DEP 332-0859 Dudley Pond
2019
SWQC member Mike Lowery shows tapegrass and milfoil to children during DPA run.
Wayland Surface Water Quality Committee 2019 End of Season Report for Dudley Pond
Dudley Pond – DEP 332-0859 2019 End of Season Report
SUMMARY: PEAK YEAR FOR EURASIAN MILFOIL AND TAPEGRASS AND EXPENSE ACCOMPLISHMENTS: ............ 3 2008-2019 COST COMPARISONS & HERBICIDE TREATMENT YEARS VS NON-TREATMENT YEARS .......................... 4 2019 MILFOIL HAND-PULLING AND DASH .............................................................................................................. 5 2019 TAPE GRASS MECHANICAL HARVESTING ....................................................................................................... 6 2019 PROBLEMS, HANDICAPS, ISSUES & OPPORTUNITIES ................................................................................... 10 2019 HERBICIDE RESIDUALS TESTING ................................................................................................................... 11 2019 LONG TERM HERBICIDE MINIMIZATION PROGRESS .................................................................................... 12 2019 WATER QUALITY TESTING ........................................................................................................................... 13 2019 E. COLI TESTING AT MANSION BEACH ......................................................................................................... 17 CALENDAR 2019 COST & INVOICE RECAP ............................................................................................................. 18 2020 SEASON PLANS ............................................................................................................................................ 19 APPENDIX A - SOLITUDE YEAR END REPORT........................................................................................................ 20
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Dudley Pond – DEP 332-0859 2019 End of Season Report
SUMMARY: Peak year for Eurasian Milfoil and Tapegrass and expense Accomplishments: • • • • • •
Funding: Continued 25% shared funding with the DPA whose members care deeply about Dudley Pond and who directly enjoy its benefits. DPA gift funds saved the day - $45,000 transferred for both milfoil and tapegrass. $15,000 from 2019 reimbursements. Continued consensus for limiting herbicide with goals and programs to minimize its use. Completed annual testing for detection of herbicide residuals in raw water from the Happy Hollow wells. Continued Water Quality sampling & analysis 3x in 3 locations Second, much larger mechanical harvest of tapegrass
Yearend status: • Milfoil well controlled. Tapegrass barely under control and expanding, pond in good trophic state. • 3-year guarantee for milfoil control in the treated areas. NO milfoil was detected anywhere in the pond at year end
Sunset at Mansion Beach (photo credit: Sheila Carel) Wayland Surface Water Quality Committee
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2008-2019 Cost comparisons & Herbicide Treatment Years vs non-treatment years
After the whole lake treatment in 2008, two years later a spot treatment was done in 2010. The next spot treatment was three years later in 2013 – achieving a goal of lengthening the periods between herbicide treatments. In 2016, three years later, we did an area-specific treatment with fluridone. The 2016 treatment reduced the need for hand pulling in 2017, but milfoil came back strong in 2018. A pattern of spot treatment being needed every three years has emerged, with the 2019 treatment with ProcellaCOR. We hope that the new herbicide ProcellaCOR will further lengthen the interval between herbicide applications. Mechanical Harvesting of tapegrass was necessary for the first time in 2018. Over
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 MILFOIL HAND-PULLING and DASH Milfoil Hand Pulling – start and end dates 2011 - 2019 Hand Pull started Hand Pull ended #Days in season
2011 5/5
2012 4/24
2013 4/15
2014 5/27*
2015 5/4
2016 n/a
2017 8/17
2018 5/11
2019 6/2
9/11
11/6
10/10
10/6
10/6
n/a
10/23
10/16
6/5
130
197
179
133
156
n/a
67
158
4
Only diver-assisted suction harvesting (DASH) was used in 2019. We focused on an area between the Mansion and Chateau Arms which had grown quickly and was near the top and being cut by props on boats going between these arms. We did four days of DASH in the small highlighted areas on this map (not the brown highlighted areas).
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 TAPE GRASS MECHANICAL HARVESTING Vallisneria Americana, aka tape grass, or eel grass had become prominent in some areas by the end of 2015. Tapegrass has taken over beds where milfoil used to predominate and is now just as serious a problem. First spotted in 2010 South of the peninsula in the Chateau arm, it has spread into areas below and forms thick mats making boating problematic. It can spread by seeds but mostly through its rhizomes – runners in the sediments. It has spread into new areas, interferes with milfoil hand pulling, is a hazard to swimmers, and interferes with recreational uses. One swimmer and her dog became entangled this season.
