October 31, 2021 Wayland Surface Water Quality Committee (WSWQC) c/o Thomas Largy 59 Moore Road Wayland, MA 01778 thomas.largy@verizon.net Re:
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2021 Summary Report Water Chestnut Harvesting and Milfoil Coverage Report, Heard Pond, Wayland, MA
Dear Committee Members, In accordance with our contract, for the removal of Water Chestnut (Trapa natans) and monitoring of Eurasian Milfoil (Myriophyllum spicatum) in Heard Pond, we are pleased to provide this summary report of the 2021 management program. This report provides information on all aspects of this project including surveys, harvesting data, and ArcGIS mapping. Pre- Management Survey On July 13 and 14, 2021, a vegetation survey was conducted by Tom Largy from The Wayland Surface Water Quality Committee (WSWQC), to assess the abundance and distribution of all aquatic plant species within Heard Pond. This survey was conducted utilizing visual observation in an outboard boat, beginning around the perimeter littoral zone leading to the open water space. It was noted that the water level was 3 to 4 feet higher than norm and rosettes averaged 4-8 inches in diameter. Dense Milfoil coverage was not observed on the surface creating a canopy as observed in the past couple of years. Water Chestnut rosettes stood out, in contrast to many submerged Water Lily plants, some bearing nutlets. Clusters of Rosettes within the Lily Pads.
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Tom’s coverage and density notes; ‘There were quite a few clusters of WC rosettes along Pelham Island Road, with some bearing seeds that were near maturity. To the right of the launch site, there were sporadic WCs in the lily pad and adjoining open water areas. However, there were many dense clusters of WCs in the West cove area above the peninsula, more than I've seen in the pond in years (photo above, page 1). A lot of this area is normally very shallow and thick with lily pads, making it difficult to get a boat in and very likely resulting in a non-harvest in some recent years. This area should be harvested very soon before the pond water level goes down. The South cove area had sporadic WCs on the surface. I spotted some submersed plants, but since I have to be right on top of them to see them, it's difficult to know whether there are a number of plants still coming up. Not so many plants in the open water areas, although some clusters closer to the Western shore.’ Hand Harvest Based on the distribution of water chestnut found in the vegetation survey, SOLitude was requested to begin hand removal operations immediately. The initial hand harvesting service commenced on July 19th and concluded on July 28th. On July 19th the crews covered the east to west shorelines removing 1274 plants, broken down as follows. ▪ ▪ ▪ ▪
West side of pond - 1,020 Boat ramp to eastern shoreline 155 Eastern side of pond - 34 Eastern side of south cove- 65
On July 28th the crews returned to complete the initial sweep removing 215 plants, broken down below. ▪ ▪
West Side open water - 175 plants South Cove - 40 plants
On August 13th Tom visited the Pond to observe water chestnut growth status and report interim observations, ‘Jeff, a follow-up handpulling effort on Water Chestnuts at Heard Pond should be started as soon as possible, since some plants that were missed or too immature or submerged to be seen are now visible on the pond surface. It appears that some of these plants are near maturity and will soon be dropping seeds. I noted plants along the lily pad areas near Pelham Island Road and in the open areas near the launch site, (photo to right). I did not survey, the hotspot South Cove
August 13th observation of rosettes within lilies
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area, or the West Cove, but all pond perimeter and open water areas should be swept. The water level in the pond has subsided to seasonal norms.’. The crew conducted a sweep on August 17th and a final sweep on September 3rd collecting an additional 17 plants throughout the Pond. Tom conducted the final inspection / survey on September 5th noting, ‘Jeff, I inspected the South Cove area of Heard Pond a few days ago. I spotted only one small Water Chestnut plant, so it looks as if the harvest effort for the 2021 season was excellent.’ There was no observed change to the Milfoil distribution and density compared to the July observations. 2021 Chronology of Hand-Harvesting Events Please refer to Table 1 for a complete chronology of the 2021 management program harvesting events. Between 7/19-9/3/21 accumulative 6 days hand harvesting were completed. In sum, the harvesting effort yielded 1,506 Water Chestnut plants. Table 1: 2021 Hand-Harvesting Activities on Heard Pond, Wayland MA Date 7/13-14 7/19 7/28 8/17 9/3 9/5 Total
# of Plants Water Chestnut & Milfoil Survey, WSWQC 1274 boat ramp west and east sides 215, west side open water and South Cove 5, sweep of pond 12, final sweep of pond & Solitude inspection WSWQC inspection 1,506 plants collected
Data Analysis The total 2021 plant count, 1506, shows an approximate 13% increase in plant numbers from the 2020 harvesting year in which 1,307 plants were collected. Nutlet, seed bed appears to be trending down. Please refer to Figure 4 for a bar graph representing the number of Water Chestnut plants collected from 2009-2021. Figure 5 below, represents a summary of the total pounds of Water Chestnut collected from 2003-2008. These figures were separated due to the management method, with mechanical services used from 20032008 and primarily hand pulling efforts utilized from 2009-2020 (2009 was a dual effort, mechanical and hand removal methods).
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Conclusions In sum, the 2021 hand harvesting event totaled 6 cumulative days and removed 1,506 Water Chestnut plants. A consequence of the diminishing coverage, it has become increasing difficult to the eye to identifying trace rosettes within thriving coverage of the other aquatic plant species. It is anticipated that the Water Chestnut coverage and density will show a slight reduction from 2021 counts. The recommended 2022 aquatic management plan encompasses the same hand harvesting approach as 2021, with emphasis on early-stage monitoring prior to seed maturity. Please contact us if you have any questions or require additional information. Sincerely, Jeff Castellani Director of Mechanical Services