High Falls and Manitou Falls Hydroelectric Project Description

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5. Potential Effects to the Environment

5.1 Zone of Influence
Due to the run-of-river nature of the proposed development, the zone of the influence for each facility extends from the upstream end of the proposed head pond to the downstream end of the tailrace, where flows from the powerhouse and the bypass reach converge. The actual extent of each facilities’ head pond has not been determined at this time and detailed topographic surveys will be required to confirm the extent. MNR indicated in its Competitive Site Release Package that site development was not to have an impact at Middle Falls, with MNR’s definition of no impact meaning “no change in natural flows and levels as a result of hydro developments at Manitou Falls and High Falls”. Further, it is MNR’s expectation “that there will be no hydraulic or hydrologic effect within the Middle Falls reach as described as north of the upper rapids to below where Otter River flows into the Pic River (specific locations to be determined), at any low or high flows or levels, e.g., flooding from Manitou Falls does not impact on the tail waters of Middle Falls”. The prefeasibility engineering deign presented herein is intended to meet these requirements.
5.2 Potential Effects to the Environment
In order to provide a preliminary identification of the potential effects that the proposed project could have on the environment, the Potential Effects Identification Matrix from the Class EA document (OWA, 2008) was completed (Table 5.1). It is important to note that this table was completed using preliminary information regarding the existing natural and socioeconomic features of the project study area and the preliminary project design to date. The effects assessment will be refined following completion of the baseline studies that are proposed and further refinements to the proposed engineering design of the facilities.

The potential level of effect (positive or negative) is based on the guidance in the Class EA (OWA, 2008). Accordingly, the following definitions of effect were utilized:

  • a ‘nil’ effect would be assigned where there is no effect on that criterion

  • a ‘low’ potential effect would be assigned where the potential impact and/or benefit is considered low or minimal

  • a ‘high’ potential effect would be assigned where the potential impact and/or benefit is believed to be considerable

  • a ‘unk’ would be assigned where the potential effects are unknown or there is insufficient information to assign a potential level of effect with reasonable certainty.

  • a ‘-‘ means a potential negative effect

  • a ‘+’ means a potential positive effect.

    The potential effects are identified as occurring before the implementation of mitigation measures, which would be enacted to prevent or minimize the adverse effects identified in Table 5.1. The ‘Comments, Rationale’ column in the table identifies the potential effects that could occur, and the ‘Mitigation Measures’ column identifies the measures that could potentially be implemented to prevent or minimize adverse effects. Additional mitigation measures that could potentially be utilized are identified in Appendix B of the Class EA (OWA, 2008).

    Table 5.1 [PDF Pages: 4 Size: 100KB]

  • High Falls and Manitou Falls Project
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