In 2017 tape grass was suppressed by the fluridone treatment to the extent it did not require mechanical controls. But in 2018 was mechanically harvested for four days 2019 tape grass mechanical harvesting was in two contracts: • 6 days $9,600 + $1,500 mobilization in/out • 8 days $12,800
We began our harvest too late in the season. The tape grass got an early start this year. In order to avoid making milfoil fragments when cutting, we planned tape grass harvesting after the milfoil treatment had become effective. The late start in mechanical harvesting was caused by: 1. Massachusetts delays in DEP/DCR permitting of ProcellaCOR 2. The necessity to vet the new herbicide before Conservation, Health, Recreation, and the Selectmen. 3. Conservation’s requirement to do the herbicide treatment in two stages with time gaps between them. 4. Mechanical equipment delays totaled five days of downtime. The contractor worked one weekend day.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
1 - Fall Tape Grass - showing seed pods (120 Lakeshore Drive)
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Dudley Pond – DEP 332-0859 2019 End of Season Report
SWQC contracted with Solitude for tape grass mechanical harvesting in these areas:–
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Dudley Pond – DEP 332-0859 2019 End of Season Report
Harvested tape grass was removed by the DPW on four different dates, usually requiring 3 small dump truck loads on each date. We estimate 800 cubic feet of tape grass was removed. The removed material was remarkably free of milfoil – and other non-target species.
Wayland Surface Water Quality Committee
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 PROBLEMS, HANDICAPS, ISSUES & OPPORTUNITIES •
We had limited success at the end of the season controlling Canada Goose waste. Dog waste seems under control thanks to refuse bins installed by the DPW
•
New procedures were in place for the acceptance and use of gift funds. Elizabeth Doucette helped us through this transition.
•
SWQC performed extensive water sampling to determine if dissolved oxygen levels would drop due to ProcellaCOR treatments. Hopefully this testing has given enough reason to be more confident and fewer samples will be required in the future.
•
Using a new herbicide caused additional concerns and required more education of other committees and the public than normal.
•
Michael Lowery resigned from SWQC in 2019 after an incident where he believed the Selectmen had maligned his reputation by listing his name on a conflict of interest agenda item based on his being an abutter to Dudley Pond.
•
Continued difficulty of matching natures whims and the effects of treatment to a municipal budgeting process which is half in one fiscal year and half in another, and end of year unspent budget is returned to the General Fund. SWQC hopes to overcome this by using a financial warrant as suggested by Town Administrator Louise Miller.
Wayland Surface Water Quality Committee
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 HERBICIDE RESIDUALS TESTING Neither fluridone, triclopyr, nor florpyrauxifen-benzyl were detected in Happy Hollow raw water samples. Since the first use of fluridone in 2008, SWQC has, as required by its order of conditions, taken raw water samples from the Happy Hollow wells and tested for herbicide residuals. On 10/21/2019, SWQC took samples of raw water from the Happy Hollow wells and sent them to SePRO for testing. No detectable concentrations were found. Results were reported to the Water Department, Board of Health, and Conservation. We will continue this testing in 2020.
Happy Hollow Well Approx. 3300’ from closest point on Dudley Pond, but connected by Dudley Brook.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 LONG TERM HERBICIDE MINIMIZATION PROGRESS SWQC’s long-term goal is to continue to reduce the viable milfoil root mass through hand-pulling and spot treatment when and where necessary. We have made good progress away from a boom-bust cycle toward year to year management and herbicide minimization. •
Two years between the full lake fluridone treatment in 2008 and the first triclopyr spot treatment in 2010.
•
Three years between the 2010 triclopyr spot treatment and the 2013 triclopyr spot treatment.
•
Three years between the 2013 triclopyr spot treatment and the 2016 area-specific fluridone treatment.
•
Three years between the 2016 triclopyr spot treatment and the 2019 area-specific treatment with ProcellaCOR (Florpyrauxifen-benzyl)
. As in prior years herbicide treatment was contained in Dudley Pond by sandbagging the outlet until herbicide concentrations had substantially dissipated. Thanks to the DPW for helping make the sandbags. Sandbags were only removed after herbicide was below detectable levels.
