LIHI Certificate #161 – Oswegatchie River Project, New York

The Oswegatchie River Project is located on the Oswegatchie River in St. Lawrence County, New York. The Oswegatchie River is a 137-mile-long river in northwestern New York and drains over 1,500 square miles. It flows from the Adirondack Mountains north to the Saint Lawrence River. The upper part of the watershed is characterized by rugged mountainous areas with many lakes and ponds feeding the river. The river valley includes many narrow valleys with steep elevation drops before it reaches the level plains near the St. Lawrence River. The project consists of six developments (from upstream to downstream): Browns Falls, Flat Rock, South Edwards, Oswegatchie, Heuvelton, and Eel Weir. The developments were originally constructed in 1913-1928 for the purpose of power generation.

The project includes six developments:

  • Browns Falls: The Browns Falls development includes a 941-foot-long, 69-foot-high concrete gravity dam with a 192.2-foot-long ogee spillway section and 2-foot-high flashboards. A 130.5-foot-long abutment section with a timber parapet wall and a 70-foot-long abutment section are located on the east side of the spillway. A 27.6- foot-long deep gate section is located on the west side of the spillway with a log sluice gate opening and two deep-sluice slide gates. A 62-foot-long intake section and a 458.7-foot-long abutment section are located on the west side of the spillway. The dam creates a 168-acre impoundment. A gated intake structure leads to a 6,000-foot-long steel pipeline (3,600 foot long with12 ft diameter, reducing to 2,388 foot long with 11 ft diameter) and a surge tank which leads to two 8 ft diameter, 142-foot-long steel penstocks. The powerhouse contains two vertical Francis turbine units with a combined capacity of 15 MW. The dam creates a 7,500-foot-long bypassed reach.
  • Flat Rock: The Flat Rock dam is a 568-foot-long, 80-foot-high concrete gravity dam that includes a 229-foot-long ogee spillway section and a 7-foot-wide, 4-foot-high sluice gate opening. A 120-foot-long earthen embankment section with a concrete core wall is located on the east side of the spillway. A 95-foot-long abutment section with a timber parapet wall exists on the east side of the spillway. The 66-foot-long intake section is found the west side of the spillway along with a 14-foot-long gate section with a 6-foot-high, 5-foot-wide sluice slide gate. There is a 134-foot-long abutment section on the west side of the spillway with a 66-foot-long, 42-foot-high gated intake structure with two 16-foot-high, 14.25-foot-wide headgates. The 85-foot-long, 66-foot-wide concrete-brick powerhouse contains two vertical Francis turbine-generating units with a combined capacity of 5.07 MW, and flows exit via a 25-foot-long concrete-walled tailrace. The powerhouse is integral with the dam; therefore, there is no bypassed reach.
  • South Edwards: The South Edwards development consists of a 233-foot-long, 48-foot-high dam that includes an 88-foot-long, concrete gravity ogee spillway section with 2-foot-high pneumatic flashboards; a 13.5-foot-long abutment section and a 17-foot-long abutment section with 9 ft wide log sluice gate on the east side of the spillway; a 46-foot-long intake section on the west side of the spillway; and a 42-foot-long abutment section on the west side of the spillway. There is a 573-foot-long earthen embankment and a 245-foot-long earthen embankment located upstream on the west side of the dam, each with concrete core walls and 12-inch-high flashboards. The dam creates a 79.2-acre impoundment. The intake structure leads to a 10 ft diameter, 1,142-foot-long fiberglass pipeline, a 4-foot-diameter butterfly valve and a 4-foot-diameter, 30-foot-long pipe connecting to the fiberglass pipeline and containing a minimum flow submersible Flygt turbine-generating unit rated at 0.24 MW. A surge tank with a 4-foot-diameter, 63-foot-long overflow pipe connects to the fiberglass pipeline. The powerhouse contains three horizontal Francis turbines with a combined capacity of 2.92 MW, including the 0.24-MW minimum flow unit. The dam creates a 1,500-foot-long bypassed reach.
Project Name Oswegatchie River
Owner Erie Boulevard Hydropower LP (Brookfield Renewable Energy Group)
LIHI Certificate No. 161
LIHI Certificate Term May 17, 2019 - May 16, 2024 (option to extend to May 16, 2027)
State New York
Location Located between river mile 5.1 and 96.9 on the Oswegatchie River
Installed Capacity  Total: 28.56 MW Browns Falls: 15.00 MW Flat Rock: 5.07 MW South Edwards: 2.92 MW Oswegatchie: 2.07 MW Heuvelton: 1.04 MW Eel Weir: 2.46 MW
Average Annual Generation  Total: 110,411 MWh Browns Falls: 55,741 MWh Flat Rock: 16,095 MWh South Edwards: 17,249 MWh Oswegatchie: 8,080 MWh Heuvelton: 4,424 MWh Eel Weir: 8,822 MWh
Facility Type The four upstream developments (Browns Falls, Flat Rock, South Edwards, and Oswegatchie) are operated as peaking facilities. The two downstream developments (Heuvelton and Eel Weir) operate in a run‐of‐river mode.
FERC No. P-2713 issued 2012, expires 2052
  • Oswegatchie: The Oswegatchie development consists of a 160-foot-long, 12-foot-high dam that includes an 90-foot-long, 12-foot-high concrete gravity spillway section; a 30-foot-long bedrock outcrop section on the west side of the spillway; and a 29-foot-long intake section on the west side of the spillway. The dam creates a 6-acre impoundment. The intake structure leads to 75.5-foot-long steel penstock and a 6.5- foot-diameter, 65-foot-long steel penstock. The powerhouse contains two vertical Kaplan turbines with a combined capacity of 2.30 MW. The dam creates a 350-foot-long bypassed reach.
  • Heuvelton: The Heuvelton development consists of a 285-foot- long, 19-foot-high concrete gravity dam and spillway topped with two 28-foot-long, 11.1-foot-high inflatable rubber bladder gates and four 28-foot-long, 10.5-foot-high Tainter gates. The dam creates a 239-acre impoundment. The 70 ft long intake structure leads to the powerhouse which contains two vertical Francis turbines with a combined capacity of 1.04 MW. The powerhouse is integral with the dam; therefore, there is no bypassed reach.
  • Eel Weir: The Eel Weir development consists of a 965-foot- long, 26-foot-high dam that includes a 774-foot-long, 26-foot-high Ambursen spillway section with a 39 ft long log sluice gate and two deep-sluice slide gates; a 73.5- foot-long abutment section on the east side of the spillway; a 117.25-foot-long intake section on the east side of the spillway and a 160-foot-long earthen embankment section on the west side of the spillway. The dam creates a 96-acre impoundment. The intake structure leads to the powerhouse which contains two propeller-type turbines rated at 1.0 MW and one vertical Francis turbine rated at 0.46 MW, for a total installed capacity of 2.46 MW. The powerhouse is integral with the dam; therefore, there is no bypassed reach.

