JOE'S POND REFLECTIONS: Arrowwood Spring Report on EWM

Here is the latest report on our Joe's Pond Eurasian watermilfoil (EWM) situation. Arrowwood Environmental out of Huntington, Vermont, did a recent survey which I have copied below; however, not everything reproduced well for me, so to see missing parts on the maps, etc, you can go to the Joe's Pond Association website (Arrowwood Environmental Memorandum, June 4, 2025).

MEMORANDUM

To: Joe’s Pond Association Date: 6/4/2025

From: Michael Lew-Smith, Arrowwood Environmental

Re: Eurasian Watermilfoil

In 2024, occurrences of Eurasian watermilfoil (EWM) were documented for the first time in Joe’s Pond in Danville and Cabot Vermont. In 2025, Arrowwood Environmental (AE) was retained by the Joe’s Pond Association to conduct an early season inventory of EWM in Joe’s Pond. The purpose of the survey was to identify locations of EWM to target control efforts in the summer of 2025. The field survey took place from May 26-May 28, 2025. This memorandum outlines the methods and results of that survey. AE personnel involved in the survey included Michael Lew-Smith, Eric Hagen and Jeff Parsons. Barry Cahoun from the Joe’s Pond Association assisted in the surveys as well.

Methods

In preparation for field work, the littoral zone of the pond as well as the locations of the previously mapped EWM were uploaded to mobile devices. Two different methods were employed to document the presence of EWM in the pond: visual littoral surveys and underwater SCUBA surveys. The visual survey consisted of viewing the aquatic vegetation from a boat. These surveys were conducted from the bow of a motorboat and, in the shallow northern areas of the third pond, from kayaks. From the motorboat, an approximate 30’ wide area into the lake can be observed. From a kayak, an approximate 20’ wide area can be observed. This technique appeared to be effective when water was calm and less than 4-5’

deep. EWM could be detected with this method in slightly deeper waters if it was growing near the surface.

In order to detect EWM in deeper waters, underwater SCUBA surveys were employed. Two types of SCUBA surveys were used: traditional SCUBA transects and motorboat-assisted transects. The traditional swimming transect was used in the boat launch area and consisted

of setting an compass bearing swimming multiple parallel transects until the entire boat launch area was surveyed. This area consisted of approximately 130’ X 150’. This area was targeted because of the threat of spread of EWM due to boat traffic. Each EWM location was marked by the placement of a marker buoy.

Where larger underwater transects were required, surveys were conducted by the diver being pulled behind the motorboat at low speeds. Two areas were targeted for these underwater surveys. First, the northwestern shore of the third pond was prioritized because of the presence of EWM in this area documented in 2024. Second, the shallow northern section of the third pond was also targeted. This area received a visual survey in 2024 by Vermont Lakes and Pond program staff, but much of the area has waters deeper than 5’ deep and due to limited visibility, EWM at these depths cannot be reliably detected from the surface.

During the motorboat-assisted surveys, if EWM was detected the diver would surface, signal to the boat crew to halt, and deploy a marker buoy at the approximate location of the EWM. In most cases, these occurrences consisted of a single EWM plant. In some cases, multiple EWM plants were present. Since the focus of these surveys was to document the locations of EWM, no attempt was made to conduct a thorough count of plants at these locations. Notes were made during data collection regarding approximate extent (in square feet) of the infestation. Upon completion of the SCUBA transect, the marker buoys were replaced by more permanent buoys and GPS location data was collected.

The GPS-enable mobile devices running ArcMap allowed tracking the location of both the visual and SCUBA surveys. The generalized track locations representing surveyed areas are shown below in Map 1.

Results

A total of 44 locations of EWM were documented during the visual and SCUBA surveys, as shown in Map 2 below. All but two occurrences were located in the third pond and most of these were located along the northwestern shore and the northern end of the pond. Only a few EWM plants were located near the populations that were documented and controlled in

2024. This indicates that the 2024 control efforts were largely successful in removing EWM

from those areas. In the shallow areas of the northern end of the pond, multiple EWM plants were documented. Given that this area was surveyed in 2024, it is likely that these plants have colonized these areas since that time. The multiple EWM infestations that were documented in deeper areas along both the northeastern shore and in the northern end of the pond may have been present in 2024. Since no deeper water surveys were conducted at that time, it is not possible to know when these became established or how long they have been present.

Each EWM location is listed, along with number of EWM plants and coordinates in Table 1. The only control efforts that took place during this inventory were in the boat launch area. Each of the EWM plants documented in this area were pulled to prevent EWM spread via boat traffic.

Table 1. EWM locations May 2025

Count	Eradicated	Latitude	Longitude
2	Yes	44.403603	-72.219034
1	Yes	44.403638	-72.218651
1	Yes	44.403651	-72.218933
1	Yes	44.40373	-72.218745
1	No	44.407518	-72.204022
1	No	44.40757	-72.203601
2	No	44.413573	-72.227393
1	No	44.413606	-72.226859
2	No	44.413836	-72.226913
1	No	44.413935	-72.226716
1	No	44.414488	-72.227165
1	No	44.414546	-72.227222
1	No	44.41458	-72.226796
1	No	44.415435	-72.227353
1	No	44.415985	-72.227362
Large Patch	No	44.416232	-72.227318
1	No	44.416413	-72.227992
1	No	44.416433	-72.227906
1	No	44.416493	-72.227984
2	No	44.416524	-72.227993
1	No	44.416849	-72.227391
1	No	44.417336	-72.227498
1	No	44.41813	-72.226349
1	No	44.41872	-72.224558
1	No	44.418901	-72.227537
1	No	44.418966	-72.22792
1	No	44.419014	-72.226423
1	No	44.41902	-72.226848
2	No	44.419049	-72.227018
5	No	44.41908	-72.226681
1	No	44.419133	-72.22633
1	No	44.419159	-72.227556
3	No	44.419573	-72.226315
1	No	44.419575	-72.227018
1	No	44.419605	-72.226042
1	No	44.419749	-72.224536

Count	Eradicated	Latitude	Longitude
1	No	44.420061	-72.224801
1	No	44.420091	-72.221073
1	No	44.420147	-72.22508
1	No	44.420341	-72.225997
1	No	44.420365	-72.225672
1	No	44.420384	-72.225638
3	No	44.420751	-72.225169
1	No	44.42076	-72.225049

When control efforts are undertaken on these infestations, a broader area around each of these locations should be searched for the presence of EWM. Additional visual and SCUBA surveys should be conducted in 2025 after control efforts have been completed to ensure that all EWM have been removed from the pond.