Program managers from Clear Lake Solutions successfully coordinated the eradication of Eurasian Water Milfoil from Dolphin Lake, BC. utilizing an environmentally sensitive, Health Canada approved, and Ministry of Environment endorsed, herbicide. The program was reviewed with all relevant government authorities, stakeholders and local residents prior to application. Only the invasive Eurasian Water Milfoil was impacted. No other flora or fauna were harmed. The program was a complete success.
Background on the Project
Dolphin Lake is located in the Fairwinds community of Nanoose Bay, BC. In 2015 the lake was overgrown with an “invasive species” of plant. By 2016 the infestation was significantly more pronounced. (see pictures below) The impact of unrestricted growth of vegetation in the lake could potentially have far reaching consequences for many stakeholders. It threatened to choke out other native plants, reduce the clarity of the lake water, infest connected golf course water ponds and irrigation systems. If left to grow exponentially it would negatively impact home owner property values as well as overall quality of life in the community.
Clear Lake Solutions gets involved
A group of concerned residents who would go on to form Clear Lake Solutions reviewed the problem and agreed that the invasive plant had to be eliminated.
Clear Lake Solutions (CLS) broke the project into the following 5 distinct phases:
- Data Collection, Analysis (water & plant) and Root Cause Determination
- Information Dissemination (Owners, Residents, Government Officials)
- Remediation Option Review and Recommendations to owners, residents, government officials
- Proposal Preparation, Presentation and Approvals
- Program Implementation and Ongoing Maintenance
Data Collection and Analysis
Samples of the “invasive species” were obtained from the lake for analysis. We determined that the aquatic plant was Eurasian Water Milfoil.
Lake Water Analysis
Water samples were also taken from the lake and analyzed for pH, turbidity, conductivity, metals, phosphorus compounds, chlorophyll “a” and total organic carbon (TOC). The purpose of the testing was to compare current water quality in Dolphin Lake to “baseline” data obtained from previously published material. The analysis results determined that the Dolphin Lake phosphorous content was approximately 170 per cent greater than Enos Lake which feeds Dolphin Lake. Phosphorus is a major nutrient promoting the growth of aquatic plants. This level of phosphorus is much higher than typical raw lake water.
Date stamped photographs of the lake were taken to document the progress of the infestation.
CLS contacted the owners of the lake bottom, the Ministry of Environment, the Department of Fisheries and the Regional District of Nanaimo (RDN) informing them of the infestation of the lake and outlined potential options.
CLS reviewed the following statistics governing invasive species in BC waterways:
- Water Sustainability Act and Regulations (SBC 2014, C.15) (BC Reg 36 / 2016)
- Invasive Plants Regulations (BC Reg 18 / 2004)
- Integrated Pest Management Act (SBC 2003 C.58))
- Weed Control Regulation ( BC Reg 189 / 2001)
- Community Charter – Spheres of Concurrent Jurisdiction – Environment and Wildlife Regulations (BC Reg. 144 / 2004)
- Water Quality Act
- Enos Lake Water Quality Report
We prepared a Powerpoint presentation and met with the lake “owners” management team, community associations, government officials from Forestry Lands & Natural Resources (FLNRO), the Ministry of Environment (MOE). We also communicated with the Invasive Species Council of BC, local residents and Front Counter BC Government representatives.
Potential Mitigation Options
Clear Lake Solutions reviewed a number of mitigation programs for control and/or eradication of the Eurasian Water Milfoil infestation in Dolphin Lake. These options broadly fell into three categories:
- Biological Control
- Chemical Control
- Systemic / Mechanical Control
- Biological Control Methods
1.1 Milfoil Weevils
Milfoil Weevils have been used to control Eurasian Water Milfoil in the US but not in BC and only a few times in the rest of Canada.
According to Forestry, Lands and Natural Resources (FLNRO) …” there are currently no insects registered for this purpose in BC and, given the genetic similarities between invasive and native milfoils, it is highly unlikely that there will be any insects approved for this purpose in future.”