The project operates in a peaking mode at the four upstream developments. Heuvelton and Eel Weir are both operated in a run-of-river mode with a 0.5-foot fluctuation limit. The developments each have individual flow provisions:

  • Browns Falls operates in tandem with Flat Rock as a peaking facility to increase generation during periods of high electricity demand. The impoundment fluctuates on a daily cycle, typically drawing down when the demand for electricity increases and refilling when demand decreases. The development operates with a maximum impoundment fluctuation of four feet from July 15 through March 14, and two feet from March 15 through July 14. Fluctuations greater than 3 feet occur infrequently. The two-foot-high year-round flashboards are designed to fail when overtopped in excess of 2 feet of river flow. A minimum flow of 30 cfs is provided year-round in the bypassed reach.
  • The Flat Rock development operates with a maximum impoundment fluctuation of four feet from July 15 through March 14, and two feet from March 15 through July 14. A minimum base flow of 160 cfs is provided year-round from the powerhouse.
  • The South Edwards development operates with a maximum impoundment fluctuation of six feet from July 15 through March 14, and two feet from March 15 through July 14. The two-foot-high pneumatic flashboards operate to maintain impoundment levels. A minimum flow of 60 cfs year-round into the bypassed reach is typically provided by the minimum flow unit.
  • The Oswegatchie development operates with a maximum impoundment fluctuation of 0.4 feet. A minimum flow of 40 cfs year-round into the bypassed reach is provided by a minimum flow notch in the spillway.
  • The Heuvelton development operates in a run-of-river mode with a maximum impoundment fluctuation of 0.5 feet. A minimum base flow of 275 cfs year-round is provided from the powerhouse.
  • The Eel Weir development operates in a run-of-river mode with a maximum fluctuation of 0.5 feet. A minimum base flow of 325 cfs year-round is provided from the powerhouse.

