SNOHOMISH — A pro will be advising the county on how to solve trouble with invasive plants in Lake Roesiger northeast of Snohomish.
The lake has weed problems with stringy milfoil and a rash of floating water lilies. If left unattended, both can choke the lake’s oxygen and damage the lake’s ecosystem.
Other non-native plants on the shoreline are yellow flag iris; and purple loosestrife, which crowds native plants. Unwanted clams, mussels and snails introduced into the lake are here, too.
This summer, lake scientists will write a recommendation report called an Integrated Aquatic Vegetation Management Plan, explained Snohomish County Surface Water Management Water Quality Specialist Marisa Burghdoff.
The county will also form a steering committee and hold public meetings to review the recommendations. The formal path for action and implementation should be decided sometime this fall.
Shoreline homeowners in the Lake Roesiger Community and Boat Club petitioned the county for help, and the study is one step.
The county won a $30,000 grant from the state Department of Ecology toward paying for the study, and will seek a $70,000 grant toward acting on the plan. The action grant requires the club to contribute $17,000 in matching funds. It is soliciting the public for donations. (The club pitched in $7,500 for the grant for the study.)
At 348 acres, Lake Roesiger is the third-largest natural lake in the county.
There is an estimated 26 acres of fragrant water lilies that have made a layer in the middle basin, Burghdoff said.
The trouble with lilypads is they grow into dense canopies that exclude other local plants as well as slow water circulation, which degrades oxygen levels, Burghdoff said.
Milfoil, meanwhile, is one of the most devilish to eradicate: it is capable of colonizing entire lake areas. Tiny fragments of broken milfoil can regrow, meaning it propagates quickly. Enough of it can overpower native plants.
If you’ve been on a lake that has milfoil, you’d recognize the plant as the hair-like strands that get pulled up on fishing hooks or annoy while swimming. It spreads lake-to-lake when it tangles itself in boat motors.
The county was controlling milfoil at Lake Roesiger for many years but stopped when county budget cuts in 2018 ended the program.
The county was controlling milfoil at Lake Roesiger for many years but stopped when county budget cuts in 2018 ended the program.
The all-volunteer Lake Roesiger club began hiring divers to pull out milfoil on its own dime as best it can. The county’s grant application to Ecology indicates these efforts are getting overpowered.
Lena Coleman-Meyer, the club’s Lake Health Committee chair, said the upcoming study is “going to be wonderful to look at everything.” She can see the acres of lilypads from her back door.
Separate from invasive weeds, a county report card says Lake Roesiger’s water quality is in great shape when it comes to water clarity and toxic algae bloom risks.
How to help
The all-volunteer Lake Roesiger Community Club asks for donations to help it meet the $17,000 needed for its matching contribution for the upcoming lake-fix implementation grant. To donate, go to www.LakeRoesigerCommunityClub.org and
click on the PayPal donation button at the bottom of the webpage.
Tips from Snohomish County
Prevent spreading invasive species. When boating, clean, drain and dry your boat before launching and before leaving:
• Clean – Remove all aquatic plants, animals and mud
• Drain – drain all water from your boat, trailer, wells, bilge before leaving the area
• Dry – allow time for your boat to be completely dry before launching in other waters.
