Dudley Pond 2010 Report ACT complete

November 3, 2010

Wayland Surface Water Quality Committee Attn: Michael P. Lowery, Project Manager Wayland Town Building

41 Cochituate Road Wayland, MA 01778‐2614

Re: Year‐End Report for 2010 Renovate OTF Herbicide Treatment Program at Dudley Pond

Dear Mr. Lowery:

Please accept the following as our year‐end report for the Renovate OTF herbicide spot‐treatment program performed at Dudley Pond in 2010 for control of Eurasian watermilfoil (Myriophyllum spicatum). The treatment was performed in accordance with the product label directions, conditions of the Order of Conditions and Chapter 194 Permit for Dudley Pond (DEP 332‐698) issued by the Wayland Conservation Commission, and the License to Apply Chemicals (No. 10207) issued by MA DEP. The following report details the treatment program and monitoring tasks conducted by Aquatic Control Technology, Inc. during the 2010 season.

Introduction and Management History

Dudley is a 90‐acre waterbody located in the Town of Wayland, Massachusetts. Eurasian watermilfoil (milfoil) was first confirmed in Dudley Pond in 1991 and several herbicide treatments and non‐chemical control strategies have been employed over the past two decades to manage the infestation.

In 2008, the Wayland Surface Water Quality Committee (WSWQC) prepared a long‐term milfoil management plan that was initiated with a whole‐pond Sonar (fluridone) herbicide treatment program during the 2008 season. A concerted diver hand‐pulling effort was coordinated by WSWQC to remove milfoil root crowns in the late summer and fall of 2008. Despite continuation of an extensive monitoring and diver hand‐pulling program in 2009, a significant and unexpected amount of regrowth was reported by the WSWQC by the end of the 2009 season. After evaluating management alternatives, the WSWQC decided to proceed with a spot‐treatment program using Renovate OTF herbicide in 2010 to control areas with the most extensive milfoil growth. Initially, four locations totaling approximately 15 acres were identified as primary treatment areas and other two locations totaling approximately 3.5 acres were identified as secondary treatment areas.

2010 Treatment Program Chronology A chronology of the 2010 treatment program is provided below:

Order of Conditions and Chapter 194 Permit compliance .........................................(handled by WSWQC 2009‐2010) Pre‐treatment inspection...........................................................................................................................................5/7 DEP License to Apply Chemicals issuance (# 10207) ................................................................................................5/12 Renovate OTF Herbicide Treatment.........................................................................................................................5/19 Triclopyr Herbicide residue monitoring (4 rounds collected by WSWQC) .....................................6/5, 6/21, 7/11, 8/30 Late season survey...................................................................................................................................................9/24

Aquatic Control Technology, Inc. 11 John Road ● Sutton, MA 01590-2509 ● (508) 865-1000 ● Fax (508) 865-1220 ● info@aquaticcontroltech.com

2010 Dudley Pond Renovate OTF Treatment Program Report

2010 Treatment Program Protocol Treatment areas (Figure 1) were finalized following the pre‐treatment survey performed on May 7th. Six areas totaling approximately 18.5 acres were targeted for treatment. Based on the morphology of treatment areas Renovate OTF was selected for use in 2010. Renovate OTF granular was used to minimize dilution and maximize herbicide contact time in these areas. Renovate OTF was applied at 2.0‐2.25 ppm based on the bottom four feet of the water column. By mutual agreement between Aquatic Control Technology and the WSWQC, exposed treatment areas less than 2 acres (Areas 1 and 4) were expanded to approximately 2 acres to further overcome the effects of dilution and maintain adequate concentration‐exposure‐time. Area 2 (1.46 acres) was not expanded since it was located within a shallow and confined cove area.

Table 1: Final Renovate OTF Dosing Area

Acres

Recommended Dose

Pounds of OTF applied

1 2 3 4 5 6 TOTAL

2 1.46 4.94 2 3.25 4.84 18.5

245 215 215 215 215 215

490 315 1065 430 700 1040 4040

WSWQC applied sandbags to the outlet structure prior to treatment to prevent any outflow. On July 5th, nearly 45 days post‐treatment, WSWQC reported that the water level was down approximately 6 inches from the day of treatment and no outflow had occurred.

Summary of 2010 Treatment

Milfoil plants were observed to have more than 3‐4 feet of active growth at the time of the May 7th pre‐treatment inspection. A treatment date of May 19th was selected to allow enough time to comply with the notification requirements of the Wayland Order of Conditions and Chapter 194 permit.

