Reducing Flood Risk in the South Shore Watersheds of Gichigami
Photo credit: Airfox Photography LLC
Project Overview
SRWA, the Wisconsin Wetlands Association, Northwest Wisconsin Regional Planning Commission and other partners are engaged in an ambitious four-year initiative focused on identifying regional flooding risks, specifically how loss of headwater wetlands and floodplain connectivity contributes to flood risk in four South Shore Lake Superior watersheds (Nemadgi River, White River, Fish Creek, and Montreal River). The project is funded by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Resilience Regional Challenge grant program, building on completed flood risk assessment work on the Marengo River watershed. A major goal of the project is identification of flooding-vulnerable locations in the four watersheds, with emphasis on natural flood management (NFM). NFM restoration strategies emphasize use of existing natural water retention infrastructure like stream floodplains, wetlands, and runoff-slowing shrubs and trees, to reduce flooding in flood-vulnerable sites at much lower cost and greater efficacy than human-made flood control infrastructure.
(Climate change-accelerated seasonal and catastrophic flooding and sediment load to Lake Superior)
This flood resilience assessment project will generate information to help communities understand the drivers of seasonal and storm event floods and the erosion, sedimentation, and debris issues result. New data and mapping will lead to identification and prioritization of restoration sites, project planning, and funding procurement for NFM and engineered infrastructure flood management projects. The ultimate goals of this initiative are improved community flood resilience, reduced road infrastructure maintenance expense, and protection, and restoration of regional ecological values like animal and plant habitat, water quality, and the perpetuation of access to treaty-guaranteed resources and recreational opportunities.
This project addresses multiple watersheds along the South Shore of Gichigami, including Waabishkaa-ziibi (White River), Agaawaa-
zaasijiwan-ziibi (Montreal River), Mitaabikitigweyaa-ziibiwishenh (Fish Creek), and Namanjii-ziibi (Nemadji River). This work builds upon a pilot assessment project in the Marengo River Watershed.
What will happen in and around the Chequamegon Bay?
The project actions in the Mitaabikitigweyaa-ziibiwishenh (Fish Creek) and Waabishkaa-ziibi (White River) Watersheds are designed to help communities prepare for and withstand flooding and storm events by identifying where to focus flood risk reduction projects.
1. Comprehensive culvert inventory to understand the locations and urgency of
infrastructure risks.
2. Community conversations to better understand flood vulnerabilities and how
the movement of nibi (water) near infrastructure has changed.
3. Assessment of slow the flow potential to help communities identify opportunities that reconnect and restore wetlands and floodplains that have been altered, improving their ability to slow the flow.
4. Technical support to help communities use the final flood resilience assessment data and maps for each watershed.
What places in the mapped area below are already known to be at risk from flooding? Are there places along roadways where you notice bigger or flashier flows, sediment and debris buildup, or wetlands drying up? What information is needed to help communities prepare for and respond to floods? Superior Rivers Watershed Association is helping this project by gathering information from tribal and local governments and residents in the Ceded Territories near Chequamegon Bay. To share observations or discuss this project, contact Alex Faber (alex@superiorrivers.org) and Emma Holtan (emma@superiorrivers.org).
Predicting flood vulnerability by identification of Fluvial Erosion Hazards
By 2023, basin restoration partners had completed a flood risk study on the Marengo River watershed, the southern Lake Superior basin’s most erosion-impaired watershed. A set of landscape characteristics that were either results of erosion or considered risk factors for erosion were identified and referred to as fluvial erosion hazards (FEHs). Examples of FEHs are: steep channel gradients, sandy streambeds, steep stream valley slopes, erodible or low-permeability soils, mass-loss features like collapsing streambanks, gullies, and incised stream channels, repetitive road culvert washout sites, and more.
Related to this work, road culvert inventories carried out by partner agencies Trout Unlimited and the US Forest Service are updating our knowledge of washout-prone and eroding culverts at road/stream crossings across the basin. Guided by local watershed management plans-state and federally-recognized documents known as Nine Key-Element Plans-further identify and prioritize flooding and erosion issues {and much more), and help communities identify funding opportunities for restoration projects. A nine key-element plan has been in place for the Marengo River watershed for 13 years, and plans are in development for the Fish Creek and White River watersheds. This important work is funded through the US-FWS Headwaters to Coast program, Great Lakes Restoration Initiative, FEMA Act 157 flood mitigation funding, and other initiatives. . Each watershed is within the territory ceded in the Treaty of 1842.
- Outputs: Catchment-level flood risk assessment and restoration site identification, prioritization, and natural flood management application method choice are informed by a combination flood risk score and presence of existing functional natural infrastructure (wetlands and PRWs) (reference example).
- Goal: NFM restoration strategies will be applied to four additional HUC-10 watersheds in the basin, closely coordinating efforts between agencies, NGOs, and communities
- Concurrent ongoing and planned projects:
- Steam bank restoration-Burke Center for Ecological Research
- Pilot floodplain reconnection projects
- Road/stream crossing inventories and upgrades-TU, US-FS, and local government