Friends of Cherokee Marsh comments on developing a long-term plan for a portion of the Cherokee-Yahara River Estuary

Here are the comments submitted by the Friends of Cherokee Marsh in response to the public meetings on developing a long-term plan for a portion of the Cherokee-Yahara River Estuary.

The Friends of Cherokee Marsh appreciate the interest taken by Dane County, UW Civil & Environmental Engineering, the DNR, City of Madison, and others in the health of the upper Yahara River at Cherokee Marsh.

We will welcome projects that help stem continued loss of shoreline wetlands at Cherokee Marsh and provide other benefits.

Steering committee

We are disappointed that the Friends of Cherokee Marsh were not asked to participate in meetings of the Cherokee Steering Committee as the grant specifies. We request to be included as participants in all future communications and meetings of this committee.

We strongly recommend that any proposal put forth by the steering committee includes analysis from wetland ecologists that have experience with the upper Yahara or similar peat wetland ecosystems. We can’t support proposals that don’t include input from these sources.

Alternative concepts

The grant states that the team will explore several concepts for restoring Cherokee before proceeding to analysis in Phase 2. Yet the peninsulas concept is the only one apparently under consideration. We believe that considering a range of options will help ensure that the selected plan will be effective, affordable, and supported by the public.

We have substantial reservations about the idea of dedicating the upper Yahara and Cherokee Lake as a catch basin for nutrient-rich sediment. We support the work by the county and others to address conditions that are producing sediment in the river.

The grant states that the FBI structures were successful in stopping shoreline erosion. Yet this project has been abandoned, leaving the structures to work loose and float away. We are concerned that future projects may suffer the same lack of maintenance over time.

From our observations as well as the data presented at the public meetings, the beds of American lotus and other submergent and emergent plants established in the last 15 years have been effective at calming the water, protecting the shorelines, capturing sediment, and providing wildlife habitat. Before planning a major construction project with similar goals, we recommend continued and expanded documenting of shoreline erosion or buildup, vegetation, sediment capture, and other indicators of ecological health in different seasons and rainfall patterns. This information will help to better understand what areas are in need of attention and what strategies might be effective.

We support continued carp harvests as needed.

Peninsulas concept

These are our concerns about the peninsulas concept as presented.

We’ve seen no evidence that the peninsulas concept has been examined by wetland ecologists who can address concerns such as those we present below.

The shoreline wetlands in the Cherokee Marsh flowage (the area of the Yahara upstream from Lake Mendota and flooded by the Tenney Park dam) are fragile because they are floating, not rooted in the river bed, and only loosely attached to adjacent vegetation. Rapidly changing water levels due to storm events cause these wetlands to rise and fall as if on hinges. The force of repeated motions of this type results in the wetlands breaking off and floating downstream where they fall apart and are lost forever.

If peninsulas are constructed adjacent to floating wetlands, during major storm events, water will seek a route around the inland edges of the structures, eroding those wetlands and converting the peninsulas into islands.

If peninsulas constrict the river’s flow, during major storm events, water will back up behind the structures, putting upstream shoreline wetlands at greater risk of breaking off. We’ve seen this effect caused by the constriction at the HWY 113 bridges downstream.

Any further research into large construction projects should include discussion of the feasibility of hauling materials on the shallow river.

It’s hard to evaluate a major proposal such as the peninsulas concept without some idea, however tentative, of the cost to build and maintain the structures. Thus it’s impossible to estimate if the benefits would justify the expense and inevitable negative consequences, some of which are as yet unknown, or if the marsh and downstream lakes would see more benefit from other efforts, even if that means focusing on different approaches and other parts of the watershed.

Future activities

We request that the materials presented at the meetings be posted online.

We support performing a bathymetric survey and preparing project base maps displaying river bottom, shoreline conditions, vegetation, structures, roads and trails as proposed in Phase 2 of the grant.

We don’t support moving ahead with the peninsulas concept until it has been vetted by wetland ecologists.

We look forward to being included in future steering committee meetings and other activities and would appreciate confirmation of this by the steering committee.

Thank you for the opportunity to comment.

Jan Axelson

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