Meydenbauer, Newcastle Beach Closed to Swimmers Next Week for Milfoil Treatment

The swimming areas at and Newcastle beach parks will be closed next week as a precaution while nearby property owners apply herbicide to control invasive milfoil blooms.  

Although swimming will be off-limits at Meydenbauer Beach Park (419 98th Ave. NE) on Monday, July 18, and Newcastle Beach Park (4400 Lake Washington Blvd. SE) on Tuesday, July 19, the parks will remain open.

According to the state Department of Ecology, milfoil, which grows in dense mats near the shoreline, can drastically alter a water body's ecology and trap sediments. More information about milfoil can be found on Ecology’s website at
http://www.ecy.wa.gov/programs/wq/plants/weeds/milfoil.html.

Signs will be posted on-site regarding the 24-hour swimming area closures. For questions about the milfoil treatment, call Rick Bailey at 425-452-6031.

For more information about Bellevue Parks & Community Services, visit www.bellevuewa.gov/parks or call 425-452-6885.

-- Information from the City of Bellevue

According to the Department of Ecology page on Milfoil:

[M]ilfoil is considered to be the most problematic plant in Washington. The introduction of milfoil can drastically alter a water body's ecology. Milfoil forms very dense mats of vegetation on the surface of the water. These mats interfere with recreational activities such as swimming, fishing, water skiing, and boating. [...] The sheer mass of plants can cause flooding and the stagnant mats can create good habitat for mosquitoes. Milfoil mats can rob oxygen from the water by preventing the wind from mixing the oxygenated surface waters to deeper water. The dense mats of vegetation can also increase the sedimentation rate by trapping sediments.

Milfoil also starts spring growth sooner than native aquatic plants and can shade out these beneficial plants. When milfoil invades new territory, typically the species diversity of aquatic plants declines. While some species of waterfowl will eat milfoil, it is not considered to be a good food source. Milfoil reproduces extremely rapidly and can infest an entire lake within two years of introduction to the system. Although milfoil produces many seeds, we do not believe that these seeds are important for milfoil reproduction in Washington waters. However, milfoil is able to reproduce very successfully and rapidly through the formation of plant fragments. In the late summer and fall the plants become brittle and naturally break apart. These fragments will float to other areas, sink, and start new plants. Milfoil will also grow from fragments created by boaters or other disturbances during any time of year. A new plant can start from a tiny piece of a milfoil plant. This is why milfoil can so easily be transported from lake to lake on boat trailers or fishing gear. Once established in its new home, water currents may carry milfoil fragments and start new colonies within the same waterbody.