Weather conditions on the day of treatment were overcast with periods of drizzle and light rain. The air temperature was approximately 50° F. Wind was out of the west/northwest, estimated at 5‐10 mph and did not interfere with treatment. Prior to treatment, water temperature was measured using a YSI Temperature/Dissolved Oxygen meter near the deep‐hole location

Table 2: Temperature/Dissolved Oxygen Profile on 5/19/10 Depth (m)

Temperature (°C)

Dissolved Oxygen (mg/L).

Surface 1 2 3 4 5 6

17.5 17.3 17.5 17.5 16.4 15.1 12.2

8.90 8.73 8.72 8.72 8.56 8.45 7.40

Water clarity was measured to be approximately 4.25 meters (14 feet) using a Secchi disk. The pH of the surface water was measured at 7.5 using a Hach colorimeter.

The treatment was using an airboat equipped with a granular eductor spray system that fed the granular herbicide into a stream of water using a calibrated venturi‐type eductor. The mixture was then sprayed off the stern of the boat using fan‐pattern nozzles. A Differential GPS navigation system with the treatment areas pre‐loaded was 2

2010 Dudley Pond Renovate OTF Treatment Program Report

used to insure that the herbicide was evenly applied to the designated treatment areas. A total of 4040 pounds of Renovate OTF (granular) were applied to the designated treatment areas. Actual passes of the treatment boat were recorded with the DGPS unit and are depicted in Figure 1. The herbicide began at approximately 8:25 a.m. and was completed at 11:55 a.m. The treatment was completed in approximately 3.5 hours.

Herbicide Residue Testing Summary Following the treatment, water samples were collected from Dudley Pond by WSWQC for analysis of the remaining in‐pond triclopyr concentrations. A copy of a summary table and chart prepared by M. Lowery of the WSWQC is provided in the Appendix, along with copies of the actual laboratory reports.

The theoretical lake‐wide triclopyr concentration from the 4040 pounds that were applied was 212 ppb. It is unlikely that this concentration was ever present in Dudley Pond at any one time, since triclopyr is released off of the granule over a period of several hours or days. Sixteen days after treatment in‐pond concentration was 97 ppb. At 32 days post‐treatment the concentration had dropped to 40 ppb and at 52 days post‐treatment the concentration was at 52 ppb. Even at 101 days post‐treatment there were still trace levels of fluridone (4 ppb) remaining in Dudley Pond. Triclopyr experienced roughly a 2‐week half‐life in Dudley Pond.

According to the Renovate OTF product label, treated water can be used for potable purposes once the concentration drops below 0.4 ppm (400 ppb). The only water use restriction associated with concentrations less than 400 ppb is not to use treated water for irrigation. This restriction does not apply to established grasses. A label change is pending that will allow for some greater flexibility in the use of treated water for irrigation.

In addition to the in‐pond sampling, WSWQC collected annual samples from the Happy Hollow wells for analysis of triclopyr and fluridone (from the 2008 Sonar treatment) residues on October 14th. Neither herbicide was detected.

Observations of Impacts to Aquatic Plants Approximately 12 days post‐treatment, WSWQC reported that the milfoil plants appeared to be distressed but there was still significant biomass in the water column. The plants reported continued to dieback slowly over the next several weeks. On September 14th, a diver survey from WSWQC reported that no milfoil was found.

Aquatic Control Technology performed its late season survey with M. Lowery of the WSWQC on September 24th.

The majority of the lake perimeter was toured by boat. No milfoil was encountered during the visual inspection or in several rake‐tosses. Non‐target plants that were observed during the survey included:

Table 3: Aquatic plants observed during late‐season survey Species

common name

type

Nitella Najas flexilis Vallisneria americana Potamogeton crispus Chlorophyta Nymphaea odorata

stonewort slender naiad wild celery curlyleaf pondweed filamentous green algae white waterlily

macro‐algae submersed submersed submersed (invasive) algae floating‐leaf

Any impacts to non‐target native plants were not evident by the time the late season survey was performed on September 24th. Some impact to other dicot plants, namely white waterlily, probably occurred immediately after treatment, but the triclopyr concentration was not lethal and the plants recovered by the end of the year. As anticipated, no impact was seen on the other invasive plant in Dudley Pond, curlyleaf pondweed, which is a monocot.

