HANSON CONSERVATION COMMISSION
MINUTES OF THE PUBLIC MEETING OF NOVEMBER 18, 2014
TOWN HALL, 542 LIBERTY STREET, HANSON, MA
Called to Order at 7:00 PM under M.G.L. c 131, §40 and the Hanson By-Law 3-13, §5 and Rules and Regulations by John Kemmett, Chairman, in Meeting Room D (Historic Room) at the Town Hall.
Present: John Kemmett, Chairman
Frank Schellenger, Vice Chairman
Brad Kirlin, Member
Absent: Phil Clemons, Associate Member
Also Present: Laurie Muncy, Agent
Rebecca Nehiley, Administrative Assistant
Minutes
Motion to approve minutes of October 28, 2014: Frank Schellenger
Second: Brad Kirlin
Vote: 3-0-0
Public Hearings
7:00 PM Notice of Intent for repairs to the Factory Pond Dam at 0 Winter Street Rear (behind 901 Winter Street), Map 114 (Hanson), Lot 9A (Hanson) for the Hanover & Hanson Conservation Commissions represented by Amory Engineers, P.C., 25 Depot Street, PO Box 1768, Duxbury, MA (DEP #SE175-0655) (New Hearing)
Mr. Brad Kirlin read the Public Hearing Notice and the abutters were verified. Mr. Patrick G. Brennan, P.E. of Amory Engineers made the presentation for the repair of Factory Pond Dam which is jointly owned by the Towns of Hanover and Hanson. During the Phase I Inspection/Evaluation of the dam in December of 2011, it was determined that the dam was in poor condition. One of the deficiencies identified were significant cracks in the walls of the concrete sluiceway, also known as the primary spillway, adjacent to the foundation of the ski shop. In addition, dense brush and large trees have established themselves on the upstream and downstream embankment slopes which may compromise the structural safety of the dam. A small area of
rip-rap has been dislodged from the downstream face of the auxiliary spillway and has to be picked up and put back. The upstream slope of the left embankment is really “where the concerns are.” The face of it has really eroded over the years and the integrity of the dam in that location is “suspect at this point in time.”
Subsequently, a Phase II Investigation was done during which a structural and hydraulic analysis of the dam and spillway were done that led a procedure to bring the dam into compliance. Mr. Brennan said that they have received permission from the Office of Dam Safety to do the work, but Orders of Conditions from both towns have to be obtained before moving forward. He presented a Plan dated 7/23/14 and rev. 10/1/14 that depicted the following repairs:
- Removing all trees, brush and root systems from the dam and establishing ground cover on the embankments.
- Raising the embankment sections to provide for adequate protection from overtopping. Amory’s hydraulic analysis indicated that there is a concern the embankment section could wash out during a 100-year storm event. For that reason, they are proposing to raise the elevation of the embankment to 50.7 feet
Reconstructing the upstream and downstream slopes of the left embankment to provide a consistent, sloped face and armoring the slope with riprap stone. A Geo-cellular Confinement System is proposed on top of the embankment face. This is a plastic 3-dimensional material that will reinforce the slope.
Replacing and/or resetting riprap stone on the downstream face of the auxiliary spillway right contact.
Repairing the damaged spillway walls by injecting grout into the cracks and re-facing the concrete.
Establish an Operation and Maintenance Program mainly for routine inspections and mowing.
Mr. Brennan added that a wetland replication area will be proposed because 470 square feet of wetland has to be filled to re-grade the slope. Mr. Schellenger asked if any abutters were present. Those present were:
Jean Keily, Broadway Street, Hanover – Asked if the repairs to the dam would have any influence on the amount of flooding. Also when was the dam built? Mr. Brennan answered that it would have no impact on flooding and the dam was built between 40 and 50 years ago. Moreover, Ms. Keily asked what would happen if the dam failed. Mr. Brennan was of the opinion that if the concrete failed, it could cause issues to the foundation of the ski shop and a breach would empty out a good portion of the pond.
Denis Donaghey, Winter Street, Hanson – Commented that he had been around for the previous repairs and had a question about the elevation of the weir.
Mr. Kemmett asked what the life expectancy of the repairs would be. Mr. Brennan said that typically, for this type of product, it’s about 10-15 years and he would be able to provide the specifications for that. Ms. Muncy inquired as to who would be writing the Request for Proposals for the work. Mr. Brennan said that their company would be responsible for providing the specs and the plans. Mr. Schellenger asked if an emergency plan was required in addition to the Operation and Maintenance Plan. Mr. Brennan said that an emergency plan was not required as part of this process. Mr. Schellenger asked if the question from the Department of Environmental Protection about whether the project would trigger a Chapter 91 review had been resolved.
Mr. Brennan answered that he still has to check with a Mr. David Hill who administers the MassDEP Waterways Program at the Southeast Regional Office. In conclusion, Mr. Schellenger had concerns of how they were preventing sediments from getting out during a drawdown. Mr. Brennan suggested that certainly an additional turbidity curtain could be added across the front of the spillway.
Motion to continue to December 9, 2014 at 7:00 PM pending several requests for information and a revision to the Plan: Frank Schellenger
Second: Brad Kirlin
Vote: 3-0-0
Old Business/New Business
Signatures for receipt of Open Meeting Law Packet - signed
Whitman-Hanson Express/Invoice – signed
Consultant Review/Invoice – signed
Adjournment
Motion to adjourn at 7:40 PM: Frank Schellenger
Second: John Kemmett
Vote: 3-0-0
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