fishway photo2 - LO RES

Holyoke Gas and Electric Hydropower System

Holyoke Dam, the first dam on the main stem of the Connecticut River upstream of Long Island Sound (River Mile 87). The dam and its associated hydroelectric facilities at the dam and in the canal system are located in Holyoke and South Hadley, Massachusetts 12.6 miles north of the Connecticut state line.

HG&E owns and operates hydroelectric facilities at Holyoke Dam (the Hadley Falls Station) and in the Holyoke Canal System.

Project Name Holyoke
LIHI Certificate Number 89
LIHI Effective and Expiration Dates January 1, 2012
January 1, 2017
(extended to June 1, 2017)
Owner City of Holyoke Gas & Electric Department
State Massachusetts
Location Located in Holyoke and South Hadley, Massachusetts, 12.6 miles north of the Connecticut State Line.
Installed Capacity See table below.
Average Annual Generation See table below.
Facility Type Run-of-river
FERC No. See table below.

The dam and canal system were conceived and constructed as one system by the South Hadley Falls Company starting in 1847-1848. The purpose of the system was to harness the power of the falls by diverting water from the Connecticut River to mills for mechanical power for manufacturing. The first hydroelectric turbine was installed within the canal system in 1888. Holyoke Dam continued to be used solely for diversion of flow until 1950 when the first hydroelectric turbine was installed; a second unit followed in 1983.

Holyoke Dam, of rubble masonry construction finished with ashlar granite, extends 1,020 feet from bank to bank. Founded on bedrock, it is 30 feet high. In 2001, HG&E installed five 3.5- foot-high, inflatable flashboard sections to replace the wooden flashboards. The inflatable flashboard system extends across the entire crest, except at the south end adjacent to the powerhouse intake, where a 25-foot-wide bascule gate with a permanent crest elevation of 94.60 feet is located. The air pressure in the flashboard system is regulated as necessary to prevent the 18-mile-long impoundment from rising above a maximum elevation 100.6 feet msl. [1]

Hadley Falls Station 

Hadley Falls Station is integral with the dam’s south abutment. Four gated openings admit water to two 28-foot-diameter reinforced concrete penstocks that serve the two generating units. Hadley Unit 1, the older 1950 unit, consists of a full Kaplan (double regulated) turbine and a 15.8 MW generator; its hydraulic capacity is 4,500 cfs. Hadley Unit 2 consists of a turbine with a fixed blade propeller and a 15 MW generator; its hydraulic capacity is 3,750 cfs. Flows passed through the Hadley Falls Station are discharged into a 2,750-foot-long tailrace, a walled channel between the shore and the riverbed.

Holyoke Canal System 

The canal system begins at a gatehouse structure located directly upstream of Hadley Falls Station. The canal system consists of three levels. Within the canal system, HG&E owns eighteen stations, two of which, Crocker Mill A and B and Crocker Mill C, are no longer operating and are scheduled for decommissioning. Most of the HG&E canal system hydroelectric units are located within buildings that are used for unrelated light commercial or industrial purposes.

The First Level Canal is a subsystem about 6,500 ft long. Stations located between the First Level Canal and the Second Level Canal utilize the 20 feet of available gross head between elevation 97.5 feet msl and elevation 77.5 feet msl. Six HG&E stations are so located, as are two privately owned stations, Open Square (a.k.a. Aubin Station) and Parsons. Open Square was certified by LIHI at the Governing Board’s May 3, 2012, meeting. Parsons no longer operates as it has been partially demolished due to a fire.

The Second Level Canal includes nine in-service generating stations; the No. 2 Overflow structure that discharges into the Hadley Falls Station tailrace; the No. 3 Overflow; and a pipe that discharges to the Third Level Canal. Stations on the Second Level Canal are either located between the Second Level Canal and the Connecticut River (discharging about 3,500 ft north of the Boston & Maine Railroad bridge).