Part of herbicide minimization are efforts to reduce nutrients flowing into Dudley Pond by septic regulations, education, and improvement of stormwater handling. An MS4 goal is an inventory of our outfalls and identification of the areas drained by them using the Massachusetts watershed-based planning tool, developed by GeoSyntec for MA DEP: http://prj.geosyntec.com/MassDEPWBP
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 WATER QUALITY TESTING Begun in 2011, in 2019 the SWQC did three rounds of water quality sampling – where samples were taken at 3 points. Samples were taken in April, August, and November.
Using a Secchi disk and YSI meter, barometric pressure, pH, ORP, Dissolved Oxygen, Temperature were taken at three depths per point. Water samples were analyzed by an analytical lab for total P, soluble P, Ammonia, Nitrate/Nitrite, Nitrogen, and Chlorophyll a. Using the Carlson Trophic index, Dudley Pond has been on the margin between mesotrophic and eutrophic since 1978. Spring 2019 Summary: • •
•
On March 27, 2019 water quality data was gathered at three sample points and at three depths at each sample point. Water quality parameters such as pH, oxidation-reduction potential (ORP), dissolved oxygen (DO), dissolved oxygen % saturation, and temperature were measured at three depths at each of the three sample points by SWQC members using a YSI Multimeter. Water and Secchi depths were measured at each of the three sample points. Samples were gathered by SWQC members and analyzed by Nashoba Analytical LLC.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
• • • •
On March 27, 2019, based on somewhat uniform parameter values top to bottom, the Pond was mixed and therefore it is assumed that the sampling occurred near the time of the spring turnover (water column mixing). The Secchi depth, which is a measure of visibility in the water column, was determined to be eleven feet, two inches. This Secchi depth is certainly not the best depth that has been measured nor was it the worst as can be seen from the table below. Chlorophyll-a concentrations, a measure of the algae concentration, was relatively good compared to values obtained over the past eight years. As Dudley Pond is primarily used for recreational purposes a Trophic State Index (TSI) less than 50 is tolerable and less than 40 is very good. The TSI on March 27, 2019, for the three sample points, ranged from approximately 33 to 43 indicating that the Dudley Pond TSI was between oligotrophic and mesotrophic range, which is good.
Date April 4, 2011 March 18, 2012 March 24, 2013 April 2, 2014 April 21, 2015 March 23, 2016 March 26, 2017 March 29, 2018 March 27, 2019
TSI 31 – 49 39 – 47 35 – 43 39 – 54 41 – 46 35 – 40 21 – 41 22 – 36 33-43
Chlorophyll a 2.72 – 3.99 ppb 1.98 – 4.62 ppb 1.39 – 4.46 ppb 2.24 – 5 ppb 0.74 – 4.53 ppb 0.89 – 5.13 ppb 0.59 – 1.1 ppb ND – 1 ppb 0.9ppb – 2.3ppb
Secchi Depth 12’ 1” 12’ 6” 14’ 4” 9’2” 11’ 6” 15’ 12’ 19’ 11’2”
Total Phosphorus 10 – 40 ppb 10 – 20 ppb Non-detect 10 – 20 ppb Non-detect Non-detect 0 – 10 ppb ND MD
Summer 2019 Summary: • •
• • •
•
•
On August 7, 2019 water quality data was gathered at three depths at three sample points. Water quality parameters such as, pH, oxidation-reduction potential (ORP), dissolved oxygen (DO), dissolved oxygen % saturation, and temperature were measured at three depths at each of the three sample points by SWQC members using a YSI Multimeter. Water and Secchi depths were measured at each of the three sample points. Samples were gathered by SWQC members and analyzed by Nashoba Analytical LLC. As Dudley Pond is primarily used for recreational purposes, a Trophic State Index (TSI) less than 50 is tolerable and less than 40 is great. A TSI range of 35 – 55 for August 7, 2019 is not particularly good. The TSI range, which is based on a combination of Secchi Depth, Chlorophyll a and Total Phosphorus concentrations, was high (not good) despite an unusually good Secchi Depth (transparency) on August 7, 2019. The moderately high TSI was because of elevated concentrations of Total Phosphorus. High concentrations of Total Phosphorus and a high TSI range are indicators of poor water quality. A thermocline (layering caused by temperature differences) on August 7, 2019 was found at approximately 12 feet, which is typical for the summer samplings; however, with the Secchi depth of 12’ 7” on August 7, 2019, there was probably limited photosynthesis below the thermocline. An elevated ORP, no odor and marginally aerobic conditions in the deep hole (> 20 feet) at Sample Point 25 are thought to be the result of limited photosynthesis below the thermocline. There was no measurable Total Kjeldahl Nitrogen found at any of the sample points on August 7, 2019, which is unusual for a summer sampling. The reason for this is unknown.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
•
The table below presents parameters making up the TSI range as well as the TSI range resulting from August samplings. Lower numbers for TSI, Chlorophyll a and Total Phosphorus indicate better water quality. High numbers for Secchi depths also indicate better quality water.
Date
TSI *
Chlorophyll a * range 7.0 ppb 4.41 – 6.3 ppb 2.9 – 17.29 ppb
August 24, 1981 49 – 54 Sept. 11, 2011 44 – 48 August 5, 2012 48 – 52 4.65 – 13.03 ppb August 5, 2013 43 – 48 7.48 – 10.83 ppb August 3, 2014 47 – 53 1.19 – 2.54 ppb August 3, 2016 30 – 44 1.19 – 3.86 ppb August 1, 2017 30 – 46 1.2 – 3.1 ppb July 31, 2018 31 – 39 MD – 3.4 ppb August 7, 2019 35-55 * Above the thermocline which is usually at about 12 feet **Contaminated sample
Secchi Depth 2.1’ 9.83’ 6.75’ 10.75’ 8.24’ 9.8’ 9’ 14’1” 12’ 7”
Total Phosphorus* range 30 ppb ND ND ND – 20 ppb ** ND 10 – 20 ppb ND – 20 ppb ND – 20 ppb 20-40 ppb
Fall 2019 Summary: Table 1 – Key Dudley Pond Water Quality Parameters Date
TSI
Chlorophyll a ppb
Nov 18, 2007 Nov 13, 2011 Nov 11, 2012 Nov 15, 2013 Nov 12, 2014 Nov 16, 2015 Nov 14, 2016 Nov 9, 2017 Nov 8, 2018
42 – 44 42 – 46 49 – 51 47 – 48 26 – 43 40 – 45 20 – 42 20 – 44
-
2.6 – 6.6 2.2 – 4.6 4.24 – 9.79 4 – 6.3 0.39 – 3.29 ND 0.42 – 1.0 ND – 1.0
Secchi Depth meters 2.85 3.4 3.4 2.12 2.73 4.39 4 3.7 4.75
Total Phosphorus ppb ND – 10 ND ND ND ND ND – 20 ND – 20 ND – 30
ND = Non-Detect
Below is a graphical representation of the water clarity, chlorophyll and phosphorus combined to show the ‘trophic’ state of Dudley Pond – the chart uses November 2019 data. Wayland Surface Water Quality Committee
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Dudley Pond – DEP 332-0859 2019 End of Season Report
[
This is a very positive result which derives from the state’s mandated reductions in phosphorus, the replacement of older septic systems over many years, and stormwater management within the relatively small watershed of Dudley Pond. Dudley Pond is still classified on MA 303(d) list as a category 5 (most impaired) due to high nutrient levels. The base data on which this classification is based is quite old. The eight years of SWQC water quality data for Dudley Pond may allow its reclassification on the MA 33D list to EPA.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2019 E. coli TESTING at MANSION BEACH HISTORY: After a leaking septic system was noted near the pond in 2011, in cooperation with the Health Department, SWQC organized periodic testing at Mansion Beach for E. coli. Year 2012 2013 2014 2015 2016 2017 2018
# of Exceedances 0 1 2 1 1 4 1
Average CFU/100ml 25 66 188 99 102 146 110
2019
1
137
DPA volunteers Ella and Allison LaClaire took samples at Mansion Beach for analysis by the Health Department’s state-certified lab. Samples are collected and analyzed per state protocols for beaches.
The beach was closed on 7/3/2019 Exceedances were related to waterfowl on Mansion Beach and samples taken a few days after a rain event. A harassment campaign using sound was effective at the end of the season to keep the geese away most of the time.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
Calendar 2019 COST & INVOICE RECAP
The Dudley Pond Association reimburses 25% of town costs related to weed management in Dudley Pond.
