Water Stewardship Information Sources
| Citation | Lewis, A. 2005. Developing measures for the aquatic habiat attribute in BC Hydro's 2005 integrated electricty plan. Prepared for BC Hydro. |
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| Organization | BC Hydro |
| URL | https://www.bchydro.com/content/dam/hydro/medialib/internet/documents/info/pdf/info_iep_piepc_meeting_5_aquatic_habitat_attribute_me.pdf |
| Abstract/Description or Keywords | The environmental objective for the 2005 Integrated Electricity Plan (IEP) defined by the Provincial Committee of the IEP is to incorporate environmental impacts into the consideration of electricity portfolios. The dominant legislation regulating impacts to aquatic (fish) habitat is the Federal Fisheries Act: most new energy resource options have the potential to cause impacts and thus violate the Fisheries Act. Biomass, customer cogeneration, and Power Smart options typically pose no risks to aquatic habitat. However, energy generated from natural gas, coal, large hydro, run-of-river small hydro, wind, and geothermal sources all require infrastructure, including access roads and transmission right-of-ways. In addition, large hydro and small hydro resource options rely on water as the ‘fuel’ for energy generation, which they use non-consumptively, returning the water to the river channel, but nevertheless creating potential impacts to aquatic habitat. These impacts are mitigated through environmental design to meet regulatory requirements, then any residual impacts are offset through the provision of compensation at a rate sufficient to offset the risk of failure in either the assessment process or the provision of mitigation and compensation Despite these environment regulations and the application of best management practices, there are risks that impacts will occur. Potential measures that can describe the risks to aquatic habitats from different resource options are limited by the existing information on the proposed resource options and our knowledge of links between physical changes caused by these projects and the productive capacity of aquatic habitat. These links have been studied and are reported in the scientific literature and in regulatory agency data. The primary measure that can be derived from the IEP resource options database is the surface area of aquatic habitat potentially affected by the development. Surface area is the fundamental metric describing aquatic habitat and is proposed here for use as the quantitative measure to describe aquatic habitat. Qualitative comparisons of the nature of impacts between large and small hydro should also be considered when making decisions based on the quantitative measures. Surface area measures relate primarily to small hydro developments, because these projects have direct effects on aquatic habitat, and also because there are basic physical data available for these projects that can be used to assess impacts. Comparable data are available for relevant aspects of large hydro (Site C) and other resource options. The measures are described and defined in this document, including the equation for calculating surface area, the source of the equation and data inputs, and the assumptions inherent in the calculation. Several variants of the surface area measures calculation are provided; each describes an aspect of aquatic habitat impact expected for a resource option. The surface area measures quantify effects for: dewatering of the diversion section of small hydro projects; backwater effects of large hydro projects; backwater effects at small hydro projects; footprint effects of weirs/dam on all hydro projects; fish presence (a modifier of other impacts); and stream crossings from access roads, transmission lines, and penstocks/tunnels. To calculate the area of aquatic habitat potentially affected and therefore at risk from the development of a resource option, the appropriate measure variants must be selected, combined, and calculated to yield the area affected in hectares (ha). These measures should be applied cautiously, influencing decisions only if qualitative information on potential impacts provided in this document is also considered. There are key questions and data gaps that affect decision making around potential aquatic habitat impacts. Most of these questions and data gaps cannot be addressed within the 2005 IEP time frame; some may be addressed before the start of the 2007 IEP. Three key uncertainties have been identified: 1) accuracy of physical data in the resource database; 2) accuracy of the prediction of aquatic habitat effects from physical data; and 3) comparability of predictions between different resource options. These uncertainties have been acknowledged by defining the assumptions inherent to each measure proposed in this study. For the comparison of small and large hydro projects, a qualitative assessment is provided that evaluates the sensitivity of habitat affected by these resource options and evaluates six aspects of aquatic habitat impact. This provides general guidance concerning the nature of small and large hydro impacts that should be considered along with the quantitative measures of aquatic habitat area that is potentially affected. |
| Information Type | report |
| Regional Watershed | Province |
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| Project status | complete |
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