Mechanical Harvesting, Summer 2007

The Town of Wayland, through it’s Surface Water Quality Committee (SWQC), and the Dudley Pond Association (DPA) worked together to determine the best course of action for the 2007 growing season, in response the challenging conditions of milfoil growth, and limited by the ongoing test of milfoil weevils in the Pond, as described in the project Application. It was determined that mechanical harvesting of milfoil would be performed during the Summer of 2007, in two phases: 1) in support of a Town-sponsored evaluation of Water Circulators as a control method; and 2) to increase the usability of the Pond for recreational uses (fishing, swimming, etc).

In the spring of 2007, the Town of Wayland purchased three SunGo 001 Pond Circulators for an 18-month test that will evaluate the Circulators effectiveness in controlling non-native milfoil in Dudley Pond. The Circulators are intended to continually distribute oxygen through the water column and increase the oxidation rate of ammonia, thereby reportedly reducing its availability to the milfoil plants which rely on ammonia for their proliferation.

It had been recommended by the Circulator manufacturer that the milfoil within the test sites be cut and collected as to promote the effectiveness of this control measure and give the Circulators a "jump-start" advantage. The cutting and removal of vegetation around the Circulators should increase local circulation and oxygen distribution, thereby increasing the ability of the circulators, and theoretically quickening their ability to alter the water chemistry in the area. Further, the uniform cutting of plants near the Circulators and in a control area will help in the evaluation of the Circulators’ effectiveness by providing a homogeneous plant depth beneath the water surface from which plant growth measurements can be monitored.

The SWQC planned an experiment to compare the circulator areas to the control area – and the DPA agreed to use its funds to support the experiment by harvesting to create identical initial conditions in the circulator and the control areas.

Uniform cutting around the circulators and in a control area assists the evaluation of the circulators by providing starting homogeneous plant depth below the water surface. This allows plant growth measurements in circulator and control areas to be compared.

Note: during Phase 2 harvesting to improve the usability of the Pond, care was taken to avoid the areas of the Pond where Eurasian Milfoil weevils were introduced in 2006 as part of the S-319 Nonpoint Source Pollution Grant Program (see our Application for State Assistance for further details). The harvesting project was approved by the S-319 grant office in the Department of Environmental Protection, and the locations to be avoided were identified by the grant primary contractor, GeoSyntec Consultants, and the Town-appointed grant project manager.

A detailed summary of the 2007 harvesting can be found in the Quarterly Report to the Conservation Commission, Fall 2007. You can read it here, minus the photos at the end. The photos are posted separately, here [UNDER CONSTRUCTION].