Marengo Action Plan Progress Update

Back in 2013, SRWA (then known as the Bad River Watershed Association) developed and obtained EPA/WDNR certification of an EPA-approved 9-key Element Watershed Management Plan for the Marengo River Watershed. It was the first of its kind in Wisconsin. In the ensuing years, the plan provided important guidance for local government agencies and watershed residents planning beneficial activities such as culvert replacement, agricultural waste management, runoff control, invasive plant species control, and much more. The existence of the management plan also added credibility to numerous grant proposals for water quality and habitat related projects within the watershed. To retain EPA certifications, 9-Key Element Plans must be revised every 10 years and submitted for WDNR and EPA review. With the Marengo Plan’s revision deadline coming up in 2023, SRWA obtained an $18,000 grant from the Wisconsin Coastal Management Program to complete the revision process during 2022. The purpose of revising these plans is that management needs and priorities can change over time, projects are completed and priorities gradually shift. In the case of the Marengo Watershed, the catastrophic flood events of 2016 and 2018 significantly changed a number of restoration project priorities, and exciting new data was coming from FEMA-funded flood risk and natural flood management studies being conducted through a partnership of Ashland County, the Wisconsin Wetlands Association, the Bad River Tribe, and several other resource agencies. Also at this time, WDNR released a comprehensive “Slow the Flow” white paper addressing the scope and management solutions for excessive runoff and erosion that have plagued the southern Lake Superior basin for the last 100 years. The timing of the Plan’s revision couldn’t have been better for incorporation of all of these timely and important new data.

After 14 months of editorial work and monthly inter-agency review team meetings, SRWA completed the revision work and submitted the draft Plan revision to WDNR and EPA in September. Now we must wait three to six months for the review process to be completed. Barring additional revision work, the plan should be re-certified sometime in early 2023, starting its next decade of service to watershed stakeholders.

SRWA staff and the review team did a great job with this very large project, and we can’t express enough gratitude to everyone who helped with this process. Once again, local and regional collaboration for the benefit of the Big Lake and its watersheds has been extraordinary!  

Identifying and Assessing Flood Risk in the Watershed

The Marengo River Watershed is particularly at risk for flooding because of historic reduction of runoff-slowing forest cover, steep stream gradients, clay soils that shed runoff, and presence of manmade structures such as road and field ditching networks. A large number of tributaries flow into the Marengo River from areas that have concentrated farming activities, open land, clay soils, and an extensive road network. All of these factors result in rapid movement of high volumes of water through the watershed during heavy rain events and spring thaw.

In 2019, Ashland County, the Wisconsin Wetlands Association and several other partner agencies launched a project called Rebuilding Natural Infrastructure in Ashland County, aimed at reducing damage to roads, culverts, and bridges by prioritizing where restoring wetlands and their connection to stream systems can reestablish the landscape’s capacity to store and manage water. The project is funded by the Federal Emergency Management Agency (FEMA) and partner matching contributions.

The project study has since gathered extensive data on erosion hazards in the Marengo River Watershed, and evaluated opportunities to restore stream, floodplain, and wetland conditions upstream of vulnerable locations such as road/stream crossings.

One of the primary goals of the project was to better assess flood risk by identifying key factors causing floods, and where flood risk is highest by:

• Identifying vulnerable public infrastructure and upstream erosion hazards
• Identifying and prioritizing upper watershed wetland and floodplain restoration opportunities
• Updating Ashland County’s Hazard Mitigation Plan to include wetland and floodplain restoration strategies
• Using the inventory of vulnerable infrastructure to prioritize and plan flood resilience into future transportation projects

Some of the more important risk factors that the project identified are:

• Steep stream valley sides
• Steep stream channel gradient
• Lack of upland forest cover
• Flood and erosion enhancing soil associations
• Road and agricultural ditch systems
• Degraded natural stream floodplain flood buffering

These factors can be formulated into a risk score for a given tributary watershed or section of highway for example, and give local governments a heads-up on how to prevent future flooding through building increased flood resilience into infrastructure such as culverts, undertaking wetland restoration projects, closing unused ditch systems, and much more. By improving stakeholder knowledge of flood risk and opportunities to prevent them, this project allows:

• Focus of restoration activities and resources on most flood-prone areas
• Improved flood preparedness for residents and emergency response agencies
• More responsible development planning that takes into account flood-prone areas and natural flood control potential of the landscape

Much of this exciting new data coming from this project and others has been incorporated into the recently-completed 10-year revision of the Marengo River Watershed Management Plan. When the new Plan is published in early 2023, readers will be able to access this information in greater detail and be guided to local responsible agencies, funding sources, and how best apply it to their communities.

Recent Workshops and Activities

The growing interest in regional flood prevention has resulted in organization of several informational workshops aimed at culvert washout prevention and stream restoration in our area. Earlier this summer, The Wisconsin Wetlands Association and Ashland County hosted culvert workshops for local highway departments at the Ashland County Highway Dept. shop, and at the Morse Town Hall. Trout Unlimited also hosted a road/stream crossing design workshop in early October at the Northern Great Lakes Visitor Center. These events focused on the damage caused by recent flooding events, results of new studies of flood risk and natural flood control, and future opportunities for project funding and agency collaboration. SRWA presented an update on the Marengo River Watershed Management Plan revision at the Trout Unlimited event, drawing a lot of great questions from participants.

Other News and Announcements

Two nests hatched on the Marengo River turtle site. All eggs hatched on Nest #1.  Nest#2 had four eggs that didn’t hatch and eight that did.