Lake Cochituate North Pond Milfoil Survey

August 31, 2010

Every year the Wayland Surface Water Quality Committee undertakes a survey of weeds in North Pond of Lake Cochituate during April and August. It has been one year since North Pond was treated with herbicides to manage milfoil Summary Weather – The weather was partly cloudy, 90+F, with a moderate NW breeze. Milfoil – Pioneer, single stalk Milfoil were found intermingled with Curley Leaf Pond Weed at various locations around the edge of North Pond. Milfoil Fragments – There were very few floating milfoil fragments seen. Pondweed – Curley Leaf Pondweed was the dominant weed seen in North Pond. Other Weeds – There were at least three other species of aquatic weeds seen in various locations and were tentatively identified as Eel Grass, Quillwort and Duck Weed.. Water Depth – The water level of North Pond was found to be approximately equal to the height of the top of the dam with no water passing over the dam or spillway. Water Clarity – Although no Secchi disc readings were taken, the visibility in the water column appeared to be greater than six feet. Method On Tuesday August 31, 2010 Lin Bradford and Toni Moores motored around North Pond starting at the Lin Bradford’s dock heading south, to visually assess the status of milfoil in the Pond. Since North Pond is relatively deep, the route that was taken around the pond followed 4’ – 6’ depth contour of the pond, where milfoil is most likely to be seen. Pictures of the main species of weeds were taken and a map of the Pond was marked up to indicate the locations of the species that were seen. Preliminary weed identifications were made based on the following source http://plants.ifas.ufl.edu/node/21 Results and Discussion The locations of weeds found in North Pond are shown in Figure 1. Milfoil – For the most part individual, single stem, bright green Milfoil plants were seen intermingled in colonies of Curley Leaf Pondweed as shown in Figure 2. None of the Milfoil plants had breached the surface and there were very few floating fragments seen. Other Weed Species – The dominant weed found in North Pond is Curley Leaf Pondweed aka Variable Pondweed. Three other weeds were found. One of these weeds, is identified as eel grass and was also intermingled with the Curley Leaf Pondweed as shown in Figures 3. Eel grass has long narrow ribbon like leaves except for the helical stalk that rises to the surface which bears the flower and seeds. The weed in Figure 4 was identified as Quillwort and is found growing on the bottom of the Pond at various locations indicated on Figure 1. Traces of Duck Weed as shown in Figure 6 were spotted in the southwest corner where North Pond abuts the Mass Pike. Duck Weed was much more prevalent in Middle Pond and South Pond.

Figure 1 – August 31, 2010 Weed Species in North Pond

Figure 2 – Milfoil among Curley Leaf Pondweed

Figure 3 - Eel Grass intermingled in Curley Leaf Pondweed

Figure 4 – Quillwort

Snake Brook Cove – As can be seen in Figure 5 Snake Brook Cove was covered with milfoil that had breached the surface with the exception of the channel that had been suction harvested.

Figure 5 - Milfoil in Snake Brook Cove

Figure 6 - Duck Weed