Fed up with weed growth at the lake, Minnesota's shoreline property owners are reaching more and more for jet-like water thrusters to uproot vegetation and spruce up the wading areas around their docks.

Selling for as much as $4,000 per unit, the high-­powered water blasters are strong enough in some cases to excavate lake bottoms. When they deliver a clean sweep in front of a given cabin, the machines tend to crop up elsewhere on the same lake.

Now the trend is eliciting a crackdown by the state Department of Natural Resources. The agency's Aquatic Plant Management Program warned in a recent news release that it's an affront to nature and against state law to deploy hydraulic jets to uproot aquatic plants or scour away sediment and muck.

"There's been a number of recent citations and warnings,'' said Jonathan Hansen, a DNR Fish and Wildlife official.

Conservation Officer Shane Osborne of Evansville reported Monday that he tagged various lake lot owners in his area during a recent inspection tour with a DNR aquatic plant specialist.

"Violations were found with people running Aqua Thrusters … spraying cattails with herbicides, operating weed rollers without permits, and mechanically controlling aquatic plants without permits,'' Osborne wrote.

Hansen said back-to-back short winters have boosted plant growth in many lakes, providing longer growing seasons. In some areas, above-average rainfall has washed nutrients into lakes to exacerbate the growth. Coupled with increased disposable income from a healthy economy, propeller-­driven hydro sweepers have grown in popularity, Hansen said.

Cabin owners can obtain DNR permits to mechanically remove weeds, or poison them, but only within limits. The laws are meant to grant people reasonable lake access while also protecting fish habitat and preserving enough plants to stop shoreline erosion and to absorb excess nutrients. Demand for the permits in 2017 is higher than usual, Hansen said.

According to the DNR, a person may legally operate a hydraulic jet if it's placed high enough off the lake bed so that it doesn't move sediment or destroy rooted aquatic plants. It must be directed parallel to the water's surface, or upward. In that position, the jets can move dead vegetation and duckweed away from docks and shorelines.