Heather Thole, State Hazard Mitigation Officer, and Katie Sommers, Bureau Directorof Policy and Grants. Also in attendance were Vernon County Zoning Administrator Matt Albright, Vernon County Director of Emergency Management Brandon Larson, and Crawford County Director of Emergency Management Jim Hackett.
The maps are currently in a preliminary stage, with input being sought from local officials. A tentative timeline for final drafts being put out for public input is January of 2025.
The process being deployed to develop the new maps is ‘Risk MAP,’ with ‘MAP’ referring to ‘Mapping, Assessment and Planning.’ The process is intended to support community resilience by providing data, building partnerships and supporting long-term hazard mitigation planning.
“The Risk MAP process offers a way to understand the hard realities of hazards before they happen, and how to take actions now that help keep your community safe,” Sanborn said. “The process builds off previous FEMA map revision projects.”
Sanborn detailed that current effective mapping for the three counties included in the Risk MAP process are as follows:
• Crawford County, 2010 and 2015
• Richland County, 2016
• Vernon County, 2012
According to Sanborn, the project was kicked off in March of 2018 with learning about flood risk and mitigation needs, along with data collection and analysis to aid in determining the need for a new Risk MAP project. A kickoff meeting was held in January of 2022, where an overview of the Risk MAP process and National Flood Insurance Program (NFIP) information was provided.
At that meeting, a project timeline was laid out, along with a description of the areas to be studied and the hazard mitigation planning status.
H&H studies
At the core of the process are Hydrology and Hydraulics studies (H&H). Hydrology refers to the volume of water moving through the watershed, expressed in cubic-feet-per-second (cfs). This is how the amount of stormwater runoff is calculated. Hydraulics refers to the flood elevations or stream height that happens in a stormwater runoff situation.
“Hydrologic and hydraulic studies determine the potential depth of floodwaters, the width of the floodplain, and the amount of water that will be carried during flood events,” Olds explained. “The studies also take into consideration certain obstructions to water flow.”
Old said that his team had travelled to the area in 2022 to perform hydraulics surveys in-person at various bridges in the watershed. He said that the hydraulic study would use a combination of these kind of ‘detailed’ hydraulic studies, and ‘approximate’ hydraulic studies, using DOT plans for bridges and culverts, and aerial photos.
The hydrology study makes use of U.S. Geological Survey (USGS) stream gauge data where it is available (Ontario, LaFarge and Steuben), and also takes into account land cover and its capacity to infiltrate stormwater.
The study includes 14.7 miles of detailed hydraulic study, and 44.7 miles of approximate study in Crawford County. In Richland County (Viola area), 1.4 miles are detailed, and 5.7 miles are approximate. In Vernon County, 28.6 miles are detailed and 44.4 miles are approximate.
The end product of the study will be what is known as a ‘FIRMS’ map. This stands for ‘Flood Insurance Rate Maps.’ As WDNR staff present pointed out, “FIRMS are not predictions of where it will flood, and they don’t only show where it has flooded before. Rather, they provide a snapshot in time of flood risk.”
The steps in the process include a Flood Risk Review Meeting (completed), Preliminary FIRM released for input from county officials (current step). After this, a final draft of the maps will be released, and then there will be a meeting to obtain input from county officials, a public input meeting, and a 90-day appeal and comment period. After all appeals have been resolved, there will be a letter of final determination six-month adoption period, and then the new FIRMs will become effective.
The draft data will be viewable online at: https://msc.fema.gov/draft.
Concerns raised
The Independent-Scout raised two concerns with the new floodplain map development process. Those concerns were:
1. The rainfall definitions used in the H&H models are Atlas 14, which uses data up to 2012. According to NRCS State Conservation Engineer Steve Becker, the updated NOAA Atlas 14 precipitation depths were issued in 2014. The Kickapoo River floodplain model will either develop flood hydrographs using Atlas 14 precipitation depths, or they might use stream gauge stage-discharge data and USGS floodwater regression equations.
“NRCS commissioned UW-Madison to perform large storm extrapolations over a statistically shorter weather window (the last 15-18 years) to develop climate-adjusted precipitation estimate for the 2, 5, 10, 25, 50, 100, 200-year frequency, 24-hour duration storm events,” Becker explained. “The UW-Madison precipitation estimates were about six-tenths-of-an-inch (0.6) higher than the NOAA Atlas 14 precipitation depths for any given storm.”
Becker said that FEMA flood insurance studies need to stick with NOAA Atlas 14 depths because they are based on a statistically significant, rolling 30-year precipitation average.
According to Dr. Eric Booth, one of the UW-Madison scientists involved in the NRCS rainfall definitions study, it is looking likely that the new NOAA rainfall definitions (Atlas 15) will be released in 2026.
According to the NOAA Office of Water Protection (OWP) website, the following is true:
Historically, NOAA precipitation frequency estimates have been funded by states and other users, on a cost-reimbursable basis, forindividual subsets of the U.S. However, with the 2022 Bipartisan Infrastructure Law (BIL), OWP received first-ever direct Federalfunding to (1) update the NOAA Atlas 14 precipitation frequency standard while accounting for climate change, and (2) developprecipitation frequency estimates for the entire U.S. and its territories.
