Update: Terra Vigilis Studies On Wake Boat Activity

Several years ago, our organization began receiving community inquiries about the environmental impact of wake boats operating in surf mode on Lake Waramaug. Recognizing the complexity of the issue, we committed resources to undertake further study, and to share findings with the community.

We're a small organization, employing one full-time and one part-time scientist. As such, we typically engages expert consultants for complex studies. After careful evaluation, we identified Terra Vigilis as the best partner for this work. Ultimately, the towns of Washington, Warren, and Kent decided to contract Terra Vigilis directly through the Lake Waramaug Interlocal Commission. Their full report was released on December 16, 2024.

Since Lake Waramaug is primarily fed by Sucker Brook, we expend considerable resources on monitoring and remediating the brook’s watershed and streambed. As Terra Vigilis was conducting an in-lake study for the three towns, the Task Force further engaged Terra Vigilis to investigate the impact of large waves on the Sucker Brook delta. The findings from that study are available here.

Key Findings

The Terra Vigilis reports conclude that powerful waves impacting the shore and strong propeller downwash can cause harm to the lake. Powerful waves erode the shoreline and shallows, while propeller downwash scours the lakebed, reducing water clarity and releasing harmful nutrients normally trapped in sediment. These effects are particularly severe in shallow areas like the Sucker Brook delta, where wave energy is dissipated by “scrubbing” the bottom. Preventing erosion and minimizing nutrient release are core goals of ours, as erosion reduces water clarity, and nutrient release increases the risk of toxic algae blooms. The Terra Vigilis findings are consistent with multiple other studies. 

Unanswered Questions

• The Terra Vigilis studies compared the impact of wake boats operating in surf mode to ski boats operating on plane, but not to ski boats transitioning to plane, nor to boats engaged in tubing off-plane.  

• The Terra Vigilis studies were not designed to evaluate the potential impact of wake boats operating in surf mode relative to the impact of natural, wind-driven wave action.*

Water Quality Trends

We have tracked water clarity and phosphorus concentration (both key indicators of lake health) since 1977. Over this time, the data show a trend of improvement in both clarity and phosphorus concentrations (clarity increases and phosphorus decreases). We further examined rolling five-year averages of these parameters. The data suggests that water quality was most favorable in the two most recent five-year windows (the last decade split from 2015 to 2019, and 2020 to 2024), although phosphorus concentration in the upper stratum of the lake was relatively consistent from 2000 onwards. When examined on a year-by-year basis, average water clarity slightly decreased from 2015 to 2024, and decreased more sharply from 2020 to 2024. However these year-by-year trends are variable and reflect declines from the exceptionally clear years of 2019 and 2020. Year-by-year phosphorus data suggest slight improvement (decrease) from 2014 to 2024, but a slight worsening (increase) from 2020 to 2024. A more detailed report of this analysis is available here.  

In sum, the data indicate long term and overall improvement of water quality in Lake Waramaug, with recent years exhibiting high variability and perhaps a slight decline per our indices, albeit from very good levels achieved in the past few decades. With the data available it is unfortunately impossible to ascribe changes in water quality to any one cause, be it wake surfing or other motorized recreational activity, weather events, or property development.  

Conclusion

We endorse the Terra Vigilis findings, but defer to the three towns to decide whether to implement the Action Items listed in the report’s Section 5 ‘Lake Waramaug Impact Management Issues for Consideration’ on pages 24-25. If action is taken, the Task Force strongly suggests particular attention be paid to protecting shallow water areas like the Sucker Brook delta from all wakes.

*The Terra Vigilis Lake Waramaug Shallow Water study did cite work done by Water Environmental Consultants, SC in 2021 as follows: “Wakesurfing vessel wakes exceed wind waves at every site at distances within 500 feet of the vessel sailing line. In contrast, typical cruising vessel wakes do not exceed wind waves at every site, except within a very close proximity to the vessel, i.e., 75 feet.” 

Additional information on large wave recreational activities and its potential impact to the lake, are below.

Video on TVES Reports

Reference Materials We Reviewed:

Connecticut

• Terra Vigilis Lake Waramaug Wave Impact Study Final Report

• Terra Vigilis Lake Waramuag Shallow Water Environment Wave Impact Study Final Report

• Short Video on Two TVES Reports Above

• Lake Waramaug User Survey (From Warren, Washington and Kent)

Wisconsin

• Terra Vigilis North Lake Management District study

• Summary of Wake Boat Impact Studies, W. Scott Brown

Chesapeake Bay

• Defining boat wake impacts on shoreline stability toward management and policy solutions

• Review of boat wake wave impacts on shoreline erosion and potential solutions for the Chesapeake Bay

Michigan 

• Department of Natural Resources, Wake Boats: concerns and recommendations related to natural resource management in Michigan Waters, September 2022

Minnesota

• Minnesota Study of Wake Boat Waves

• Own Your Wake: Example of a Public Safety Campaign 

New Hampshire

• Final Report of the State Wake Boat Commission to Study Wake Boats

• The above report has a list of great resources at the end. Here are a few of our favorites:

  • Project Evaluation of the Impact of Waves Created by Wake Boats on the Shores of the Lakes Memphremagog and Lovering

  • Wakeboat: Having Fun while Making the Right Choices

Other

• BoatUS Wakeboat Etiquette Article (includes links to additional wake boating articles)