Should we expand the Slow-No-Wake Shoreline Buffer?

As the number and types of Rock Lake users continue to grow, safety for all users can be improved by establishing a uniform Slow-No-Wake (SNW) buffer 200 feet from shore for all motorboats.  This will result in a very small increase of acreage reserved for Slow-No-Wake operation.  It will simplify the existing overlapping rules affecting swimmers, paddlers, motor boaters and, thus make the rules easier to understand and enforce.  It will also protect lake ecosystems and shorelines while improving Rock Lake’s aesthetics.

A proposal:  The Joint Rock Lake Committee (JRLC), which is a collaboration of the Town and City of Lake Mills, has recommended expansion of the current Slow-No-Wake buffer, from 100 to 200 feet, to the Lake Mills Town Board. The Rock Lake Improvement Association supports this recommendation.

The current situation is complicated. According to Wisconsin DNR regulations, Rock Lake’s shoreline, and people who enjoy the lake, are protected by a 100-foot Slow-No-Wake buffer.  In other words, motorboats are required to maintain Slow-No-Wake Speeds within 100 feet of the shoreline as well as 100 feet from piers, rafts, and swimming buoys.  For personal watercraft (PWC or jetski) this distance is 200 feet. Finally, all motorboats must maintain Slow-No-Wake Speeds within 100 feet of swimmers, wherever swimming is allowed.

map of Rock Lake
Orange & red highlights show areas of Rock Lake affected by the 200-foot SNW proposal. A detailed explanation is in first FAQ below.

In addition, Sensitive Areas as deemed Slow-No-Wake by Town of Lake Mills ordinance, include:
• Schultz Bay (northwest side)
• Korth Bay (southwest side) 
• the Mill Pond 
• Marsh Lake (the basin of the lake south of the Glacial Drumlin Trail)

Expanding the Slow-No-Wake area to 200 feet from shore
would:
• Establish the same buffer zone for both motorboats and PWCs.  This single regulation would be easier to understand and to enforce.
• Provide a safety buffer for swimmers and dogs, especially at Tyranena Park.
• Provide, in essence, a “Bike Lane” for distance swimmers and paddle sports enthusiasts.
• Move wake-producing motorboats farther from shore resulting in less disturbance to lake-bottom ecology and less shoreline erosion.

The impact of this change on lost acreage for unrestricted powerboating is estimated to be 24 acres, or less than 2.5% of the current unrestricted water surface.  Much of the shoreline not already protected by a Slow-No-Wake zone is riparian shoreline with piers.  Motorboats currently should maintain Slow-No-Wake Speeds 100 feet from the ends of those piers, or about 140 feet from the shoreline.  Therefore, a uniform 200-foot Slow-No-Wake ordinance would restrict less “open water” than one might think.

Why change now?  As a result of the current overlapping restrictions, it can be difficult to identify where the Slow-No-Wake area begins and ends.  Meanwhile, users of Rock Lake have continued to increase, and many have called for improved safety measures to protect all types of watercraft, fishing enthusiasts, swimmers, and even dogs whose owners use the lake for exercise and recreation.  One way to improve lake safety would be by a limited expansion (and simplification) of the Slow-No-Wake buffer.  This would also protect aquatic habitat for fish and other aquatic life and improve lake aesthetics.

Biggest safety concerns:
Use of the lake has changed.  There are more users of all kinds.
• Increase in paddle sports 
• Popularity of distance swimming
• More and faster pontoon boats  
• Increased popularity of wake/surf boats which create large wakes that stir up lake bottoms and may erode shorelines

Of particular concern:   Tyranena Park swimmers are allowed to swim 150 feet from shore yet power boats, at speed, are allowed to operate 100 feet from shore, unless the swimmers are easily seen.

Potential Next Steps: The Lake Mills Town Board sends the proposal to the WDNR for approval; a public hearing would follow.  Then the Town Board votes on the proposal.

Frequently Asked Questions:

 The Rock Lake Improvement Association calculates that the loss of open water would be minimal, less than 2.5%  of the lake’s acreage.  The impact of the changes are detailed here.

Slow-No-Wake Speed means a speed at which a vessel moves as slowly as possible while still maintaining steerage control.

Slow-No-Wake (SNW) benefits fall into two broad categories: Ecological (what’s good for the lake itself) and Recreational (what’s good for the community that is playing on/in the lake).  

Recreational:
Helps minimize conflict between various lake recreational users by creating a buffer from high-speed motorized users.  This buffer helps improve safety for the multiple users of the lake. Over the last five years, Rock Lake is seeing an increase in the number of paddle sport users (kayaks, canoes, stand up paddleboarders), open swimming, tubing and wakeboard boats, while water skiing and sailing have lessened.  Fishing is a constant.
A standardized SNW zone is easier to understand for recreational users rather than the current patchwork of zones.  The current policy is often cited by residents as most commonly violated.  These concerns were brought up in public comments and a public survey for the Rock Lake Management Plan. They are often mentioned to the patrol officers when those officers speak to community groups.  
-A larger SNW buffer can also reduce the noise level experienced by people on shore, or the passive users, which are the largest users of the lake.

Ecological:
-The major concern that SNW seeks to address is turbidity or the lake sediment getting kicked up and mixed into the water, especially in shallower water near shorelines.  When this happens, phosphorous that is bound in that sediment is released and can encourage algae blooms. The turbidity scours the gills of fish, interferes with fish who are sight hunters and also interferes with fish spawning. 
-Finally, waves reaching the shore contribute to shoreline erosion.
For more information on the ecological concerns, view the video in the last FAQ, below.

Absolutely.  According to the Clean Boat, Clean Water boat inspectors on Rock Lake, 36% of motorboats coming into Rock Lake were recently boating on a lake with 200-foot SNW rules.  These lakes include: Lake Ripley, Kegonsa, Waubesa, Monona, Mendota, and Lake Geneva.

Actually, adopting a 200-foot SNW buffer isn’t a ‘new’ idea.  In fact, Lake Ripley was an early adopter of a 200-foot SNW ordinance back in 1990.  At that time, jet skis were the fastest growing sector of the marine recreation industry.  Ripley updated their ordinance again in 2006.  This year, Lianna Spencer, their Lake Manager, stated that: “It (SNW) is currently (and has always been) perceived as an advantage to Lake Ripley; it helps prevent shoreline erosion and our residents view it as a good safety measure.”  Since 2000, motorized boats have gotten faster and larger.   In 2014, Dane county enacted  a 200-foot SNW on Lake Mendota, Monona, Waubesa, and Kegonsa.  Lake Geneva followed suit in 2017.

Currently, no.  Wakeboard boats are considered motorboats and subject to the same rules.  However, wakeboard boats create a larger wake which has an increased impact on shorelines and aquatic life in water less than 15 feet deep.  These impacts are being studied in other Wisconsin Lakes.  Here is a link to a contour map showing Rock Lake water depths.
For more information on the impact of wakeboard boats, view the video in the last FAQ, below.

Yes. This video presentation details a very interesting study of “enhanced” wave impacts on water quality and sediment re-deposition in a medium-sized freshwater lake in SE Wisconsin. It was created by Capt. Tim Tyre, PhD, USN(ret), Terra Vigilis Security Group & Prof. Mike Mortensen, Carroll University
Wave Propagation and Water Quality Impacts on Fresh Water Lakes

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