J100036, Xeneca Power Development
Surface Water Quality and Fish Sampling Programs
The EAs for four proposed Xeneca facilities on the Kapuskasing River are currently under final regulatory review. The water quality and fish assessment work on these facilities was completed in the fall of 2011, with the exception of some minor data gap filling field work that is being conducted in 2012. Hatch Consultants conducted this work and it is HESL’s understanding from Xeneca that the work has satisfied the recommendations presented in MOE’s draft document titled “Guidance for Conducting Baseline and Post Development Monitoring of Water Quality and Fish Tissue for Proposed Waterpower Projects” (November, 2010) and the intent of MOE’s 2012 draft guidance document. Since the work on the Kapuskasing River facilities was mostly completed prior to MOE’s current guidance document (January, 2012), the recommendations presented herein do not apply to those facilities.
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Background
2.1
Relevance of Monitoring
Surface water quality and mercury accumulation in fish tissue may be affected by any hydropower development, or impounding of surface water, including the impoundments related to the proposed Xeneca projects. Water quality and mercury in fish tissue should be monitored before and after facility development to assess if change is occurring as a result of the development and if this change poses a human health or environmental risk. For example, mercury concentrations are elevated in fish tissue through much of Ontario as a result of atmospheric deposition and natural soil weathering, and a predevelopment baseline of mercury concentrations in fish should be established so that post-development concentrations are not mistakenly attributed to a development involving water impoundment. Conversely, if unacceptable change is occurring as a result of development, monitoring results provide valuable information on the trend(s) of the change relative to pre-development conditions, and informed mitigating action can be undertaken. The monitoring results from existing projects can also be used to design and operate future projects in a way that will have less of an environmental impact.
2.2
Mechanisms of Post-Development Change
Water will be impounded or diverted to some extent as part of each of the proposed Xeneca projects. The extent of impoundment and diversion will vary between the projects depending on the operating regime of the project, the conditions at each facility, and stakeholder as well as environmental requirements. Diversion and impoundment are required to increase the head (fall) of water through the facility to generate power, and water storage is required so that there is a relatively constant water supply through the year for consistent power generation, to maintain flows in the natural watercourse, or a combination of the two. Impounding a river creates an environment in the impounded area that can be more pond- or lake-like than the original river. This results in physical changes to the aquatic environment which may include vertical thermal stratification in the impounded water body, a change in nutrient or metal cycling and concentrations, and/or changes to the fish and invertebrate communities. Similar effects may occur in lakes that increase in depth and surface area as a result of impounding water in their basins, although HESL understands that lakes will not be affected by the impoundments of the proposed Xeneca projects.
Hutchinson Environmental Sciences Ltd. R2012-07-16_J100036_Surface Water and Fish Sampling Rationale_Update to MOE 2012.docx
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