Wuskwatim Generating Station

For a high level overview of this and other hydro projects see Hydroelectric Development in Northern Manitoba.

Background
The Wuskwatim GS location was identified by Manitoba Hydro as a potential hydroelectric development site following the implementation of the Churchill River Diversion (CRD) in 1966. The site became a higher potential resource option once the CRD began operating in 1976. The project was committed to in the summer of 2006 to meet the needs of continued load growth following a rigorous regulatory review process. The Wuskwatim GS was developed, and is owned by, the Wuskwatim Power Limited Partnership (WPLP) a legal entity involving Nisichawayasihk Cree Nation (NCN) and Manitoba Hydro. Manitoba Hydro operates the Wuskwatim GS as part of the Manitoba power grid on behalf of WPLP.

Location
The Wuskwatim Generating Station (GS) is located at a site previously known as Taskinigup Falls (Photo 1) on the Burntwood River, one mile (1.6 km) downstream of Wuskwatim Falls, which is the natural outlet of Wuskwatim Lake. The Wuskwatim GS is approximately 23 mi (37 km) southeast of community of Nelson House and 28 mi (45 km) southwest of the City of Thompson.



Principal Works
Wuskwatim GS spans a total of 0.4 mi (0.6 km) across the Burntwood River and consists of a closecoupled intake/powerhouse with three units, a non-overflow concrete dam, a concrete wing wall, a main dam, a dyke to contain the immediate forebay, and a three-bay gated spillway (Photo 2; Map 1). The immediate forebay is the area between generating station principal works and Wuskwatim Falls. The immediate forebay area and Wuskwatim Lake together form a reservoir that is typically referred to as the forebay. Channel improvements were undertaken at Wuskwatim Falls to increase the outflow capability of the lake.





Project Data

 * Turbine Generator Units:
 * Type: 3 vertical shaft fixed blade propeller turbines
 * Capacity: 214 MW (63rd Annual Report, Mar. 2014)
 * Powerhouse:
 * Length: 246.16 ft (75.03 m)
 * Waterfall drop: 70.2 ft (21.4 m)
 * Discharge capacity: 38,846 ft3/s (1,100 m3/s)
 * Main Dam:
 * Length: 1,056 ft (322 m)
 * Maximum height: 46.3 ft (14.1 m)
 * Spillway:
 * Number of bays: 3
 * Length (of all bays): 141.08 ft (43.0 m)
 * Discharge capacity: 81,577 ft3/s (2,310 m3/s)
 * Reservoir/Forebay Elevation:
 * Full supply level (maximum): 767.71 ft (234.0 m)
 * Normal minimum operating forebay elevation: 766.89 ft (233.75 m)
 * Flooded Area: 0.1 mi2 (0.4 km2)

Supporting Infrastructure
Access to the Wuskwatim GS site is from the north via a 29.8 mi (48 km) permanent gravel access road from PR 391, approximately 32 km west of the City of Thompson.

Generation Outlet Transmission
Development of the Wuskwatim GS required the development of new transmission lines and transmission stations in order to deliver the generated electricity into the existing transmission system. The points of connection are to a new Birchtree Station at the City of Thompson and to the existing Herblet Lake Station north of the community of Snow Lake.

The new transmission facilities include the following:


 * a new 230 kilovolt (kV) switching station at the Wuskwatim GS site;
 * a new switching station (Birchtree Station), just south of the City of Thompson;
 * a new 230 kV transmission line (W76B) to connect the Wuskwatim Switching Station to the Birchtree Station. This line was the first built and was initially used to provide construction power for development of the proposed generating station (Figure 1);
 * two new 230 kV transmission lines (W73H and W74H) between the Wuskwatim Switching Station and the existing Herblet Lake Station, to the north of the community of Snow Lake (Figure 1); and
 * a new 230 kV transmission line from the Herblet Lake Station to the Rall’s Island Station at The Pas.



Principle Structures
Construction began in 2006 when clearing for the site access road and start-up camp got underway. Over a two year period, the access road was constructed, borrow areas were developed, and the site construction camp built adjacent to the future location of the generating station.

