So far, the biggest aquatic invasive species problem the Minneapolis Park and Recreation Board has had to deal with is Eurasian Milfoil . 

But since it's hard to manage nasty things like Zebra Mussels  and Viral Hemorrhagic Septicemia  with a floating, overgrown lawnmower, the Park Board on Thursday decided on a set of "emergency" measures to forestall further invasions. Starting July 13, every boat ramp at Lakes Calhoun, Harriet, and Nokomis will be chained shut, with no boaters allowed onto the water without first being inspected by a Park Board official.

“The lakes are the crown jewels of our park system, so protecting them from aquatic invasive species is a very high priority for our Board,” said Park Board president John Erwin, in a statement emailed to reporters. “We all can see the detrimental impact of milfoil on our lakes, and the Park Board is committed to ensuring that our lakes can be enjoyed for years to come by protecting them from new invasive species.”

The inspectors will be at the ramps from 6:00 a.m. to 10:00 a.m. and 5:00 p.m. to 9:00 p.m. on Mondays through Thursdays, and from 6:00 a.m. to 9:00 p.m. on Fridays through Sundays. Inspections will cease after Sept. 30.

Minnehaha Creek and its parent, Lake Minnetonka, are both already infested with milfoil and Zebra Mussels, according to a list maintained by the Department of Natural Resources.