3

2010 Dudley Pond Renovate OTF Treatment Program Report

Summary and Ongoing Management Recommendations

Based on observations by the WSWQC and those made by Aquatic Control Technology on September 24th, the 2010 Renovate OTF herbicide treatment program appears to have achieved complete control of Eurasian watermilfoil. Treating nearly 20% of the pond area and having no outflow for several weeks post‐treatment, probably resulted in prolonged exposure to lethal concentrations of triclopyr, which achieved pond‐wide milfoil control. Some widely scattered milfoil regrowth may be seen in 2011, but will likely become more evident in 2012. Based on past experience at Dudley Pond and in other Northeast waterbodies, if the milfoil is allowed to recover and grow unmanaged, it may reach pre‐treatment densities within 3‐4 years.

WSWQC now has a distinct advantage over the previous treatment programs performed at Dudley Pond, having direct experience and a clear understanding of the effectiveness and limitations of Renovate (triclopyr) herbicide spot‐ treatments, DASH/suction‐harvesting, and diver hand‐pulling. We still feel that an aggressive, integrated management program targeting selective milfoil control will afford the most effective means of preserving desired open‐water conditions and extending the duration of control in Dudley Pond. However, decisions on future management strategies need to be made once the distribution and density of milfoil regrowth can be identified and the cost‐effectiveness of possible techniques can be evaluated. Managing milfoil before it has an opportunity to recover and reestablish its root structures may be a key factor in extending the duration of control.

Specific recommendations for 2011 include:

Regular volunteer monitoring of the lake to identify and document any milfoil regrowth. Locations of any milfoil plants should be recorded using a GPS (if possible) or carefully translated to a scaled‐map to facilitate relocation for follow‐up management efforts. It may also be helpful to physically mark milfoil growth using small buoys as WSWQC has done in prior years.

Develop a management strategy criteria based on milfoil density, distribution and location of growth within the pond. This should help guide decision‐making for future milfoil management expenditures.

Be prepared to implement non‐chemical controls in 2011, as deemed to be appropriate and cost‐effective.

Plan for more substantial non‐chemical controls or herbicide spot‐treatments in 2012, as required.

We trust that this report adequately summarizes the 2010 Renovate OTF herbicide treatment program at Dudley Pond.

We thank Mike Lowery and the rest of the WSWQC for their assistance and oversight on this project and commend you all on your commitment to managing invasive Eurasian watermilfoil growth in Dudley Pond. Please feel free to contact us if you have any questions or require additional information at this time.

Sincerely,

AQUATIC CONTROL TECHNOLOGY, INC.

Marc Bellaud

Gerald N. Smith Senior Biologist

President/Aquatic Biologist

Enclosures: Appendix

4

2010 Dudley Pond Renovate OTF Treatment Program Report

APPENDIX

Figure 1 Dudley Pond Renovate OTF Treatment Areas

Herbicide Residue Data Summary Table and Chart of Results: prepared by M. Lowery Laboratory Reports

5

²

4

2 3

1 6 5

0

100 200

400

600

800

1,000 Feet

Legend:

Planned treatment areas (1=2.00 ac; 2=1.46 ac; 3=4.94 ac; 4=2.00 ac; 5=3.25 ac; 6=4.84 ac)

Dudley Pond Wayland, MA

Actual pass of treatment boat on 5/19/10 recorded by DGPS

2010 Renovate OTF Treatment Areas

bathymetric contour lines, 2-foot intervals

FIGURE:

SURVEY DATE:

MAP DATE:

1

05/19/10

11/03/10

Orthophoto base map source: MassGIS

11 JOHN ROAD SUTTON, MASSACHUSETTS 01590 PHONE: (508) 865-1000 FAX: (508) 865-1220 WEB: WWW.AQUATICCONTROLTECH.COM

DATE 05/19/10 06/05/10 06/21/10 07/11/10 08/30/10 09/19/10

ppb 212 97 40 11 4

interval

days since treatment

%orig 16 16 20 49

45.75% 18.87% 5.19% 1.89%

16 32 52 101 120

ppb 250

200

150

ppb

100

Prepared by: M. Lowery, WSWQC

08/25…

08/18…

08/11…

08/04…

07/28…

07/21…

07/14…

07/07…

06/30…

06/23…

06/16…

06/09…

06/02…

05/26…

0

05/19…

50

Chain of Custody C98875FF-D Customer Company Company Name:

Customer Contact Aquatic Control Technology, Inc.

