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Originally published in the Ozaukee County News Graphic

Almost nothing is more harmful to a river than a dam. These aging structures choke the life from waterways—disrupting natural flows, degrading water quality, and blocking fish and wildlife from moving freely. Across the U.S., more than 500,000 dams stand in our rivers, and a staggering 85% of them are outdated, crumbling, and often dangerous. In just the past few years, catastrophic dam failures have devastated communities and caused millions in damages—grim reminders of the urgent need to rethink our relationship with these barriers.

Wisconsin has around 4,000 dams. More than 200 of these, including the Woolen Mills Dam in Cedarburg, are classified as high hazard by the Wisconsin Department of Natural Resources (WDNR)—meaning their failure could result in loss of life or significant property damage. Alarmingly, the Woolen Mills Dam cannot currently withstand even a 100-year flood event, falling well short of the 1,000-year flood event threshold now required for high hazard structures. This poses serious risks to residents, especially as our state experiences more intense and frequent rainstorms.

There are no dams in the Milwaukee River Basin that are profitable, in terms of providing hydropower, water supply or other critical functions; most, like the Woolen Mills Dam, had historic industrial uses—powering woolen, grist, or lumber mills—that no longer exist. The existing Woolen Mills Dam is actually the third dam built at this site. The original dam that powered the mill washed out in 1870; the second failed in 1933. The current structure was built around 1939—nearly 40 years after the mill shut down—to create a swimming pond, which has since closed due to poor water quality. Today, the dam serves no practical purpose beyond preserving an artificial impoundment that continues to degrade river health.

Despite this, deciding to remove this dam has been a difficult choice. This dam, like many others, is tied to the community’s history and identity, but public safety, environmental health, and long-term economic sustainability should guide the decision to remove it. 

Here’s why removing a dam often makes far more sense than trying to repair it:

Public Safety

Since 2000, Wisconsin has seen 34 dam failures—28 of them since 2018—making it the second-highest failure rate in the country. The last decade has also been Wisconsin’s wettest on record, with rainfall increasing 17% since 1950. Many dams were never designed to withstand the weather extremes we’re now facing. The high hazard rating for the Woolen Mills Dam means expensive upgrades are required to safely pass large storm events, including a significant increase in spillway capacity. Given the dam’s confined location, there are few viable options. Retrofitting, repairing, or replacing the dam could cost millions, based on recent projects like the Columbia Mill Dam—and even then, repairs may only last 10–20 years and carry high annual maintenance costs.

Safety modifications such as “top gates” or lowering the height of the dam could reduce flood risk but introduce new concerns. Low-head dams are deceptively dangerous for paddlers and swimmers, creating powerful recirculating currents that have earned them the nickname "drowning machines."

Healthy Waterways

Dam removal is one of the most effective ways to restore rivers to health. It can reconnect fragmented ecosystems, improve water quality, and allow fish and wildlife to move freely once more. In Wisconsin, that means supporting species like northern pike, sturgeon, trout, bass, and native mussels. Removal can also lower water temperatures, increase oxygen levels, and reduce sediment and algae buildup. This, in turn, improves recreation, property values and public space. 

Resilient Rivers and Vibrant Recreation

Free-flowing rivers are better able to absorb and manage floodwaters, protecting nearby communities and improving resilience to climate change. Removal also opens the door for new outdoor recreation opportunities like paddling, fishing, and riverside trails. Often, there’s concern that a dam’s removal will “dry up” the river, but this is more perception than reality. After the Woolen Mills Dam failed in the 1930s, the river flowed freely for six years. Aerial photos from that period show the river was only slightly narrower than it is today.

Cost Savings

While dam removal has upfront costs, it is usually far less expensive than major repairs—especially when considering long-term maintenance, liability, and compliance with stricter safety regulations. It’s also a permanent solution that avoids the cycle of recurring costs and risk. Furthermore, state and federal grants are often available to communities pursuing removal, due to the ecological and safety benefits.

Despite the high hazard designation and aging infrastructure, the City of Cedarburg has never conducted a feasibility study for the Woolen Mill Dam—or the nearby Ruck Dam. Such a study would examine multiple alternatives: repair, removal, or constructing a fish passage. It’s a critical tool for evaluating the full picture: safety, cost, environmental impact, and community benefit. Cedarburg deserves that analysis, and it deserves to be part of a future that values restoration over risk and progress over patchwork.

Removing a dam—especially one that poses a clear threat to lives and property—is more than an environmental win. It’s a bold, forward-looking step toward safer communities, thriving ecosystems, and a more resilient relationship with our rivers.

Join us for another cleanup, hop aboard a kayak or grab your fishing pole and we’ll see you on the river!