Creating the Lake Roesiger Invasive Plant Management Plan

In 2021, Snohomish County with input from the Lake Roesiger community developed a comprehensive plan to address the invasive aquatic plants at Lake Roesiger. View the items below to learn more about the plan and the current locations of invasive aquatic plants. 


Roesiger-IAVMP-resize800-600 Opens in new window
Full Plan 
Roesiger Draft Invasive Aquatic Plant Control Plan Opens in new window

Map of Plants
Roesiger Lily Map Test Opens in new window


Below is a history of control efforts, the plan development and all related presentations, meetings and community surveys. 

Historic Invasive Plant Control Efforts

Since 1998 Snohomish County controlled Eurasian watermilfoil in the lake through diver surveying and hand-pulling. These efforts were effective in keeping milfoil levels low with only small patches growing each year. Unfortunately, funding for this program was lost in 2017. The Community Club has raised funds to hire divers for some hand-pulling work in 2019 and 2021.


Over the years, some individuals have worked to control fragrant waterlilies in from of their properties. However, the problem has persisted and there was a growing desire to have a larger solution. In recent years, the Community Club has purchased tools for homeowners to do lily control on their property and obtained a larger permit for participating landowners to lay bottom barriers. While these efforts may provide relief in small areas, they are not addressing the large scale infestation.


Plan Development 

In 2020, the community approached the County for assistance in applying for a  Washington State Department of Ecology grant program to help fund invasive plant control. The County applied for and was awarded a grant beginning in July 2021. The plan is focused on long-term control of key invasive plants and was developed with in-depth community engagement of all area residents as well as lake users. 


The plan was approved  by 64% of all voters which included lake users that do not live near the lake. Approval was 70% among lake area residents and 74% among Lake Roesiger Community and Boat Club members. The Washington Department of Ecology approved the plan in February of 2022. 


Plan Goal & Steps 

Roesiger Plan Timeline Of Actions

The project goal was to provide the community with a road map which will help native plants, ecosystem health, and lake recreation. The plan laid out all options with associated costs and benefits so the community could decide on the best path forward. 


Step 1

Map Invasive Species

In July 2021, County staff conducted a survey of the lake mapping all locations of identified invasive species as well as inventorying the native plant species. These maps were used to assist in the plan development and can be viewed online:

Step 2

Develop Draft Management Plan

Snohomish County contracted with Tetra Tech Inc. and ESA to develop the draft plan. Tetra Tech and ESA have extensive experience managing invasive aquatic plants including knowledge of the latest research in control technology. They also have experience working with local communities to facilitate development of  IAVMPs. 


Members of the Lake Roesiger Community and Boat Club were instrumental in developing the draft plan. The Club appointed a steering committee of 12 members with representation from each lake basin. The committee met twice to 1) provide input to Tetra Tech and ESA regarding the plan goals and 2) review the draft plan and develop recommendations for the full lake community. 


  • Steering Committee Meeting 1: August 9, 2021 - development of plan goals and control options. Watch the recorded meeting and view the presentation.
  • Steering Committee Meeting 2: Scheduled September 9, 2021 -  review draft management plan and develop recommendations. Watch the recorded meeting and view the presentation.
Step 3

Present Draft Plan to Community for Input

The plan was drafted and included four different scenarios for plant control. Tetra Tech  and ESA provided an online presentation to explain the plan and the potential management options. The entire lake community was invited via mail, email, and social media postings to view the presentation and the draft plan and provide feedback via an online survey. 

Finally, there was a lake-wide community on October 26th to review the plan feedback and discuss next steps.  Watch the recorded meeting.

Step 4

The community input was used to revise the plan and a final community vote approved the plan.