“These updated precipitation frequency estimates will be referred to as NOAA Atlas 15 and will be presented in two volumes. Volume 1 will account for temporal trends in historical observations, and Volume 2 will use future climate model projections to generate adjustment factors for Volume 1. To account for a changing climate, NOAA worked with the Federal Highway Administration (FHA) and the academic community to develop a new methodology for Atlas 15, which has undergone broad review by stakeholders and federal partners over the past year, leveraging state of the art research in extreme value theory and climate model outputs and projections. The Atlas 15 estimates will provide critical information to support the design of state and local infrastructure nationwide under a changing climate.
The FLOODS Act signed into law in December 2022 and known as Public Law No: 117-316, authorizes NOAA to establish a program, to be known as the NOAA Precipitation Frequency Atlas of the United States. This program would compile, estimate, analyze, and communicate the frequency of precipitation in the United States and update these precipitation frequency estimates no less than once every 10 years.”
2. The study will not take into account decommissioning of eight of the nine flood control dams in the West Fork Kickapoo Watershed, should that come to pass.
According to Becker, the FEMA floodplain mapping in West Fork Kickapoo River valleys never accounted for the existence of the nine flood control dams, likely because of their anticipated service life (50 years), or because the auxiliary spillways are activated at the 50-year-rain-event level for some dams, according to Uriah Monday, DNR State Dam Safety Engineer.
“This means that no adjustments are required in the base flood elevations in the tributary valleys or the Kickapoo River MainStem,” Becker explained.
Becker clarified that eight of the nine flood control dams in the West Fork Kickapoo Watershed (Ostrem, Hidden Valley, Seas Branch, Jacobsen, Clockmaker, Yttri-Primmer, Klinkner and Mlsna) are mapped in Special Flood Hazard Area - Zone A.
“This is just mapping symbology that grossly estimates the floodplain,” Becker explained. “They have no effect on the FEMA flood insurance study (FIS) floodplain. No detailed study (modeling or hydrology and hydraulics analysis) was performed in these areas, they were basically hand drawn based on topography.”
Becker explained that after decommissioning of the dams, WDNR would expect a ‘Letter of Map Revision’ (LOMR) that shows the dams removed from the map. The Zone A boundary would be adjusted on maps in the vicinity of the dams to reflect the flattening out of the flood hydrograph downstream.
Becker said that after this, the completed maps go to FEMA, and they confirm with WDNR. The county would then adopt the FEMA LOMR, with the new maps incorporated into the county ordinance.
The estimated engineering costs for the LOMR would be roughly an $8,000 FEMA fee plus $17,000 consultant fee, or $25,000 per dam ($200,000 total) for eight of the nine West Fork Kickapoo River dams.
NRCS proposes to rebuild the Jersey Valley Dam just below the location of the current breached structure. According to Becker, Jersey Valley Dam is a Special Flood Hazard Area - Zone AE.
The DNR would expect a Conditional Letter of Map Revision (CLOMR is a letter from FEMA commenting on whether a proposed project, if built as proposed, or proposed hydrology changes would meet minimum National Flood Insurance Program standards).
According to Becker, the CLOMAR/LOMAR would reflect an altered base flood elevation and floodway for a distance downstream to where the effect converges with the existing mapped floodplain (at intersection of Knapp Valley Road and Vernon County P). This revision would occur whether the dam is replaced or left breached. The estimated engineering costs would be roughly $100,000.
Building resilience
Heather Thole and Katie Sommers from Wisconsin Emergency Management (WEM) made a presentation to the group present at the January 11 meeting about products in addition to the updated maps that can help local officials make decisions about how to keep their residents safe.
These additional non-regulatory products include:
• Flood Risk Products: flood risk database
• Flood Risk Datasets: change since last FIRM (CSLF), and areas of mitigation interest (AOMI)
• Flood Risk GIS Data: water surface elevation grids, depth grids, percent annual chance of flooding and percent chance of flooding over a 30-year period.
“A hazard is not the same thing as risk,” Sommers explained. “Hazards are things that cause harm, for example floods or fires. Risk is the chance that a hazard will actually cause harm.”
Hazard mitigation
Sommers explained that FIRMS and the non-regulatory products help to identify flood risk in communities. She said that communities should use this information to identify mitigation actions with the goal of breaking the cycle of disaster, damage, reconstruction and repeated loss.
Mitigation grants
“Mitigation is any sustained action taken to eliminate or reduce long-term risk to human life and property from natural and technological hazards,” Thole explained. “For every dollar spent on flood mitigation, six dollars is saved in future damages, and that amount is seven dollars for riverine flooding.”
Thole explained that there is a new Congressionally mandated category of eligibility for FEMA mitigation grant funding called ‘Community Disaster Resilience Zones’ (CDRZ). This particular eligibility status is in place for five years, and increases federal cost share for some programs (BRIC and LPDM – see below) from 75 percent to 90 percent.
In Crawford County, the area included in the Reads, Tainter and parts of Knapp creek watersheds have been granted the CDRZ designation. In Vernon County, an area of the Middle Kickapoo River has been granted the designation.
Thole described four grant programs that FEMA offers for mitigation assistance. Those four are”
• Hazard Mitigation Grant Program (HMGP): this is a post-disaster program
• Building Resilient Infrastructure and Communities (BRIC): this is a pre-disaster program designed to build resilience
• Flood Mitigation Assistance (FMA): for repetitive loss and severe repetitive loss structures
• Congressionally Directed Spending (LDPM): this is an all hazards pre-disaster mitigation program led by a federal representative.