Waters within the project reach are designated as Class C from the Browns Falls impoundment through the downstream reach of the Oswegatchie development. The waters at the Heuvelton and Eel Weir developments are designated as Class B waters. The New York State Department of Environmental Conservation’s (NYSDEC) 2016 Section 303(d) list of impaired waters indicates that no waters in the project reach are impaired for any standards.

Resource agencies have not prescribed fish passage facilities at any of the six developments. However, lake sturgeon, American eel, and other migratory fish are known to access Heuvelton and Eel Weir’s river reaches. Thus, the project owner began the process of designing and installing nature-like fishways at the two developments voluntarily to facilitate passage for these species. At Heuvelton, the upstream passage facilities consist of an excavated bypass channel with reinforced concrete walls beginning on the left side of the powerhouse tailrace, running overland around the left side of the powerhouse and reentering the river upstream of the powerhouse. The channel consists of a series of gapped boulder weirs and pools with a minimum depth of two-feet, and a thalweg depth of three-feet at each weir separated by pools up to six-feet deep. Under normal operations, the fishway will have approximately 45 cfs of flow. The upstream passage structure is operated from March 15 through November 30 each year. At Eel Weir, the fishway consists of an excavated bypass channel downstream of the spillway containing a series of gapped boulders and pools with a minimum depth of 2 feet. Under normal operations, the fishway hass approximately 45 CFS of flow. The upstream passage structure is operated from March 15 through November 30 each year.

The passage facilities open up 50 miles of additional fish habitat for resident river species including pumpkinseed, yellow perch, bluntnose minnow, golden shiner, smallmouth bass, largemouth bass, walleye, and pike. Trashracks with 1-inch spacing mitigate the potential for entrainment at the developments during downstream passage which is assisted by minimum flows in the bypassed reaches and tailraces of each development.

The project lands consist of 375-acres across the six developments. The lands surrounding the project are mostly hardwood-conifer forest at the four upstream developments, and mostly agricultural lands mixed with some northern hardwood forest at Heuvelton and Eel Weir. Heuvelton has suburban development while the others are mostly undeveloped. Deep and shallow marshes, shrub swamp wetlands, and floodplain forests are common along the project length. While there are some areas considered to be of significant ecological value in the project vicinity, they are not under the direct or indirect control of the project owner. The owner established and contributes to the River Management Fund used for projects, studies, and services pertaining to ecosystem restoration, natural resource stewardship, public education, research, recreation resources, and improving public access.

Threatened or endangered species potentially present in the project vicinity include:

  • Northern long-eared bat at all developments;
  • Common loon at Browns Falls, Flat Rock, South Edwards, and Oswegatchie;
  • Eastern sand darter at Heuvelton and Eel Weir;
  • Lake sturgeon at Heuvelton and Eel Weir;
  • Mooneye at at Heuvelton and Eel Weir;
  • Blanding’s turtle at Heuvelton and Eel Weir.

These species were identified via consultation with NYSDEC’s Natural Heritage Program. Protection measures have been implemented at each development for the Northern long-eared bat which primarily focuses on prohibiting tree-clearing operations from June 1 through July 31 to reduce impacts to roosting habitat. Loon nesting platforms were installed at the Browns Falls and Flat Rock developments and monitoring of nesting habitat was conducted for 5 years, completed in 2017. Fishing line recycling containers are installed at the developments to prevent loons from becoming entangled. The nature-like fishways at the Heuvelton and Eel Weir developments are consistent with recovery plans for the sand darter. Run-of-river operations at the downstream developments provide additional protection to the listed species potentially found in the area.

