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August 18, 2010 - The final ER is in progress and an updated schedule with key delivery dates will be posted shortly on this site.
March 1, 2010 - OPEG has developed a conceptual 3D interactive model based on preliminary designs. View the 3D Model (Adobe Flash Required)
March 1, 2010 - The inspection period for the High Falls Draft Environmental Report (ER) has closed. OPEG is working toward publishing the final ER and anticipates it's release in the Spring of 2010. OPEG would like to thank all those that gave input into this project.
The proposed development consists of one 6.4 MW hydroelectric generating station (GS) situated at High Falls. The generating station will operate as a run-of-river plant within the historic fluctuation bands of Bill and Little Eva Lakes. The site will develop approximately 7meters of maximum gross head while causing minimum disruption to water quality. The development requires water diversion from High Falls/Bill Lake to an intake canal. The diversion mechanism will consist of one concrete weir, totalling approximately 150m in length, positioned on a natural shelf upstream from the crest of the falls. The proposed weir will be of varying section heights, creating a consistent crest elevation of EL.352.30m. A second weir, with an integrated fish migration system, will be constructed across the Back Channel to Eva Island approximately at the bridge crossing. An intake canal adjacent to the falls at the site of the existing portage route will carry flows from Bill Lake to the powerhouse and spillway. The intake, powerhouse, and spillway will be located on the portage trail, following the natural topography of the site. The outflow of Bill Lake will therefore have three outlets; the natural flow over the weir and falls, down the Back Channel and through the intake canal to the powerhouse and spillway. Upon exiting the powerhouse and/or spillway, the water will enter the tailrace channel, which will extend to re-join the Namakan River, downstream of the falls. Cofferdams will be required to prevent flooding of the work site, and damage to the aquatic environment from sedimentation and contamination during construction of the powerhouse, headworks and tailrace channels. Construction of these works will require excavation of overburden and bedrock, resulting in a significant volume of rock generated as well as overburden. Excavated rock will be used in the construction of the upstream and downstream cofferdams, as well as for concrete aggregate and road topping material.
Ancillary works include rock removal of identified constriction points approximately 250m downstream of High Falls, and at the outlet of Little Eva Lake. These excavations will enhance generating capacity at High Falls GS by mitigating turbulence, or tailrace effects and reducing backwater effects following high-water events. Some in-stream bedrock removal is planned downstream of High Falls, which will moderately increase the streambed cross-section, thereby reducing velocities and offering a threefold benefit to the undertaking: enhancement of existing spawn habitat through improved access opportunities; creation of new spawning habitat by dressing the excavation site with preferred substrates; and improved turbine efficiency due to reduced velocity
The project will require a combined access road, and 44kV power corridor right-of-way from the High Falls facility to Flanders Road. The 2.3 km long power line will generally follow the alignment of the access road, extending south approximately 1.2km over Eva Island and a further 1.1 km over co-managed Crown lands. A new connection point would be constructed to tie into the existing 25kV line along Flanders Road, which will be upgraded to 44kV. A step-down transformer will be installed to maintain the existing 25kV supply to the Lac La Croix Community. The undertaking will also include the construction, operation and maintenance of a bridge across the Back Channel to allow road access to the High Falls facility. The right-of-way will conform to the Ontario Ministry of Natural Resources’ Environmental Guidelines for Access Roads and Water Crossings (MNR 1995).
Existing access trails into Hay Rapids and other selected points along the river may be maintained to allow equipment access for channel improvement work, stumping and shoreline erosion protection. These trails will be encouraged to naturalize following construction activities.
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