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TABLE OF CONTENTS
Surveys, Harvests, and Treatments
Eurasian watermilfoil (Myriophyllum spicatum) is an "exotic" aquatic plant. Exotic meaning that it is not native to this area, but it is native to Europe, Asia and Northern Africa. Eurasian watermilfoil has slender stems whorled by submersed feathery leaves and tiny flowers produced above the water surface. The flowers are located in the axils of the floral bracts, and are either four-petaled or without petals. The leaves are threadlike, typically uniform in diameter, and aggregated into a submersed terminal spike. The stem thickens below the inflorescence and doubles its width further down, often curving to lie parallel with the water surface. The fruits are four-jointed nut-like bodies. Without flowers or fruits, Eurasian watermilfoil is nearly impossible to distinguish from Northern watermilfoil. Eurasian watermilfoil has 9-21 pairs of leaflets per leaf, while Northern milfoil typically has 7-11 pairs of leaflets. Coontail is often mistaken for the milfoils, but does not have individual leaflets (Wisconsin Department of Natural Resources, 1999).
Eurasian watermilfoil reproduces by fragmentation, thus it does not rely on seed for reproduction. This reproduction allows for the plant fragments to be dispersed and carried by water currents and wind or inadvertently picked up by boaters. Milfoil reproduces extremely rapidly and can infest an entire lake within two years of introduction to the system (Washington State Department of Ecology, 2002). Milfoil is most commonly transported via boats, motors, trailers, bilges, live wells, or bait buckets, and if moist can stay alive for weeks. Eurasian milfoil is very invasive and can provide only a single habitat by replacing the native plant species and in turn threatening the integrity of aquatic communities. It also inhibits the aesthetic and recreational uses like swimming, boating, and fishing. Severely infested waters display a dense yellow-green matt of vegetation and give off the appearance that the water is "infested" or "dead." The decomposition of the plant mass at the end of the season results in nitrogen and phosphorus loading, and the cycling of nutrients from sediments to the water column by Eurasian watermilfoil may lead to deteriorating water quality and algae blooms of infested lakes (Wisconsin Department of Natural Resources, 1999). Eurasian watermilfoil was believed to have been introduced to the eastern United States around the 1940s, but it is possible that it may have arrived as early as the late 1800s. The first known herbarium milfoil specimen in Washington was collected from Lake Meridian near Seattle in 1965 (Washington State Department of Ecology, 2002). Eurasian watermilfoil has been spreading throughout Liberty Lakes’ perimeter since it was first discovered in 1995. Removal was controlled by divers until 1997, when the infestation became to great to handle, then Aqua-Kleen® Granular 2,4-D became the primary treatment. Each spring, aquatic weed diving surveys are conducted by Clearwater Scuba, L.L.C. and the LLSWD to evaluate potential growth and effective treatment. 2,4-D treatments have occurred since 1998 in northern and southern sections of the lake where the infestation remains in the shallow shoreline areas of approximately 1 to 3 meters in depth. More recently, the Liberty Lake Sewer and Water District has received grant funding for the Liberty Lake Milfoil Management Implementation Project from Washington Department of Ecology’s Aquatic Weed Management Fund for the fiscal year of 2004. Up to $75,000 is being offered to the Liberty Lake Sewer and Water District to cover 75 percent of the eligible project costs for the Liberty Lake Milfoil Management Implementation Project for the next 5 years. The project to be funded is implementation of the Aquatic Weed Management Plan that was drafted and funded in October 2003. It is the intent of the Liberty Lake Milfoil Management Implementation Project to implement the management strategy outlined in the plan. For more information, please contact BiJay Adams at 922-5443 ext. 30. The full text of the Liberty Lake Integrated Aquatic Weed
Management Plan is available at this site listed under the
MANAGEMENT PLAN
section of this page. It is in Adobe Acrobat Reader (PDF)
format. If you need to download Adobe Acrobat, please visit
Public
education is an important element in the control of aquatic nuisance plants.
Signs have been developed by DOE to bring attention to the Eurasian watermilfoil
infestation in lakes and to show fishermen and other lake users how to avoid
transporting aquatic plants from one lake to another. These signs have been
installed at the public boat launch at Liberty
The Sewer and Water District recognizes that the effective management will be an on-going concern and will require a long-term commitment. The Liberty Lake Sewer and Water District is willing to fund the follow-up activities necessary to ensure continued milfoil eradication and management. Monitoring of the plant community and beneficial uses such as fishing, boating, and swimming needs to be continued.
Click to enlarge the photos
SURVEYS, HARVESTS, AND TREATMENTS Click the links below the view the maps
Liberty Lake Integrated Aquatic Weed Management Plan updated on February 24, 2004 also on the DOE website at: http://www.ecy.wa.gov/programs/wq/links/plants.html
2004 Milfoil Management Report 2005 Milfoil Management Report 2006 Milfoil Management Report __________________________________________________ Under the Milfoil Management Implementation grant, an updated bathymetric (depth contour) map was produced for Liberty Lake in the summer of 2004. To view this report Click the link below. 2004 Bathymetry Mapping Project __________________________________________________
For more information about Eurasian watermilfoil (Myriophyllum spicatum), please check out the links listed below. http://www.ecy.wa.gov/programs/wq/plants/weeds/milfoil.html http://www.ecy.wa.gov/programs/wq/plants/plantid2/index.html http://www.ecy.wa.gov/programs/wq/plants/grants/fy2004.html http://www.tristatecouncil.org/pages/milfoil.htm http://www.ecy.wa.gov/programs/wq/pesticides/final_pesticide_permits/noxious/noxious_index.html
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