Work on the generating station began in late 2007 with the opening up of a rock quarry, impervious and granular borrow areas, and construction of cofferdams to isolate the area for the spillway, powerhouse and exit channels to be built. River diversion through the completed spillway structure took place in 2010, allowing for construction of the Stage II cofferdams and the permanent main dam across Taskinigup Falls (Photo 3). The stations three generating units went into commercial service between June and October 2012 (Photo 4).

All of the construction workforce lived in camp for several weeks at a time and travelled to their homes during their days off. Decommissioning of construction facilities and restoration of the site continued through 2013 and 2014.





Construction Infrastructure
A temporary construction camp and work areas (Photo 5) were established near the site. The construction camp comprised of accommodations for upwards of 840 workers, a dining complex, a recreation centre, and a lounge. Construction power was brought in by pre-building the 230 kV transmission line (W76B) from the City of Thompson (Birchtree Station to Wuskwatim Switching Station) and would ultimately be used as outlet transmission once the project was complete.



Operations
Access: Access to the site is by the construction road, which was used to build the project and connect the site to PR 391. The access road is private and is not part of the provincial road network. A security gate near the intersection of the access road and PR391 limits access to the area to those authorized. The site is approximately a one-hour drive from the City of Thompson. There is no landing strip at the site for fixed-wing aircraft; however several landing areas are present to permit helicopter access.

Workforce: The station has approximately 10 staff comprised of the following: operating staff, maintenance staff (electrical, mechanical, utility), support staff (administration, stores) and supervisory staff. The workforce arrive at the Wuskwatim GS from various locations within the province. The workforce is split into two shifts who work an eight days on/six days off schedule, allowing the station to be fully staffed every day between 0700h and 1800h. After hours, the System Control Centre located in the City of Winnipeg monitors alarms within the station and calls out operating staff to investigate any anomalies.

The workers stay at site in dormitories retained following completion of construction of the station. The site is supported by a small on-site kitchen/dining complex and is serviced by the construction water treatment plant and sewage lagoon.

Public Safety: Several safety features were designed into Wuskwatim, including:


 * a water release siren that is automatically sounded before adjusting discharge through the spillway gates to warn the public in the area of the generating station;
 * a boat restraining barrier (safety boom) which is located upstream of Wuskwatim Falls;
 * life rings provided on the spillway, powerhouse intake and tailrace decks;
 * fencing used as a barrier to dangerous areas;
 * signage (printed in English and Cree) for users of the waterway; and
 * security gates which restrict access at the highway access point.

Licenses: Manitoba Hydro operates the Wuskwatim GS on behalf of the WPLP in accordance with the Water Power Act and Environment Act licences issued by the Province of Manitoba. The Wuskwatim GS was the first generating station in Manitoba to be authorized under the Environment Act. For more details on the Wuskwatim GS operations and its effects on the water regime, see Water Regime, Section 4.3.3.6. For further information on the Water Power license, see the Manitoba Government Water Power Licensing website at: http://www.gov.mb.ca/waterstewardship/licensing/water_power_licensing.html.

Mitigation and Rehabilitation
The Wuskwatim GS was designed to be a low impact project and included the following elements:


 * a “low head” design that resulted in minimal flooding;
 * an operating plan that stabilized water levels on Wuskwatim Lake and limits the geographic extent and magnitude of downstream water level and flow changes;
 * an access road that incorporated environmental and cultural considerations in the route selection process;
 * commitment to develop an access management plan; and
 * a commitment to develop an Environmental Protection Plan that assured that all work was carried out in compliance with regulatory requirements, project approvals, and proven environmental protection practices.

Rehabilitation efforts of construction activities at the Wuskwatim GS have been ongoing since 2009, and have consisted of tree planting and seeding which concluded in June of 2015. To date, over 600,000 seedlings have been planted and approximately 198 acres (80 ha) of land has been seeded with native plants. Locations of revegetation include: along the Wuskwatim access road, decommissioned borrow pits, excavated material placement areas, impacted areas around the camp and generating station, and at the Wuskwatim village where cultural plantings took place. The rehabilitation has been a success to date and will continue to be monitored for at least 5 to 7 years under the Terrestrial Effects Monitoring Plan.