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About this Project:

Currently, the MWRA is conducting the Wachusett Dam Lower Gatehouse Pipe Repair Project. The Wachusett Dam Lower Gatehouse serves as a critical component of the Authority’s drinking water distribution system as it serves as an emergency supply from the Wachusett Reservoir to the John J. Carroll Water Treatment Plant, located in Marlborough, MA. When needed, water flows from the Wachusett Reservoir to the Carroll Treatment Plant through three supply lines, located in the Lower Gatehouse, to the Wachusett Aqueduct and then is pumped to the Carroll Treatment Plant utilizing the Wachusett Aqueduct Pumping Station.

In addition, the Lower Gatehouse also releases water to the Nashua River via the 10” diameter fountain line to meet MWRA’s 12 million gallon-per-week statutory requirement. A sliding sleeve valve on the fourth supply line in the Lower Gatehouse is used periodically to release up to 100 million gallons per day to the Nashua River to facilitate the transfer of higher quality water from the Quabbin Reservoir.

The equalizer pipe that interconnects all four supply lines failed in 2018. This failure impacted the ability of the facility to supply water to the Carroll Treatment Plant, as well as impacted the Authority’s ability to release water to the Nashua River. In spring 2020, the MWRA undertook an interim repair project to restore the emergency connection to the Carroll Treatment plant.

Work Includes:

• This project will rehabilitate all four original lines, installed circa 1905, located in the Lower Gatehouse through a combination of replacement and lining.
• The lining portion of the rehabilitation will be accomplished through the addition of carbon fiber reinforced polymer.
• The broken equalizer pipe will be removed, and replaced with four independent supply lines to the Nashua River through the outer ring of the fountain.
• New bathroom facilities located on the first floor of Lower Gatehouse are also included in this project.
• And finally, this project includes hazardous material abatement of the lead-based paint in the administration area of the building and on the original non-operational hydro turbines. This abatement is being done to improve safety for MWRA Operations staff working in the Lower Gatehouse.
  

Schedule:

The construction is expected to be completed in spring 2025.

Wachusett Lower Gatehouse Hazardous Material Abatement Before and After Photos

Equalizer Pipe Demolition Before and After Photos

Layer of Carbon Fiber Reinforced Polymer (CFRP)

48” pipes after final layer of epoxy applied, curing of epoxy in process

 

Wachusett Reservoir North Dike Overtopping Protection Project:

The MWRA is also conducting a separate project in the vicinity of the Wachusett Dam located at the reservoir’s North Dike at the Leominster Pump Station. This project constructs  overtopping protection by raising the embankment area in vulnerable a low spot of North Dike. Importantly, this project will ensure the spillway can properly function and withstand an overtopping event at this North Dike area.

The North Dike will be reconnected to the earthen berm around the Leominster Pump Station to further protect against wave runup/overtopping. A concrete parapet wall will be installed on the west and east sides of the pump station and will be connected to the earthen embankment on both sides.

The project is anticipated to be completed by May 2024.

Excavation for the eastern parapet wall extension to the earthen dike

The western parapet wall being formed, rebarred, and concrete poured

The eastern parapet wall (top of retaining wall) formed, rebarred, and concrete poured

Eastern parapet wall extension to earthen dike completed

Project Updates

Recently Completed Projects:

Wachusett Dam Lower Gatehouse Window and Door Replacement (Contract 7788)

The Wachusett Dam Lower Gatehouse is listed on the National Register of Historic Places as part of the Wachusett Dam Historic District. With the advanced state of deterioration, the MWRA completed the replacement of existing windows and doors for weather protection, security, and operability of the facility. In addition, the replacement of the windows and doors will continue to complement the historic aesthetic of the building. The work under this contract was designed by MWRA staff, and was completed in October 2023.

Before and after photos of the Wachusett Lower Gatehouse Window and Door Replacement Project

Wachusett Dam Bastion Improvements Project (Contract 7697)

The dam and its ancillary structures were built primarily with cast-in-place concrete and stone masonry. The bastion, located at the northerly end of the Wachusett Dam, is an enclosed room measuring approximately 40 feet long by 50 feet wide by 12 feet high, which currently houses mechanical and electrical equipment. The bastion had significant structural and architectural deterioration, including large vertical cracks in the concrete walls and entryway. There were also leaks in the roof, which had resulted in corrosion of the ceiling’s structural beams.