Wayland Surface Water Quality Committee
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Dudley Pond – DEP 332-0859 2019 End of Season Report
2020 SEASON PLANS Well Sampling: We will continue annual spring tests of water from the Happy Hollow wells for fluridone, triclopyr, and florpyrauxifen-benzyl. If an herbicide has not been used in five years, sampling for that herbicide will be discontinued. Samples will be analyzed by SePRO, and copies of test reports will be provided to the Conservation Commission, the DPW Water Division, and Board of Health. Hand-pulling: Hand-pulling will continue likely starting in July 2020. Mechanical cutting: Tapegrass will be cut back if it begins to obstruct recreational uses or endanger swimmers. Mechanical harvesting is costly, and its timing is difficult to get right because we cannot cut deeper than our OOC allows, but we want to cut before seed pods are formed and before the spiral stems can entangle boats, swimmers, and personal watercraft. We will be investigating the cost of small mechanical harvesters to be stored and managed by the DPW Herbicide: We do not expect to use herbicide in 2020. Water Quality Testing: We will continue a 3x per season water quality sampling and testing plans begun in Dudley Pond in 2011. Mansion Beach E. coli monitoring – We will continue to collaborate with the Health Department to monitor E. coli levels at Mansion beach weekly during the swim season. Stormwater – New MS4 permit requirements began to effect Wayland in July 2019. SWQC will collaborate with Conservation and DPW on the Stormwater Task Force to inspect and evaluate the condition of manholes, improve mapping of catch basins, and outfalls and perform water quality analysis. Consider purchase of small mechanical harvester. We hope to evaluate the viability and economics of purchasing a small mechanical harvester for use in Dudley Pond and other town water bodies. It is possible such a device could skim algae in spring, harvest milfoil during the summer, and harvest tape grass during the late summer and fall.
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Dudley Pond – DEP 332-0859 2019 End of Season Report
APPENDIX A - Solitude Year End Report The following pages are the 2019 Year End Dudley Pond report received from Solitude
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Annual Report 2019 Aquatic Management Program Dudley Pond Wayland, MA
Prepared by:
SŌLitude Lake Management 590 Lake Street Shrewsbury, MA 01545
Prepared for:
Wayland Surface Water Quality Committee c/o Mike Lowery
Submitted on:
November 15, 2019
Introduction Management and monitoring of vegetation in Dudley Pond has been conducted for over two decades to assess and manage non-native, invasive species, primarily Eurasian watermilfoil (Myriophyllum spicatum). Monitoring assists in tracking invasive species abundance and distribution; assess changes in the native plant composition; determine effectiveness of invasive control efforts; and guides future management goals and activities. Previous in-lake management has included spot-treatment and whole-lake Sonar (fluridone) herbicide treatments, as well as spot-treatments with Renovate (triclopyr) herbicide. Nonchemical control strategies including volunteer weed-watching, hand-pulling and diver assisted suction-harvesting (DASH) have also been utilized significantly throughout the years as part of the integrated management plan. Registered with the US EPA in 2018 and MA DEP in 2019, ProcellaCOR EC (florpyrauxifen-benzyl) herbicide is a new milfoil-selective, systemic technology from SePRO (manufacturer of Sonar and Renovate products). With a reduced-risk label from the EPA, ProcellaCOR has an incredibly favorable toxicology profile with minimal water-use restrictions, thus making it an excellent choice for spot-treatments this year at Dudley Pond. The following report documents the management activities conducted in 2019 and provides recommendations for future management efforts. A chronology of this year’s management events is as follows: 2019 Program Chronology Early summer vegetation survey .............................................................................. 06/11/19 Wayland Conservation Commission amendment hearing .................................. 06/06/19 MA DEP License to Apply Chemicals issued........................................................... 06/20/19 Amended OOC issued .............................................................................................. 07/11/19 Area 4 ProcellaCOR treatment ................................................................................ 07/30/19 Area 1 ProcellaCOR treatment ................................................................................ 08/13/19 Post-management vegetation survey .................................................................... 10/01/19 ProcellaCOR FasTEST monitoring ............................................................. August-September Milfoil monitoring by volunteers ........................................................................ April-October
