watershed map

Watershed map

The MWRA supplies wholesale water to local water departments in 50 communities, primarily in the Boston metropolitan area. On average, MWRA supplies approximately 200 million gallons per day to its water system customers. MWRA’s water comes from the Quabbin Reservoir, about 65 miles west of Boston, and the Wachusett Reservoir, about 35 miles west of Boston. Both Quabbin and Wachusett Reservoirs are man-made reservoirs, constructed for water supply purposes. More than 50% of the inflow into the Wachusett Reservoir is transferred from Quabbin Reservoir via the Quabbin Aqueduct/Tunnel. From Wachusett Reservoir, the Cosgrove Aqueduct conveys water to the John J. Carroll Treatment Plant (JJCWTP) in Marlborough. After treatment, water is sent eastward via the MetroWest Tunnel or Hultman Aqueduct (back-up).

Project Name Loring Road
LIHI Certificate Number 56
LIHI Effective and
Expiration Dates
April 14, 2015
April 14, 2023
Owner Massachusetts Water Resource Authority
State Massachusetts
Location Located in a valve chamber at the Loring Road Covered Storage Facility in Weston, Massachusetts.
Installed Capacity 200 kW
Average Annual Generation 1,200,000 kWH
Facility Type
FERC No. 13400

Downstream of JJCWTP and close to its centers of demand, MWRA has recently constructed a new network of tanks to protect and store treated drinking water in compliance with the Federal Safe Drinking Water Act. The network of new tanks includes the Norumbega and Loring Road Covered Storage Facilities. From the tanks, water is then distributed to member communities.

The MWRA transmission system consists of over 100 miles of tunnels and aqueducts that transports water largely by gravity to points of distribution within the MWRA service area. There are three locations within this water transmission system where hydroelectric facilities are located. These include: Oakdale at the end of the Quabbin Aqueduct; the Cosgrove Intake to the Cosgrove Aqueduct, and at the Loring Road Covered Storage Facility.

The Loring Road Small Conduit Hydroelectric Facility is located in a valve chamber at the Massachusetts Water Resources Authority’s (MWRA) Loring Road Covered Storage Facility in Weston, Massachusetts. The hydroelectric facility generates power from fully treated potable water as it is transferred via a pipeline from one water supply storage tank in MWRA’s water distribution system (Norumbega) to another storage tank (Loring Road). The hydro facility’s operation is driven by water demand in MWRA’s Low Water Service area, and does not influence or affect withdrawals from MWRA’s source reservoirs more than 30 miles away.

The Loring Road facility establishes the hydraulic grade line of the MWRA’s Low Service Area (areas of lower elevation within the MWRA service area). The water reaches Loring Road at a hydraulic grade line of approximately 282 feet. At Loring Road, the flow is divided; some flow is directed to a supply pipeline serving MWRA’s High Service System, while other flow is directed to pressure reducing valves inside Valve Chamber One, an underground valve chamber. Either the hydro turbine or sleeve valves, or both when water demand is high, are used to reduce the grade line to approximately 200 feet. After the hydro turbine or pressure reducing valves, water is sent via a pipeline to a second valve chamber that directs flows to either Loring Road Storage Tank One or Two. A steady flow rate of 20 mgd can be discharged from Valve Chamber One into the tanks on a nearly constant basis. From the Tanks, flow is discharged to downstream pipelines (Weston Aqueduct Supply Mains) serving MWRA’s Low Service Area. The hydro turbine driven generator provides energy recovery along with the primary purpose of the Loring Road facility to regulate flow and provide a constant pressure water supply to the low service system.

MWRA’s operates the turbine at a relatively constant flow rate averaging around 19-20 mgd (39-31 cfs) year-round except for those seasonal periods when potable water demand is below that rate. During periods of low demand, the turbine operates at a flow that is slightly lower than 19-20 mgd. The net operating head is 70 – 75 feet. A 200-kilowatt (kW) turbine-generator unit is installed; it is a compact design, horizontal Francis turbine with wicket gates utilizing a Francis type runner. The average annual generation over the four years of operation has averaged 1,211,845 kWh. The Loring Road Storage Facility operates 24/7, and the hydroelectric facility is integrated into existing operations.

Certification History

December 7, 2015: LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has certified that the Loring Road Hydroelectric Project (FERC No. P-13400) continues to satisfy the LIHI Certification Criteria. A Preliminary Decision was announced on December 14, 2015, and a 30-day appeal period was open through January 14, 2016. No requests for appeal were received.

The effective certification date for the Loring Road Project is April 14, 2015 for an eight (8) year term, which will expire on April 14, 2023.

October 22, 2015:  The Loring Road Hydroelectric Project has been granted an additional extension; the new expiration date is December 31, 2015.

September 30, 2015 – The Low Impact Hydropower Institute received a complete application for a new term of Low Impact Certification for the Loring Road Hydroelectric project on September 21, 2015.  The application materials can be found in the Files section below.

The public comment period for this application closed on November 30, 2015.

June 19, 2015: The Loring Road Hydroelectric Project has been granted an extension of the current certificate term. The new expiration date is October 11, 2015. See ExtensionLetter_2015Recert for explanation below.

July 21, 2010: The Loring Road Hydroelectric Project has been certified as low impact. Because construction of the Loring Road facility is not expected to be complete until fall of 2010, LIHI certification is granted for an 18 month term beginning on April 14, 2010, with the certification extended for an additional 42 months should the applicant demonstrate to LIHI that it has complied with the conditions contained in the FERC exemption.

June 14, 2010: The public comment period on the application for certification has been closed.

June 9, 2010: LIHI received a comment letter from the USFWS on the Loring Road project. It can be read in the Files section below.

May 4, 2010: LIHI received a comment letter from Dr. David Westerling, P.E. of the Department of Civil Enginerring at Merrimack College. It can be found in the Files section below.

April 14, 2010: The Massachusetts Water Resources Authority has submitted an application for the certification of the Loring Road Hydro Project. A public comment period will remain open for 60 days.


Files: