Tonight, the Lake Level Task Force held a public hearing. Several community members spoke in favor of and against three of the options in the technical report: 1.) Lower Lake Mendota, 2.) Dredging, and 3.) Rerouting and Pumping. We heard passionate arguments in favor and against each of these options. In addition, we heard support of exploring more infiltration options. After reading all of the reports, the presentations of the scientists, and public comments, I have come to some long, medium, and short term goals that I would like to see come out of the recommendations of the Task Force. I have written them here in order to get feedback from those of you living on Lake Monona, the everyday-experts; those of you who spend a bit of time every day on the lake, who monitor lake levels throughout the season, and who have too much experience with sandbags.
First, a few quick resources for background informaiton:
The Yahara Chain of Lakes - Lake Levels Task Force has met four times, for several hours, and each of us has read many reports of work done both for this iteration of the lake discussion, as well as historical documents. My approach for supporting resilient lakes that can respond to increasing rain events, in severity and frequency is prevention at the upstream sources. However, many of those options will take time. So, they must be combined with actions that can be taken as soon as possible. The suggestions that I offer, are supported by the experts on the committee, those that testified, and the models that were run during the study—they are science-based solutions. They are listed in, what I believe to be, chronological order of ability to see impact.
Additionally, if there are possibilities in jointly addressing flooding and phosphorus in our lakes, then extra attention should be paid to those options.
Short-term (1–2 years) — Increase Flow
There is some thought that if the permitting began very soon, we could see some of the biggest bottlenecks in the system of lakes improved yet this summer. We must take action that will move water water out of the system before any other scenario can be considered. Pages 12–15 of the technical report show some of those choke points in the system. Figure 8 (included below) is an example. You can see the uneven bottom of the Yahara River. Dredging would allow for the water to continue to move more downhill rather than facing the friction of an uneven surface.
Adjust Mangement Manual to Manage Lake Levels at Seasonal Minimums
With input from County Staff, there could be an adjustment to the management manual to manage the lakes at a seasonal minimum until the impact of the actions taken can be evaluated. The trouble with this is, even if the manual is changed, getting the lakes to the seasonal minimum could prove problematic given how much snow we have on the ground, and will depend on the rainfall we see this spring and summer.
Medium-term (3–5 years) — Continue to Increase Flow & Systemic Changes
Infiltration has long and medium-range goals. The idea of infiltration is that we create more opportunities for rainwater to soak into the ground like a sponge. We can do this by creating environments that are softer, and including plants that absorb more water. Nature provides these in the form of wetlands, an incredibly valuable resource in flood resistance. In the shorter-term we can be restoring wetlands. When this was first proposed, I thought for sure this would be a multi-decade action. However, a community member and staff at The Nature Conservancy informed me that it is actually a much shorter timeframe than that. In a couple of years a wetland can be up and functioning to promote infiltration.
What I would like to see is an analysis of how much we need to increase infiltration to make the difference we really need to see for the impact of our lakes.
Additional benefits of increasing infiltration is that it reduces sediment accumulation, which reduces the amount of dredging maintenance necessary. It could also promote a reduction in phosphorus entering our lakes.
Other ways to increase infiltration are retrofitting buildings with green roofs, installing rain gardens on public property, as well as encouraging such actions for county residents.
An evaluation of zoning and building requirements to increase permeable surfaces on construction which could include installing green roofs, and permeable pavement.
This is the displacement of water from one point to another, through a diversion mechanism such as a pipeline. This option needs a lot more study, before proceeding. The map in the report, figure 27, shows the pipeline going through a wetland considered to be a national treasure by many organizations. Pumping in a different location may be a viable option, but a lot more information is needed before proceeding.
Concern over the redirected water is significant and alternative routes have been discussed. Dr. Zedler, author of Waubesa Wetlands: A New Look at an Old Gem (available on the Town of Dunn website), warned us of the churning that can happen as a result of displaced water which can upset the delicate ecosystem, as well as biological concerns, especially as they relates to invasive species.
Long-term (5–10 years) — WiDNR Lake Level Evaluation
The consideration of lowering Lake Mendota for storage is a longer-term decision, and not feasible until there is a way to move water out of the system. For this reason, I would move forward with increasing the ability to move water out of the system first, evaluate that progress, and then re-evaluate the need and possibility of lowering the lake levels. The process of lowering lake levels will be slow due the need for the Wisconsin DNR to conduct a complete study to update the targets set in 1979. It might make sense to move forward with initiating this project, since it is a slow process.
What does the action look like?
The Task Force will make recommendations that are intended to be reviewed by Lakes and Watershed Commission and Environment Agriculture and Natural Resources (EANR). A resolution, or possibly an ordinance, can be drafted to be approved by the Dane County Board. Here is what I would like to see in that resolution:
Begin the process to obtain dredging permits
Model and evaluate infiltration (wetlands, permeable pavement, etc.) scenarios — how much land is needed to have the necessary impact. Evaluate the feasibility of such an approach.
Evaluate the possibility of acceptable routes for pumping that do not harm sensitive wetlands, complete a full environmental impact study of any of those proposed routes.
Explore the impact of building and zoning regulations to increase permeable surfaces.
Set a requirement to re-evaluate lake levels with new data, after mitigation actions are taken, and in partnership with the DNR.
Extend the time that the Lake Level Task Force meets in order to oversee the progress of these recommendations, and evaluate the impact of the changes.
What is missing? What would you like to see in what I advocate for in the final two meetings of the Lake Level Task Force?
What can you and I do in the meantime?
In the Spring 2019 Nature Conservancy Magazine, you can find an article titled Planning for a Rainy Day. In the article you will learn more about the power of rain gardens, and green roofs: steps we can all take to helping to absorb rainwater. An example of action that can be taken is the recent approval by the Sustainability Subcommittee to install a green roof on the City County Building. Thanks to Dr. Zedler for speaking and brining this to our attention.