590 Lake Street, Shrewsbury, MA 01545 | 508-885-0101 | SOLITUDELAKEMANAGEMENT.COM
Page 2
Early Summer Vegetation Survey On June 10, a SŌLitude biologist conducted a thorough inspection of the entire littoral zone of Dudley Pond to assess invasive species growth, specifically Eurasian watermilfoil and determine management areas for the 2019 season, in anticipation of a ProcellaCOR herbicide treatment. As anticipated based on the monitoring done by the Wayland Surface Water Quality Committee (WSWQC) volunteers, there were varying densities of Eurasian milfoil observed throughout the littoral zone. Most of the densest growth was located along the northwestern and southeastern shorelines; however varying densities of Eurasian milfoil were present throughout almost the entire littoral zone. Growth along the southeastern shoreline extended throughout the entire cove but was less dense in the northern half of the cove. The growth along the northwestern shoreline extended from approximately where Castlegate Rd meets Lakeshore Dr, following the shoreline clockwise approximately three quarters of the way to the outlet; the growth also extended from the northern shoreline to the Dudley Rd peninsula. A map of the early season vegetation growth conditions is attached. Curlyleaf pondweed (Potamogeton crispus) was also present in trace to moderate densities in all areas where Eurasian milfoil was observed. Treatment Program In coordination with Mike Lowery of the WSWQC, the existing Order of Conditions and Chapter 194 Permit for Dudley Pond were amended to include use of ProcellaCOR EC herbicide. To remain in compliance with the newly amended conditions, pre-treatment water quality monitoring (temperature, dissolved oxygen and pH) was conducted by both SŌLitude and WSWQC immediately prior to the treatment of Area 4 on July 30. Both parties conducted the monitoring together for comparison of results to allow WSWQC to proceed with the additional monitoring requirements on their own. Following the pre-treatment water quality monitoring, the initial ProcellaCOR EC herbicide treatment was conducted to the 12.6 acres of Area 4. Treatment was performed using a 20-foot jonboat equipped with a calibrated pump system for subsurface application of the liquid herbicide. To ensure even application within the designated treatment areas and to provide real-time tracking of the treatment boat, an onboard GPS unit was utilized. Weather conditions the day of treatment were good, with sunny, clear skies, high temperatures in the upper 80s and variable winds. At no time during the treatment were any non-target impacts to other aquatic organisms or wildlife either observed or reported. Following the pre-treatment monitoring, all results from SŌLitude and WSWQC were submitted to the Wayland Conservation Commission Agent for approval for WSWQC alone to continue the required monitoring for the remainder of the treatment program, which was granted. As such, WSWQC conducted the same water quality monitoring efforts at 2, 7, and 20 days after treatment (DAT) in accordance with the permit special conditions. Prior to the treatment of Area 1 on August 13, WSWQC again conducted the required pretreatment water quality monitoring (temperature, dissolved oxygen, pH) for that treatment area. The 30.2 acres within Area 1 were also treated utilizing ProcellaCOR EC herbicide; treatment this time was conducted via airboat, also equipped with an onboard calibrated pump system to allow for subsurface application of the liquid herbicide. Again, an onboard GPS unit was used to ensure even application within the designated treatment areas and to provide real time tracking of the treatment boat. A map showing both of the treatment areas is attached.
590 Lake Street, Shrewsbury, MA 01545 | 508-885-0101 | SOLITUDELAKEMANAGEMENT.COM
Page 3 Weather conditions during the second ProcellaCOR application were also good, with sunny, clear skies, temperatures in the 80s and moderate winds. At no time during this treatment were any non-target impacts to aquatic organisms or wildlife either observed or reported. As with the initial treatment, WSWQC conducted the required post-treatment water quality monitoring at 2, 7, and 20 DAT for this treatment and area also. A map of all water quality sample locations is attached. ProcellaCOR Herbicide Residue Sampling Similar to prior herbicide treatments at Dudley Pond, post-treatment herbicide residue sampling was conducted. A summary of the results are in the table below and copies of the results from the SePRO Laboratory are attached. Date 08/01/19 08/06/19 08/15/19 08/20/19 09/03/19 10/21/19