Nevertheless, proponents can submit an application to use Insects to control invasive plants if they desire through the Introduction and Transfers Committee (ITC). The request will be reviewed by science staff and biocontrol experts in both the Federal and Provincial Government. Supplementary information will also be required.
1.2 Sterile Triploid Carp
Sterile triploid carp have been used to control Eurasian Water Milfoil in Alberta and the US but not in BC. Government officials have stated: ….” grass carp introduction is not a recommended treatment option for milfoil, and is not something the Inter-Ministry Invasive Species Working Group would support, or the DFO Aquatic Introductions and Transfers Committee would likely permit.
- Chemical Control Methods
The Pest Management Regulatory Authority (PMRA) within Health Canada (HC) deals with herbicide regulations. A chemical that is approved for use in aquatic waterways and registered with the HC PMRA can be applied to public waterways if a Provincial Pesticide Use Permit is issued from the provincial Ministry of Environment.
If a body of water is self contained, privately owned and outflow can be controlled it can be considered a self-contained lake. Privately owned self-contained lakes do not require permits to be treated with a Health Canada approved herbicide.
3.1 Mechanical Control
The Regional District of Kootney Boundary (RDKB) have been using divers to de-root Milfoil in Christina Lake for a number of years. Once the diver(s) de-root the material it is harvested on shore.
The use of a mechanical harvester and/or divers to de-root the Eurasian milfoil require a permit that must be obtained by submitting and application to: http://www.frontcounterbc.gov.bc.ca/ . The process is the same for both methods.
There is significant literature on the successful application of aquatic dyes in infested waterways. The dye creates a 4-foot shade barrier that kills the Eurasian Water Milfoil by preventing photosynthesis. One major advantage of dye is that it has been used successfully on golf courses and it is not classed as a herbicide.
3.3 Benthic Barriers
Benthic barriers, either applied to the surface of the water or the lake bed act in the same way as dyes… they interrupt the photosynthesis of the Eurasian Water Milfoil.
Treatment Decision and Program Implementation
After a, thorough review of all options Clear Lake Solutions determined that herbicide application would be the most cost effective and efficient treatment method for this particular situation. It was reviewed with various stakeholders and decided that the ponds would be treated with a Health Canada and Pesticide Management Regulatory Authority endorsed chemical herbicide.
Clear Lake Solutions contacted a government certified chemical application company and requested a treatment proposal in early 2017.
Clear Lake Solutions, golf course staff and the contractor monitored the milfoil growth and determined the best locations for effective treatment. This information was used to determine the timing of treatments and adjust plans and actions to ensure the removal of milfoil from Lake.
The applicator mounted a 60-liter sprayer with a handgun and boom buster nozzle on a small vessel to treat most of the milfoil. Back pack and hand-held sprayers were used to treat smaller patches of milfoil that could be reached from shore.
One crew person ran the mounted sprayer while a second crew person mixed and delivered the herbicides.
The first treatment occurred once the milfoil began to actively grow in early May.
To avoid oxygen deprivation from decaying vegetation only ½ of Dolphin Lake was treated with the first pass.
The results have been excellent.
Clear Lake Solutions was successful in eradicating an invasive aquatic plant that infested a local water way. Clear Lake Solutions utilized a structured problem-solving approach to determine the invasive species, analyze the water and review relevant treatment options. Clear Lake Solutions worked with the owner of the lake, various levels of government and local residents to communicate the problem and layout the options. Clear Lake Solutions recommended chemical treatment with a Health Canada approved herbicide that targets Eurasian Water Milfoil. Clear Lake Solutions contacted a government certified chemical applicator and provided all the data necessary to prepare a treatment proposal. Clear Lake Solutions worked with the government, owners and applicators to ensure an effective and environmentally sensitive treatment program that has proven to be 100 % successful.
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