Project information

Ontario Power Generation Inc. (OPG) is currently in the construction phase of the Upper Mattagami Redevelopment Project to redevelop three (3) hydroelectric generating stations located on the Upper Mattagami River. The stations include:

  1. A map showing the location of the three stations to be redeveloped on the Upper Mattagami River.Wawaitin Generating Station located approximately 25 km southwest of Timmins within the municipal boundaries;
  2. Sandy Falls generating station located approximately 10 km northwest of Timmins within the municipal boundaries; and,
  3. Lower Sturgeon Generating Station approximately 48 km north of Timmins outside of the municipal boundaries.

The Project was subject to the requirements of OPG's Class Environmental Assessment for Modifications to Hydroelectric Facilities (Class EA) under the Ontario Environmental Assessment Act.

A Notice of Project Commencement was issued in April 2006 informing the general public of the details of the undertaking and of an Open House to be held to facilitate public consultation. OPG committed to the conduct of an open and transparent consultation process throughout the Class EA Process with the respective First Nations, government agencies, the public and other interested stakeholders that may be potentially impacted by the proposed Project. Input and comments received were considered and included in the preparation of the Environmental Assessment Report (ER). Two (2) Public Open Houses were held in Timmins at key stages of the process to allow the interested parties the opportunity to speak directly with representatives of OPG and its environmental consulting team.

An ER was completed in March 2007 and is provided in the Supporting Documents page. A Notice of Completion of ERR and Public Review Period was issued in April 2007 to notify the general public of EA completion and the commencement of the 30-day public review period. This Notice is provided in the Notices /Decisions page. The ER identifies a number of commitments (EA commitments), based on the findings of the Class EA, to be achieved by OPG during the design and construction, and operation phases of the Project.

In addition to the EA commitments identified in the ER, a number of environmental permits and approvals have been obtained, as applicable from the responsible authorities, such as the Department of Fisheries and Oceans, Ministry of Environment and the Ministry of Natural Resources, to allow for the conduct of Project activities that could potentially affect the environment. These permits and approvals also contain various terms and conditions which must be met by the Project, such as specific timing in which in-water activities may not be conducted, documentation and monitoring requirements.

Project completion is scheduled for early 2011.

The facilities

The Wawaitin, Sandy Falls and Lower Sturgeon Generating Stations are small run-of the-river hydroelectric facilities that have provided a clean and renewable source of power for over 90 years. All three facilities are now at the end of their designed service life. These three generating stations operate at 25 cycles and therefore the power cannot be used locally in Timmins and instead must be transmitted to Sudbury in order to convert the power to 60 cycles and then be injected into the power grid. Significant energy losses occur during the process of transmitting and converting the 25 to 60 cycle power. All three plants are in need of structural and electrical/mechanical repair in order to continue to provide Ontario with this clean and renewable source of power.

The Wawaitin Generating Station is a 10.4 megawatt facility located within the City of Timmins municipal boundaries approximately 25 kilometers southwest of the urban centre. The plant, placed in service in 1912, is accessed by a municipal road. The Wawaitin Generating Station has a main dam at the northern end of Kenogamissi Lake. The existing powerhouse is operated remotely. Plant operation is controlled to ensure optimal energy production, while satisfying concerns of Kenogamissi Lake cottagers regarding water levels and flooding concerns downstream at Timmins. Typically, water levels are not allowed to fluctuate more than 0.4 m in Kenogamissi Lake during the summer months, with sufficient water passage through the Wawaitin Generating Station (GS) and/or spilling to ensure adequate downstream supply to Timmins and the pulp and paper mill in Smooth Rock Falls. Water level fluctuations must all be in compliance with the Mattagami River System Water Management Plan.

The proposed Wawaitin GS is planned to be located adjacent and to the north of the existing powerhouse. The proposed Wawaitin GS will have two generating units with an approximate capacity of 15 megawatts. Water in the existing intake canal would be conveyed through the existing intake structure via a new steel penstock about 850 meters in length to the new powerhouse and the adjacent substation. The proposed facilities will be connected to the Hydro One Networks Inc. (Hydro One) Timmins Transformer Station at 27.6 kilovolts to feed into the Timmins local distribution system. This penstock system would be buried parallel and to the north of the existing twin penstocks that feed the existing Wawaitin GS. Some refurbishment to the existing dams will be required.

