This blog post was written by UW-Madison undergraduate student Lindsay Summers, who worked at WGNHS as a social media and geology Assistant for two years before graduating in 2023. Includes March 2024 update from Elmo Rawling, Chelsea Volpano, and Mel Reusche.
Being from Cleveland, Wisconsin, my entire childhood was spent along the coast of Lake Michigan. Not only did the beach inspire my love for geology, but all of the roads, houses, and activities in my hometown evolved around the coast and the bluffs. When I was 13 years old, an important road that my family used almost every day along the coast of Lake Michigan had to be moved away from the bluffs due to dangerous coastal erosion. This construction project took a lot of time, energy, and resources—something I’m sure other locals remember vividly. But I had the same questions at 13 that I have now:
How much will erosion affect Wisconsin communities in the future? And what’s being done about it?
In 2021, while a student at UW-Madison, I had the chance to learn more about this issue. I met with project leader J. Elmo Rawling III, a geomorphologist at WGNHS, and UW-Madison PhD candidate Chelsea Volpano during their fieldwork regarding onshore erosion and nearshore sand transport to find detailed answers to these questions. The record high lake levels in 2020 caused a major increase in shoreline erosion, which prompted thousands of dollars in damages to homes and communities. High lake levels and shoreline erosion also cause sand to be deposited in harbors along the Wisconsin coast, which becomes an expensive, labor-intensive issue when the lake level drops.
Gathering data by boat
The research project on shoreline erosion had started at Point Beach State Forest near Two Rivers, mainly because, as Chelsea explained, “it is a big accumulation of sand on a natural shoreline.” For this reason, Chelsea and Elmo are studying similar processes at a second location in Port Washington since it also has a natural coastline. A considerable number of shorelines on the coast of Wisconsin have been altered by humans for various reasons, which can affect the movement of water and sediment. Since the sites in Point Beach State Forest and Port Washington are in their natural states, they are ideal for this research.
The data collection process for this project is not only done in striking locations—it’s also very interesting and fairly simple to understand, with no prior knowledge in geology required. First, a boat (either a kayak that Chelsea uses when it’s warm, or a small remote-controlled one during cold weather) containing a Single Beam Echo Sounder equipped with a highly accurate GPS unit sends out a ‘ping’ at 10 times per second. The time it takes for the ‘ping’ to hit the bottom of the lake and come back is then recorded, along with the GPS location, using software created by Chelsea and UW-Madison Instrument Technologist Neil Lord. The laptop recording the pings rides in the boat, connected to the GPS and sonar. To perform the data collection survey, Chelsea steers the boat in a grid pattern along the shore for 1 km, using evenly spaced flags to mark where to turn (see the illustration below). Then, after data collection is finished, Chelsea creates a visual of the bathymetry (a map of the depths of the lakebed) for analysis.
As of March 2024, the team has conducted several surveys that document high lake level and low wave energy conditions. According to Chelsea, “There’s not a lot of volume moved during low lake levels, but we do see the reorganization of nearshore bars. This is pretty interesting because the bars can dampen the impact of large waves on the coast, depending on where they’re located.” One goal is to capture data after a large storm in order to understand how the location of sand bars affects coastal erosion in multiple situations and conditions, especially since storms can cause the most damage. Unfortunately, while attempting to gather post-storm data, the connection to the boat was lost (and then found!). In the long-term future, the goal is to do similar research at other locations along the Wisconsin coast, and also create a model for bluff erosion so that more people can understand the specific effects that erosion can have on bluffs.
The future of bluff erosion
Another important topic of discussion, especially when it comes to water levels, is climate change, so I made sure to ask Chelsea how she expects climate change to affect lake levels. She explained that it is difficult to predict lake levels very far into the future, but based on historical records it will likely continue to fluctuate. However, “With climate change, the general expectation is that these cycles will become more frequent and occur more quickly. So we might go from low to high very quickly. We see extensive erosion when lake level changes quickly, so with climate change we’ll probably be dealing with coastal erosion more consistently,” explained Chelsea via email. In other words, like many matters regarding climate change, its effects will make the pre-existing situation more drastic and harder to manage. But luckily, the more we know about coastal erosion from this research project, the more prepared we will be if erosion happens more frequently.
Currently, the bluff erosion near the road that the residents of Cleveland frequently use poses no threat to drivers. However, since this erosion continues to persist and happen more consistently, it will inevitably become a threat again in the future. Furthermore, it will likely require more expensive and time-consuming plans to adapt to it, including movement of the road itself along with the houses surrounding it. This recurring and costly problem is familiar along the Wisconsin coasts of Lake Michigan and Lake Superior. With the information being gathered from this research project, erosion events and the effects they have on shorelines will become more predictable, and hopefully less impactful.
Learn more about this ongoing research
- Gaining a big picture of bluff erosion and sand movement along Lake Michigan (UW Sea Grant, 2023)
- Fishing for landslides (UW Sea Grant, 2017)