List members, I wanted to pass on this response I got from the Park Board on milfoil removal strategy. I passed on Tim David's post from a few weeks ago to inquire if the strategy employed in Bald Eagle Lake was viable in our Minneapolis lakes. The City, Park Board and Watershed Districts are working together on a Water Quality Monitoring Task Force, and we're all keenly interested in innovative ideas like this to address milfoil and other water quality issues. Laura Sether Office of Mayor Rybak Standish-Ericsson From: Aplikowski, Sara A. Sent: Wednesday, July 28, 2004 2:54 PM To: Schmidt, Michael P. Subject: RE: milfoil strategy The Minneapolis Park and Recreation Board also believes that our lakes are extremely valuable resources that require sound management. The mission of the Minneapolis Park and Recreation Board is to, on behalf of all current and future citizens of the City of Minneapolis, strive to permanently preserve, protect, maintain, improve and enhance the City's parkland and recreational opportunities. The lake ecosystems in Minneapolis are incredibly complex as well. In addition, they are unique in having such highly urbanized watersheds. In the early stages of the Eurasian watermilfoil infestation, divers were used at Lake Harriet. This effort was expensive and unsuccessful. Hand pulling of the plants may be successful in controlling small infestations. However, the infestations facing our lakes are anything but small and isolated. Eurasian watermilfoil is growing aggressively in most areas of our lakes. For comparison: White Bear Lake 3 acres nuisance growth out of 600 acres (0.5%) Lake Harriet 71 acres plant growth out of 350 acres (20%) Calhoun Lake 57 acres plant growth out of 420 acres (14%) Cedar Lake 46 acres plant growth out of 170 acres (27%) The plant growth in the Chain of Lakes is, depending on the specific location, almost entirely milfoil. While hand pulling may be feasible and helpful at White Bear Lake, it is not feasible for the infestations in the Chain of Lakes. According to the Minnesota DNR, Eurasian watermilfoil has not been permanently eliminated from any lake in Minnesota by the use of herbicides or by hand pulling. The DNR does not usually allow whole lake herbicide treatments. They have tried SONAR (active ingredient fluridone) on several lakes. The DNR found that using SONAR on eutrophic lakes did more harm than good. Native species were negatively affected and in some lakes water clarity degraded. The DNR has not taken a formal position on the use of SONAR in mesotrophic lakes, feeling that it requires more study. As part of the Park Board's role as environmental steward and as part of our policy on Integrated Pest Management, herbicide applications are considered only as a last resort if at all. In the case of Eurasian watermilfoil in the Chain of Lakes (and Hiawatha and Nokomis), there are upstream sources of milfoil. And since one fragment can start a new plant, an herbicide treatment would need to be repeated every one to two years. This is analogous to the use of herbicides to control dandelions and other weeds on a lawn. Herbicides have not eradicated weed species, need to be continually applied, can create resistant strains of pests and can have undesirable effects on non-target species. SONAR is not recommended at this time because of the cost, the difficulty in obtaining DNR permission, the interconnectedness of our water bodies, the environmental implications and the general reluctance of the public to have chemicals applied to the lakes. The Park Board has involved citizens with multiple opportunities for input at many public meetings including the Clean Water Partnership and the Blue Water Commission. At this point in time, citizens seem to be in support of the harvesting efforts that occur on the Minneapolis Chain of Lakes. The Minneapolis Park and Recreation Board has also cooperated with the University of Minnesota to investigate the use of biocontrol agents in the battle against milfoil (using an EPA 319 grant). Aquatic weevils that eat Eurasian watermilfoil and burrow through the stems were released into parts of Cedar Lake, Lake of the Isles, Lake Harriet and Lake Hiawatha. Weevils have not been as successful controlling milfoil in the Chain of Lakes as they have at other lakes being studied. Fish predation is probably the cause. High sunfish densities in our lakes are likely limiting weevil populations. Mechanical harvesting is the current strategy that the Park Board is following. The harvested plants are removed for composting, which has the added benefit of removing phosphorus from the lakes. Over time, harvesting may also deplete nitrogen in the sediments. Low sediment nitrogen has been shown to limit nuisance growth of Eurasian watermilfoil in some lakes. However, our lakes are under constant pressure from urbanization and have a continual supply of nutrients from storm water. So while it may take many years to see an impact from harvesting, harvesting milfoil remains our best strategy. Sara Aplikowski Water Resources Coordinator Minneapolis Park & Recreation Board Mayor and List Members Our Lake Association of Bald Eagle Lake in Ramsey County has been actively managing lake vegetation for over 15 years. We have been one of the more progressive metro area lake associations. We have eradicated Eurasian milfoil, removed 2 million pounds of curly leaf pondweed and over 600 lbs. of phosphorous to reduce algae blooms, and now are on the road to re-establishing the native vegetation of our lake. Our learning is that the lake ecosystem is very complex and for every action in the lake there is a reaction; and that it is imperative that you develop a strategy, and take action. We first instilled in our community the understanding that the lake is a very valuable resource that must be actively managed to maintain its value. With community buy-in, our efforts went through the following stages: 1. Utilized block captains to patrol segments of the lake to identify outbreaks of Eurasian milfoil and then used targeted chemical treatments to eradicate Eurasian milfoil. 2. Once milfoil no longer controlled our lake, curlyleaf pondweed overtook our lake and became a greater nuisance than milfoil, and a major contributor to severe algae blooms in the late summers. 3. Developed a 5 year curlyleaf cutting and harvesting program that was funded by contributions from area residents, local government agencies including municipalities, counties, our Watershed District, and DNR, and local businesses. 4. Cut and harvested over 2 million lbs. of curly leaf containing over 600 lbs of phosphorous. 5. With curlyleaf removed, we have a crop of a hybrid milfoil (not Eurasian - as confirmed through DNA testing by DNR) that is a small nuisance. We anticipate that this small nuisance will be overtaken by desirable, non-nuisance, native vegetation. We conduct extensive annual aquatic vegetation surveys, take lake bottom sedimentation fertilization samples, work with our local gov't agencies on upstream improvements, and we hired a lake specialist Steve McComas from Blue Water Sciences for the last 10 years to advise us. He was very key in our understanding the dynamics of the lake ecosystem and providing us with technical guidance on leading practices. Bottom line is we have improved water clarity, substantially reduced the nuisance vegetation, and have reduced the frequency and severity of the algae blooms. It isn't easy, and we are not done, however, this resource is manageable - and your lake resources are so valuable - you must manage them. Tim David REMINDERS: 1. Think a member has violated the rules? Email the list manager at [EMAIL PROTECTED] before continuing it on the list. 2. Don't feed the troll! Ignore obvious flame-bait.
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