Hennepin County is taking a new approach to encourage lake users to join its massive campaign to control the spread of invasive species in its waters.

The county last year developed the "Lake Pledge" website and app, which encourages people to submit information about their favorite lake and the activities they enjoy. Users receive digital badges for watching videos on how to stop the spread of invasive species.

"We have an amazing water resource in Hennepin County," said Tony Brough, the county's invasive species prevention program coordinator. "Many metropolitan cities do not have the fantastic lakes like we do. They are worth protecting."

Hennepin County is a rare urban area with an abundance of options for people to boat, kayak, water scooter and own a lakeshore home. Besides 200 lakes, it has 640 miles of streams, three major rivers, 45,000 acres of wetlands and 50 public accesses for boats and trailers.

With all that water and all the use, county officials have made a top priority of preventing the spread of aquatic invasive species such as zebra mussel, Eurasian watermilfoil and carp.

Aquatic invasive species can damage native fish and plant populations, but also threaten human health and hurt property values.

The county deploys a variety of strategies to spot and control invasive species, including flying drones, sending inspectors to randomly check boats and installing cleaning stations at public access areas.

But county officials knew they could do more by turning lake lovers into allies with the "Lake Pledge."

The program expanded in July, starting as a pilot with Weaver, Cedar Island and Fish lakes in Maple Grove. But now people can take the pledge with any lake in the county.

So far, 375 people have either signed up on the website and watched videos or agreed to pledge to a lake.

The pledge website and app start with the person logging on, choosing a lake or other body of water and listing what activities they enjoy. It also asks if the person is a lakeshore property owner, has an aquarium tank, fishes with live bait and can identify zebra mussels or milfoil.

The results of the data are displayed on the website and app. For example, 90% of the participants said they could recognize zebra mussels. The person has to make a final submission on the sites to pledge a lake.

Brough said the sites show the many pathways that allow invasive species to get into waterways, including people not cleaning off water toys and kayaks, and dumping their aquarium fish into a stream or lake.

For the pilot project, Brough approached Andy Siffert, president of the Weaver Lake Conservation Association.

Siffert joked that at first it became a competition with Maple Grove's other two lakes to see who get the most lake pledges. Of the association's 106 members, 57% have taken the pledge.

"We are a very active lake association," Siffert said. "We work closely with city officials and knew it would be great to give them a solid figure on our number of pledges. It should also help to get future funding for projects. We didn't see a negative side whatsoever."

The city recently upgraded Weaver Lake's boat launch, and Siffert said it also bought new boat cleaning equipment to remove any possible invasive species that is similar to what would be found at bigger lakes.

"When we go door to door to collect lake association dues, we can ask people if they have taken the lake pledge," he said. "I have two kids and want to leave Weaver Lake in the best shape I can."

Minnesota appropriates $10 million annually to prevent the spread of invasive species. This year, Hennepin County received $314,000, which is used for research, early species detection, pathway analysis, education, boat cleaning equipment and inspections.

The county started a pilot program in 2017 to monitor how often people used the equipment at its 20 stations. The total reached 100,000 tool uses last fall.

Brough said he scratched out the idea of the Lake Pledge program on a napkin and it sat in his computer bag for a few months. He then ran the idea past county staffers and the heads of several lake associations. While fishing on Lake Minnetonka, he saw the damage zebra mussels can do.

This is why Lake Pledge is an important and affordable tool in the county's effort to continue the fight against invasive species, he said.

"If the county had inspectors at all the public access points during the boating season, it would cost $2 million," Brough said.