Contact Person:

Gerald N gnsmith@aquaticcontroltech.com

Address:

11 John Road

E-mail Address:

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

Date Treated

Date Sample Collected

Products

Acres Treated

Rate

Active

Result

1

05/19/2010

06/05/2010

Renovate OTF

18.5

4036

Triclopyr

0.097 ppm

Laboratory Information Date Received:

6/10/2010

Date Analysis Performed:

6/10/2010

Date Results Sent:

6/10/2010

Storage Conditions

Analyzed Immediately

Chain of Custody 271E581F-7 Customer Company Company Name:

Customer Contact Aquatic Control Technology, Inc.

Contact Person:

Gerald N gnsmith@aquaticcontroltech.com

Address:

11 John Road

E-mail Address:

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

1

Date Treated 05/19/2010

Date Sample

Sample Location

Products

Collected 06/21/2010

Renovate OTF

Acres Treated 18.5

Rate

Active

Result

4036

Triclopyr

0.040 ppm

Laboratory Information Date Received:

6/24/2010

Date Analysis Performed:

6/24/2010

Date Results Sent:

6/24/2010

Storage Conditions

Analyzed Immediately

Chain of Custody 6D66DB90-6 Customer Company

Customer Contact

Company Name:

Aquatic Control Technology, Inc.

Contact Person:

Gerald N

Address:

11 John Road

E-mail Address:

gnsmith@aquaticcontroltech.com

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

1

Date Treated 05/19/2010

Date Sample

Sample Location

Products

Collected 07/11/2010

Renovate OTF

Acres Treated 18.5

Rate

Active

Result

4036

Triclopyr

0.011 ppm

Laboratory Information Date Received:

7/13/2010

Date Analysis Performed:

7/14/2010

Date Results Sent:

7/14/2010

Storage Conditions

Analyzed Immediately

Chain of Custody 0E00D8BA-7 Customer Company

Customer Contact

Company Name:

Aquatic Control Technology, Inc.

Contact Person:

Gerald N

Address:

11 John Road

E-mail Address:

gnsmith@aquaticcontroltech.com

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

1

Date Treated 05/19/2010

Date Sample

Sample Location

Products

Collected 08/30/2010

Renovate OTF

Acres Treated 18.5

Rate

Active

Result

4036

Triclopyr

0.004 ppm

Laboratory Information Date Received:

9/1/2010

Date Analysis Performed:

9/1/2010

Date Results Sent:

9/1/2010

Storage Conditions

Analyzed Immediately

Chain of Custody EB0F7C6E-7 Customer Company

Customer Contact

Company Name:

Aquatic Control Technology, Inc.

Contact Person:

Gerald N

Address:

11 John Road

E-mail Address:

gnsmith@aquaticcontroltech.com

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

Date Treated

Date Sample

Sample Location

Products

Acres Treated

Rate

Active

Result

Collected

HH1

05/02/2010

10/14/2010

Renovate 3

18.5

4036

Triclopyr

0.000 ppm

HH2

05/02/2010

10/14/2010

Renovate 3

18.5

4036

Triclopyr

0.000 ppm

Laboratory Information Date Received:

10/20/2010

Date Analysis Performed:

10/20/2010

Date Results Sent:

10/20/2010

Storage Conditions

Analyzed Immediately

Chain of Custody E580862B-5 Customer Company

Customer Contact

Company Name:

Aquatic Control Technology, Inc.

Contact Person:

Gerald N

Address:

11 John Road

E-mail Address:

gnsmith@aquaticcontroltech.com

City:

Sutton

Phone:

State:

MA 01590-2509

Fax:

Invoice

Card Number/Expiration Num:

Waterbody:

Dudley Pond

Waterbody Size (acres):

Depth Average:

8.00

Target Plants

Eurasian Watermilfoil,

Payment Information Payment Type:

Waterbody Information 86.00

Sample Information

Sample Site ID

Date Treated

Date Sample

Sample Location

Products

Acres Treated

Rate

Active

Result

Collected

HH1

07/31/2008

10/14/2010

Wayland Municipal

Sonar A.S.

86

12

Fluridone

<1.0 ppb

HH2

07/31/2008

10/14/2010

drinking water wells

Sonar A.S.

86

12

Fluridone

<1.0 ppb

Laboratory Information Date Received:

10/18/2010

Date Analysis Performed:

10/18/2010

Date Results Sent:

10/18/2010

Storage Conditions

Analyzed Immediately