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Hydrologic restoration being explored as flood control option
In Vernon County
Flooding in northern Wisconsin July 2016
SCENES LIKE THIS from the July 2016 flood in northern Wisconsin are all too familiar to the citizens of Southwest Wisconsin. Fueled by the state legislature making a $150,000 appropriation in 2019, northern Wisconsin communities in partnership with the Wisconsin Wetlands Association, have pursued wetland hydrologic restoration as an innovative flood control option.

VERNON COUNTY - The Vernon County Flood Mitigation Alliance (FMA) and Wisconsin Wetlands Association (WWA) are working together to pursue flood mitigation efforts in the Kickapoo River Valley. The two organizations hope to launch off modeling efforts for the watershed currently being undertaken by USDA Natural Resources Conservation Service (NRCS) and U.S. Environmental Protection Agency (EPA).

“What we would hope to accomplish would be to assist Vernon County with technical support and showcase techniques we have learned through other projects,” WWA’s Kyle Magyera explained. “In general, we want to collaborate in pursuing funding and overall, increase investment in risk assessment and demonstration projects.”

The collaboration is exploring funding that would allow them to use lessons learned from a pilot hydrologic restoration project in the Marengo River Watershed in Ashland County. That project was funded by the Wisconsin Legislature in 2019 as a means to explore natural flood mitigation methods in a flood prone watershed.

“Basically, a tremendous investment is currently being made at the federal level to help local agencies understand the flood prone watersheds they manage,” Magyera said. “What our two organizations are exploring is ways to leverage that investment to pursue putting projects on the ground that build on that investment.”

This week, the Wisconsin State Legislature is poised to vote on a bill that would simplify the permitting for such projects. Instead of having to pursue an individual permit, the bill would establish a general permit, administered by Wisconsin DNR. The bill was co-authored by Representative Loren Oldenburg and Senator Brad Pfaff.

July 2016 flooding

The Ashland project came about after catastrophic flooding in northern Wisconsin ravaged public infrastructure in July of 2016. Rainfall totals were 8–10 inches or more, and most of the rain fell within an eight-hour period.

Former Governor Scott Walker declared a State of Emergency in eight counties after severe flooding, widespread and continuing severe thunderstorms producing torrential rain, damaging winds, large hail and tornadoes forced the evacuation of persons, downed trees and power lines, and caused flash flooding damaging roads and bridges in the counties of Ashland, Bayfield, Burnett, Douglas, Iron, Price, Sawyer and Washburn amounting to a natural disaster. Three citizens lost their lives in that flood event.

In the aftermath of that flooding, the Wisconsin State Legislature passed Act 157 in 2019. That Act appropriated $150,000 to the Department of Natural Resources for the purpose of enabling Ashland County to test natural flood risk reduction practices in the county.

Design charette

The method that WWA used in the Ashland project was a design ‘charrette.’ The charrette approach convenes diverse resource experts to exchange ideas and develop innovative and collaborative solutions to a specific design problem. 

“We wanted a charrette that would emphasize cost-effective ways to address widespread flooding, erosion, and associated impacts,” Magyera explained. “Earlier work had found that erosion-induced wetland drainage and floodplain disconnection contributed to flooding and water quality problems in the Marengo River watershed.”

The Marengo River is a major tributary to the Bad River Watershed, which flows north and empties into Lake Superior. The river originates in the heart of the Chequamegon-Nicolet National Forest north of Clam Lake. Although the headwaters of the Marengo River are crystal clear and cold, the lower reaches appear muddy and account for much of the sediment entering the Bad River Watershed.

Magyera said the charrette goals were to:

• foster knowledge exchange between local resource managers and regional experts in fluvial geomorphology and hydrology

• demonstrate how an interdisciplinary approach can help identify the underlying drivers of flood hazards and degraded wetland and stream hydrology at any given site.

• review and discuss the information needed to determine the appropriate use of techniques to meet restoration goals.

• work through funding, budgeting, and evaluation considerations.

Magyera said the charrette began with a virtual workshop in early September, covering fundamental watershed hydrologic principles, geomorphic information specific to the Marengo watershed, and techniques commonly used to restore hydrology in various situations. 

The 27 participants included representatives from USDA Natural Resources Conservation Service, U.S. Fish & Wildlife Service, U.S. Geological Survey, Bad River Tribal Natural Resources Department, WDNR, UW-Extension, road and conservation departments from Ashland and Bayfield counties, Northland College, and Inter-fluve Inc. Together, they brought diverse expertise in geomorphology, hydrology, agronomy, soil science, engineering, road maintenance, and fish and wildlife management to the charrette.

Before heading out into the field, attendees joined WWA and presenters from various fields online to learn the basics of hydrologic restoration.

Field visits

After the virtual workshop, small cohorts from this group gathered for socially-distanced field visits to potential wetland restoration sites in Ashland County. These sites were on the shortlist of candidates for restoration under Act 157. The sites provided an applied hydrologic restoration planning experience for participants, and laid the groundwork to bring them all back during and after construction for further learning.

“We asked charrette participants to consider the historic context of the Marengo River watershed, current landscape conditions, and desired restoration outcomes,” Magyera explained. “They examined a range of low-tech practices for restoring floodplain and wetland functions and discussed how to cost-effectively restore the hydrologic processes needed at both the site and reach scales.”

Magyera said the field discussions proved fruitful, with all participants contributing needed perspectives and suggested solutions. He said they expect the construction of Act 157 natural flood management demonstration sites to start in spring 2022.