The Third Level Canal is supplied with water from the Holyoke 3 station and the No. 3 Overflow. It is about 4,000 ft in length and is located largely at the low-lying southern end of the Canal system in the City of Holyoke, mostly parallel to the bank of the Connecticut River. The Third Level Canal includes the No. 4 Overflow structure located between the Canal and the Connecticut River. The Chemical (FERC No. 2004) and Sonoco (unlicensed and not owned by HG&E) stations are located between the Third Level Canal and the Connecticut River, discharging about 3,400 ft south of the railroad bridge.

A downstream fish passage louver facility, further described in the Fish Passage section, is located in the canal starting about 554 feet downstream of the canal gatehouse. The No. 1 Overflow structure, which is located immediately downstream of the gatehouse, discharges water directly back to the Hadley Falls Station tailrace, or to the fish lift attraction water.

[1] Condition 10 of the water quality certification issued in 2001 for licensing of the Holyoke Project required the installation of the inflatable flashboard system in order reduce impoundment fluctuations and help attain run-of-river conditions.


Aerial View

Project Name FERC No. Installed Capacity (KW) Average Annual Generation (MWH)
Boatlock Station 2004 3,230 13,167
Beebe-Holbrook Station 2004 250 806
Skinner Station 2004 300 841
Holyoke 1 2386 1,056 3,187
Holyoke 2 2387 800 4,670
Holyoke 4 7758 375 1,440
Riverside 2004 7,040 30,094
Station No. 5 10806 790 3,267
Crocker Mill A & B 2758 350 n/a
Crocker Mill C 2770 350 n/a
Albion Mill D 2766 500 761
Albion Mill A 2768 312 779
Mt. Tom Mill 2497 500 1,378
Nonotuck 2771 500 1,045
Gillmill A 2772 450 1,183
Gillmill D 2775 450 1,159
Holyoke 3 Station 2388 450 2,225
Chemical 2004 1,600 5,423


Certification History

April 21, 2017: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Holyoke Hydroelectric project. The application materials can be found in the Files section below.

LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Holyoke project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook released in March 2016.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s 2016 application materials posted on the project page.

Comments that are directly tied to specific LIHI criteria (flows, water quality, fish passage, etc.) will be most helpful, but all comments will be considered.  Comments may be submitted to the Institute by e-mail at with “Holyoke Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, PO Box 194, Harrington Park, New Jersey 07640.  Comments must be received at the Institute on or before 5 pm Eastern time on June 21, 2017 to be considered.  All comments will be posted to the web site and the applicant will have an opportunity to respond.  Any response will also be posted.

December 16, 2016: The Holyoke Hydroelectric project has been granted an extension of the current certificate term. The new expiration date is June 1, 2017. See extension letter for explanation below.

July 26, 2012: The Holyoke Hydropower System has been certified as low impact for a five year term, effective January 1, 2012 and expiring January 1, 2017, with the following conditions:

  1. If HG&E does not meet any of the downstream fish passage design and implementation deadlines that fall within the 5-year term of certification, LIHI will suspend certification unless HG&E demonstrates to LIHI that the resource agencies believe good cause exists for the schedule delay. Any subsequent re-certifications of the Facility will be dependent on HG&E’s passage facilities meeting effectiveness targets set by the agencies.
  2. HG&E shall either 1) restore the Shad Derby to two May weekends per year starting with May 2013 and at a minimum through the term of this certification, or 2) shall sponsor the Shad Derby for only one May weekend per year but only if the change from two weekends to one is approved by FERC based on an application to amend the Project 2004 recreation plan, with full consultation of Resource Agencies and interested NGOs. Should HG&E seek to amend the recreation plan, the Shad Derby shall be sponsored for two weekends per year until such time as FERC acts. HG&E shall inform LIHI of its decision by October 1, 2012. If it chooses to seek to amend the recreation plan, it shall notify LIHI of FERC’s final decision within 30 days of issuance. Continued non-compliance with this element of the recreation plan shall result in immediate revocation of this certification. Should HG&E obtain a written determination from FERC that the change from two weekends to one is not subject to FERC approval, HG&E shall provide LIHI with a copy of the determination and this condition shall become nullified.

May 14, 2010: The Holyoke Gas and Electric Department has submitted an application for certification of the HG&E Hydroelectric System.

fishlift diagram lo-res with labels


2017 Re-certification

2012 Certification