The Wachusett Dam Bastion

The 15-month construction contract, which was substantially completed in February 2023, included the removal and replacement of the top three feet of the bastion’s walls, crack filling and water proofing all walls, providing a new roof and drainage system, and rebuilding the entryway arch and exterior stairway.

Because the bastion is a historic building, construction had to be completed in a manner consistent with MWRA’s Memorandum of Agreement with the Massachusetts Historical Commission. Therefore, the exterior granite blocks were catalogued prior to removal and replaced in the same location upon project completion, so that the building had the same exterior appearance. Some existing granite blocks had been damaged over the years and were in need of replacement. When these instances occurred, granite of similar coloring and form were sourced and used as replacement. The granite used for these replacement blocks was sourced locally and matched the unweathered color of the existing blocks.

 

Reinstalled Granite Stair Treads

Completed Reconstruction -North/East Side of Bastion

Wachusett Dam Lower Gatehouse Bridge Crane Demolition (Contract 7780)

The Wachusett Dam Lower Gatehouse was originally constructed with a bridge crane that was mounted atop a masonry parapet running along the exterior walls of the building. This crane was installed for the maintenance and operation of the Lower Gatehouse hydro turbines. However, the hydro turbines were taken out of service in the 1960s and the bridge crane had not been used in over 20 years. Due to the age and condition of the supporting parapet wall and crane, it was necessary to remove the crane.

Additionally, hazardous materials sampling had identified the presence of lead paint on the crane beams. Prior to the demolition of the crane, which was completed in September 2021, abatement of lead paint was conducted, after which, the crane was removed by erecting staging below the crane, then cutting the crane into smaller pieces and lowering them to the floor.

 

River Road Rehabilitation (Contract 7701)

River Road Before and After Repair

Following historic rainfall that occurred during summer 2021, River Road experienced a significant amount of deterioration. In order to address the roadway, which also serves as critical infrastructure along the Wachusett Reservoir, the MWRA commenced and completed a rehabilitation project later that year, for a new 900-foot-long by 13-foot-wide roadway. This work involved:

• Grading and paving operations;
• The construction of a new guardrail; and,
• The placement of riprap armoring along the slope adjacent to Lancaster Mill Pond.

Significantly, this work required the removal and disposal of approximately 9,050 tons of soil below the road alignment. The removed soils were replaced with higher strength fill to meet slope stability requirements.

Additionally, the project also included a new stormwater system to meet the 100-year design requirements under the Massachusetts Stormwater Guidance Handbook. Components were a detention basin, installation of slotted drainpipe, drain structures, and a stormwater treatment structure to meet water quality standards. The stormwater work also included the demolition of the obsolete upslope drainage system.

Furthermore, final site work was comprised of soil grading, seeding, slope plantings and wetland restoration.

 

Wachusett Dam Lower Gatehouse Interim Pipe Repair (Contract 7379)

The Wachusett Dam Lower Gatehouse is located on River Street in Clinton, MA. It was constructed in 1905 to release water from the Wachusett Reservoir to the Wachusett Aqueduct. Water is withdrawn from the Wachusett Reservoir to the Upper Gatehouse through one of four circular brick lined drop shafts that connect to pipes in the Lower Gatehouse. Lines 1, 2, and 3 discharge water to the Wachusett Aqueduct. Line 4 is used to transfer water from the reservoir to the Nashua River and is connected to the fountain that releases the required 12 million gallons of water per week to the Nashua River.

The equalizer pipe, which was part of the original 1905 piping, failed in the fall of 2018 during testing of the Wachusett Aqueduct Pumping Station, necessitating the MWRA to implement an interim pipe repair project at the Lower Gatehouse. The project focused on isolating Lines 1, 2 and 3 from the broken equalizer pipe and the remaining piping installed in 1905 until this piping could be replaced. Importantly, this work, which was largely completed in May 2020, included the installation of three blind flanges and steel plates for Lines 1, 2, and 3, as well as leakage testing, site restoration and disposal of excess materials.

Dismantling Joint Removed on each of the Three Lines that Supplies the Wachusett Aqueduct

Dismantling Joint Replaced with Cap and Steel Plate to Isolate Lines

Future Work at Wachusett Reservoir Dam:

Additionally, the MWRA anticipates future projects at the Wachusett Reservoir Dam as they are reviewed and coordinated in an effort to keep the facilities in good working order. These projects will include:

• Roof replacement work;
• The repointing of building stones; and,
• Upgrades to the heating system.

Continue to visit MWRA.com for additional updates of ongoing work at the Wachusett Reservoir Dam and other projects occurring throughout the Commonwealth.

 

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