Location Area 4 – point 3 Area 1 – point 9 Area 1 – point 9 Area 1 – point 9 Area 1 – point 9 Happy Hollow Well
Result (ppb) <1 <1 <1 <1 <1 <1
Post-Treatment Survey A survey was conducted on October 1, 2019 by a SŌLitude biologist accompanied by Allison LaClaire, a primary hand-pulling diver who lives on Dudley Pond. The entire pond was toured, with additional focus spent surveying the treatment areas to assess the treatment’s impacts. At the time of the survey, a SŌLitude harvester was actively harvesting nuisance tapegrass and Aquatic Vision also had a crew harvesting tapegrass in other areas as well. Within both treatment areas, there were no viable milfoil stems observed. Additionally, all other species present, primarily tapegrass, were healthy and not impacted by either ProcellaCOR application. Native species other than tapegrass were observed at lesser densities as tapegrass was the dominating species densely covering almost all areas of the littoral zone, both within and outside of the treatment areas. Additionally, no viable milfoil stems were observed outside of either treatment area. Minimal control outside of the treatment areas was anticipated due to the shorter required contact time of ProcellaCOR. A map showing the distribution of tapegrass is attached. Summary and Ongoing Management Recommendations Although the last whole lake Sonar herbicide treatment at Dudley Pond proved to be effective for 2-3 seasons following treatment, switching to ProcellaCOR EC herbicide this year allowed for use of less herbicide overall and only a single application per treatment area for effective control of Eurasian watermilfoil growth. Both treatment areas were plagued with relatively dense milfoil growth prior to treatment and had all native species remaining following treatment. As not all of the milfoil infestation in Dudley Pond was actively treated, but no viable growth was observed during the post-treatment survey, it is anticipated that regrowth will appear in the nontreated areas before those that were treated. As such, it is recommended that annual or biannual aquatic vegetations surveys are conducted to appropriately monitor and track any regrowth that occurs throughout the pond. Additionally, these survey efforts can be used to guide any hand-pulling or suction harvesting efforts that may need to be coordinated to manage any regrowth.
590 Lake Street, Shrewsbury, MA 01545 | 508-885-0101 | SOLITUDELAKEMANAGEMENT.COM
Page 4 As tapegrass growth became a mounting issue during the second half of the 2019 season, it is recommended that a larger scale harvesting effort is undertaken or the WSWQC considers other management options to maintain open water conditions for habitat and recreational uses. If other consulting services are desired, please do not hesitate to reach out for additional recommendations as we can provide those to the WSWQC as well.
590 Lake Street, Shrewsbury, MA 01545 | 508-885-0101 | SOLITUDELAKEMANAGEMENT.COM
June 2019 Invasive Aquatic Species Distribution 888.480.5253 solitudelakemanagement.com
Legend Eurasian Watermilfoil Trace to sparse Sparse to moderate Dense Curly-leaf Pondweed Trace to Sparse Sparse to Moderate
Dudley Pond Wayland, MA Middlesex County 42.3301° N, 71.3728° W
Dudley Pond 0
540 1:6,000
¯
1,080 Feet
Map Date: 11/05/19 Prepared by: KS Office: Shrewsbury, MA
Recommended ProcellaCOR Treatment Areas 888.480.5253 solitudelakemanagement.com
Area 2: 18.8ac.
Area 1: 30.2ac.
Area 3: 16.6ac.
Area 4: 12.6ac.
Legend Eurasian watermilfoil (78.2 ac) Sparse Moderate Dense
Dudley Pond Wayland, MA Middlesex County 42.3301° N, 71.3728° W
Dudley Pond 0
520 1:6,000
¯
1,040 Feet
Map Date: 11/05/19 Prepared by: KS Office: Shrewsbury, MA
ProcellaCOR Treatment Areas 888.480.5253 solitudelakemanagement.com
Area 1: 30.2ac.
Area 4: 12.6ac.
Legend Moderate Dense
Dudley Pond Wayland, MA Middlesex County 42.3301° N, 71.3728° W
Dudley Pond 0
530 1:6,000
¯
1,060 Feet
Map Date: 11/05/19 Prepared by: KS Office: Shrewsbury, MA
Pre/Post-Treatment Sample Points 888.480.5253 solitudelakemanagement.com
#
10
# #
11
Area 2: 18.8ac.
9
Area 1: 30.2ac.
# #
8
#
7
12
Area 3: 16.6ac.
#
6
#
5
#
#
3
2
Area 4: 12.6ac.
#
1
#
4
Legend #
Sample points
Eurasian watermilfoil (42.8 ac) Moderate Dense
Dudley Pond Wayland, MA Middlesex County 42.3301° N, 71.3728° W
Dudley Pond 0
550 1:6,000
¯
1,100 Feet
Map Date: 11/05/19 Prepared by: KS Office: Shrewsbury, MA