The 3.0 megawatt Sandy Falls GS is located within the Timmins municipal boundaries approximately 10 kilometers northwest of the urban centre. The plant, placed in service in 1911, is well accessed by municipal roads. The Sandy Falls GS receives water upstream of a 216 meters long spillway weir dam across the Mattagami River. As a run-of-the-river plant, the Sandy Falls GS utilizes available water only. Water levels in the headpond are not controlled by plant operation, but are the result of natural water level fluctuations and/or upstream controls and activities. Water levels are maintained to provide sufficient water for Timmins by drawing down the upstream storages when inflows drop in late summer.

The proposed Sandy Falls GS is located adjacent to the east of the existing powerhouse and the new powerhouse will enclose one generating unit with a nameplate capacity of approximately 5.5 megawatts. A water canal will be used to convey water to the new powerhouse using the existing intake structures No. 2 and No. 3. The intake structures and weir dam will also need to be refurbished.

The 5.3 megawatt Lower Sturgeon GS is located outside the municipal boundaries of Timmins and approximately 48 kilometers north of the City. The plant, placed in service in 1923, is accessed by a road west of Highway No. 655. The Lower Surgeon GS has a dam, 165 meters in length, constructed in three differently angled sections, extending across rock outcrops along almost the entire width of the river.

The existing powerhouse is operated remotely. As a run-of-the-river plant, there is no drawdown of the headpond. Any upstream water level fluctuations are the result of natural water levels and/or upstream controls or activities. In most years, sufficient water exists to operate the plant at full-load on a continuous basis. OPG attempts to pass at least 15 m3/s of water at all times for dilution of effluent discharge at the pulp and paper mill at Smooth Rock Falls. In late winter, the forebay is drawn down to provide water to Little Long GS downstream.

The proposed Lower Sturgeon GS is planned to be located at the site of the existing powerhouse and will be redeveloped to produce about 14 MW of power.

The environmental assessment

The redevelopment of the Wawaitin, Sandy Falls and Lower Sturgeon facilities subject to the requirements of OPG's Class Environmental Assessment for Modifications to Hydroelectric Facilities under the Ontario Environmental Assessment Act (EA Act).

An environmental assessment was conducted to examine the effects of the Project on the:

  • Aquatic Environment (water, fish and other aquatic life)
  • Terrestrial Environment (adjacent trees, vegetation and fauna)
  • Socio-Economic Environment (local economy, local social and economic uses)
  • Archaeological and Built Heritage (archaeological, building or structural resources.
  • Atmospheric Environment (air and noise).

Some field work was carried out in 2005, however extensive field work associated with assessing the effects of the Project was conducted in 2006. The effects of the Project both during the construction and operations phases have now been assessed and measures to mitigate, eliminate and reduce negative effects as well as enhance positive effects were identified in the ER. Field work indicated that the environmental impacts associated with the Project would be temporary and minor and could be mitigated.

One (1) ER was prepared for all three (3) generating stations.

Mattagami River System Water Management Plan

A Water Management Plan for the Mattagami River System has been developed and includes eighteen waterpower structures and facilities located along the river system that have influence on levels and flows. The Plan was the result of a partnership between Ontario Power Generation, the Ministry of Natural Resources and other private power producers which operate facilities along the river as well First Nations and the general public, which participated in the form of various advisory committees.

The Water Management Plan was prepared in accordance with the Water Management Planning Guidelines for Waterpower, as approved by the Minister of Natural Resources on May 14, 2002. The Ontario Lakes and River Improvements Act requires compliance by facility operators with the operating regimes (required flows) established in the Water Management Plans and a compliance monitoring program has been established.

June 2010 - Notice of Minor Amendment Inspection

OPG, in consultation with the Ministry of Natural Resources (MNR), is seeking a minor amendment on a temporary basis to the Water Management Plan. This minor amendment will enable OPG to lower the approved minimum upstream water elevation of Lower Sturgeon GS from 257.70m to 256.47m from 1 July 2010 to 31 August 2010. The minor amendment is being sought to enable maintenance work on the spillway of Lower Sturgeon GS. A Notice of Minor Amendment Inspection providing details on the need for this temporary amendment has been issued by OPG through local papers and this website.

Project documents

To request accessible versions of any documents, please contact us.