In 2010, the project owner consulted with the New York Historic Preservation Office (SHPO) which determined that the Browns Falls, Flat Rock, South Edwards, Heuvelton, and Eel Weir development’s hydroelectric facilities were all eligible for listing on the National Register of Historic Places. Additionally, the Browns Falls Mill Complex Historic Site and Flat Rock Historic House are located in the project area. A historic properties management plan was developed in consultation with the SHPO which includes provisions for the proper stewardship of the historic properties at the project.

Recreational resources at the project include:

  • Canoe portage, picnic area, and fishing access at Browns Falls;
  • Boat launch, floating dock, canoe portage, fishing access, picnic area, and an educational/historical kiosk at Flat Rock;
  • Two portage takeouts in the impoundment, one closer to the dam for through paddling, and a put in below the dam, and a picnic area at South Edwards;
  • Portage route with warning signage detailing rapids downstream at Oswegatchie;
  • Day use area and canoe portage at Heuvelton; and
  • Canoe portage at Eel Weir.

Public access is provided free of charge where safety concerns and private property do not preclude access.


Certification History

September 9, 2019: The decision to certify the Oswegatchie River Hydroelectric Project is final. No appeals were received during the appeal period which closed on September 8, 2019. The certification term for the Project is from May 17, 2019 through May 16, 2024. The Certification includes four conditions:

  • Part b) satisfied 2020. Condition 1: By no later than the first annual certification submittal to LIHI after certification the Facility Owner shall: a) Institute an annual review for appropriate personnel that reinforce each development’s proper operation and environmental flow requirements. Documentation stating the personnel attending and a summary of the material discussed shall be provided in annual compliance submittals to LIHI; and b) Provide a copy of the final procedure developed for Eel Weir to help eliminate future base flow deviation occurrences. Copies of any FERC filings, approvals, and consultation summaries should also be provided in annual compliance submittals to LIHI.
  • Condition 2: The Facility Owner shall provide a summary of the effectiveness testing of the nature-like fishway at Heuvelton when testing is complete. Copies of any FERC filings, agency approvals, and consultation summaries should also be provided in annual compliance submittals to LIHI until testing is completed. LIHI reserves the right to modify certification based on upstream passage effectiveness results. Option to extend term by 3 years for PLUS pending satisfaction of Condition 2 and provided effectiveness testing is satisfactory.
  • Condition 3: The Facility Owner shall provide a status update pertaining to the installation of 1-inch trashracks at the Browns Falls, Flat Rock and South Edwards in annual compliance submittals to LIHI. Copies of any FERC filings, approvals, and consultation summaries should also be provided to LIHI.
  • Satisfied 2020. Condition 4: The Facility Owner shall provide a copy of the report to be submitted to FERC detailing the completion of the proposed recreational facilities no later than February 27, 2020.

August 8, 2019: The Low Impact Hydropower Institute has preliminarily approved Low Impact Certification for the Oswegatchie River Hydroelectric Project.

This decision is preliminary pending the 30-day appeal window. Only those who commented on the initial application during the 60-day comment period are eligible to file an appeal. Such appeal needs to include an explanation as to how the Project does not meet the LIHI criteria. Appeal requests can be submitted by email to comments@lowimpacthydro.org with “Oswegatchie Hydroelectric Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 6, Lexington, MA 02420. All requests will be posted to the website.  The applicant will have an opportunity to respond and any response will also be posted. Requests must be received by 5 pm Eastern time on September 8, 2019.  The full application and reviewer’s report are available below.

If no appeal requests are received and the decision becomes final, the Certification term for the Project (pending LIHI #161) will be May 17, 2019 for a term of five (5) years, which will expire on May 16, 2024.

May 20, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Oswegatchie Hydroelectric Project.  LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s application materials below.

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 comments@lowimpacthydro.org with “Oswegatchie Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420.  Comments must be received on or before 5 pm Eastern time on July 19, 2019 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.