36 CFR § 7.9 - St. Croix National Scenic Rivers.
(a) Snowmobiles. After consideration of existing special situations, i.e., depth of snow or thickness of ice, and depending on local weather conditions, the superintendent may allow the use of snowmobiles on the frozen surface of the Saint Croix River on those sections normally used by motor boats during other seasons, between the Boomsite and Highway 243 near Osceola, Wisconsin, and Saint Croix Falls to Riverside, Wisconsin, and in those areas where county or other established snowmobile trails need to cross the riverway or riverway lands to connect with other established snowmobile trails.
(1) Entering by vessel, launching a vessel, operating a vessel, or knowingly allowing another person to enter, launch or operate a vessel, or attempting to do any of these activities in park area waters when that vessel or the trailer or the carrier of that vessel has been in water infested or contaminated with aquatic nuisance species, except as provided in paragraph (c)(2) of this section is prohibited.
(2) Vessels, trailers or other carriers of vessels wishing to enter park area waters from aquatic nuisance species contaminated or infested waters may enter after being inspected and cleaned using the technique or process appropriate to the nuisance species.
(d) Placing or dumping, or attempting to place or dump, bait containers, live wells, or other water-holding devises that are or were filled with waters holding or contaminated by aquatic nuisance species is prohibited.
(e) Using a wet suit or associated water use and diving equipment previously used in waters infested with aquatic nuisance species prior to being inspected and cleaned using a process appropriate to the nuisance species is prohibited.
(f) For the purpose of this section:
(1) The term aquatic nuisance species means the zebra mussel, purple loosestrife and Eurasian watermilfoil;
(2) The term vessel means every type or description of craft on the water used or capable of being used as a means of transportation, including seaplanes, when on the water, and buoyant devises permitting or capable of free flotation.