Through the environmental assessment process OPG is committed to consulting with First Nations, government agencies, the public and other interested stakeholders about the project. OPG wants to hear from people interested in the project. Your input and comments will be considered, documented and included in the preparation of the environmental assessment report.

To encourage public participation OPG will be holding Public Open Houses in Timmins. Stakeholders will have the opportunity to speak directly with representatives of OPG and its environmental consulting team.

Frequently asked questions

OPG is presently engaged in construction work at the Lower Sturgeon GS site in relation to the Upper Mattagami Redevelopment Project. The Interim Minor Amendment will allow the contractor to refurbish the upstream piers and replace them with reinforced concrete and protective steel. The water level conditions required under the interim minor amendment are only required for the duration of the rehabilitation work from July 1, 2010 to August 31, 2010.

Minor amendments are required for changes to the Plan that are anticipated to affect a small geographic scale (i.e., in the vicinity of one dam) and where MNR and the Water Management Plan Steering Advisory Committee agree that the changes will not have a significant impact. OPG is requesting a minor amendment, on a temporary basis to the Mattagami River System Water Management Plan (Plan) under Section 23(1) of the Lakes and Rivers Improvement Act (LRIA) to allow for water levels upstream of the Lower Sturgeon GS to remain below the approved summer levels identified in the Plan.

OPG is requesting MNR to approve an interim minor amendment to the Water Management Plan. The amendment includes temporarily lowering the 2010 summer minimum water elevation constraint for July and August 2010 from 257.70 m to 256.47 m for Lower Sturgeon GS.

No impacts are expected to the aquatic environment. The exceptionally low flow in the river this year resulted in low water levels early and throughout the spring when some fish species spawn in shallow water, forcing them to spawn at lower levels within the reservoir. While most shallow water spawning fish will have finished spawning by July 1, especially during this exceptionally warm spring, any spawning fish or un-hatched eggs or fry remaining in shallow areas will not be affected because further significant reductions in water levels are not anticipated.

OPG is requesting a temporary interim amendment from July 1, 2010 to August 31, 2010.

Without an approved amendment, OPG's contractor will not be able to carry out the refurbishment to the concrete piers in the event the water levels rise naturally during the period the maintenance work will be undertaken.

OPG will temporarily post signs at the area boat launch warning boaters of low water levels. The intent of the summer compliance water level of 257.70 m is to enhance navigation between Sandy Falls GS and Lower Sturgeon GS.

OPG is requesting a change in the summer minimum water elevation from 257.70 m to 256.47 m. This interim amendment will allow the contractor to perform the rehabilitation work and also allow OPG to manage water levels and flows.

The area upstream of Lower Sturgeon GS to Sandy Falls GS will possibly be impacted by the proposed lower summer minimum water elevation.

OPG developed the spillway maintenance work plans that will be enabled by the minor amendment in consultation with the MNR. The MNR Regional Director will take into account public comments in making a final decision on this amendment.

There are several reasons why OPG wants to re-develop these three generating stations:

  • The generating stations are at the end of their current service life and require replacement. Ongoing maintenance of the generating stations will not provide a long-term reliable solution.
  • No replacement parts because 25 cycle equipment is no longer manufactured.
  • These stations can continue to provide Ontario with a reliable, clean and renewable energy resource.
  • There is an opportunity to increase the power produced at these stations by employing modern technology and without changing the current and approved operating regime. The generating stations will continue to operate as run-of-the river facilities and be managed so that there is no change to the water levels and flows.
  • The power from these facilities is currently produced at 25 cycles and cannot be used locally.
  • Producing the power at 60 cycles under the current proposal can allow for its local use.
  • The Proposed Undertaking will free up a transmission corridor from Timmins to Sudbury for Hydro One to use.

There will be no new flooding of land. The Water Management Plan for the Mattagami River legally establishes the operating regimes (water flows and levels) for the three Upper Mattagami Generating Stations, namely Wawaitin, Sandy Falls and Lower Sturgeon.

It is planned that this will be constructed between 2008 and 2009.

A copy of the Water Management Plan can be obtained from the Ministry of Natural Resource Timmins District Office (705) 235-1300.

DISCLAIMER: Please note this website was only actively maintained during the related EA process period. As this process may have closed several years ago, the content of this site may not accurately reflect the current date and may include language with incorrect time references.