LGL Limited. February 15, Mr. Trevor Proverbs Site C Clean Energy Project PO Box 2218 Vancouver, BC V6B 3W2

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1 LGL Limited Mr. Trevor Proverbs Site C Clean Energy Project PO Box 2218 Vancouver, BC V6B 3W Second Street Sidney, BC CANADA V8L 3Y8 Tel: (250) Fax: (250) February 15, 2013 Re: Site C Clean Project Review of potential downstream changes on behalf of the Deninu Kue First Nation Dear Mr. Proverbs, On behalf of the Deninu Kue First Nation (DKFN) we are pleased to provide the Draft Technical Memorandum from Kerr Wood Leidal Consulting Engineers on the review of reports relating to the downstream impacts of the proposed Site C Clean Energy Project. In summary, the work to date on identifying potential downstream effects from the Site C appears to be adequate for a project of this magnitude; however, the most significant information gap is the absence of justification for making the boundary of the downstream effects studies as Peace Point, AB. The DKFN is very concerned about the potential impacts from the construction and operation of the Site C project. Changes to the Slave River and Slave River watershed have been noticed by community members since operation of the W.A.C. Bennett Dam and the Peace Canyon Dam and the DKFN is very concerned that these effects will be heightened with the installation and operation of the Site C dam. It is difficult for the DKFN to understand the potential project related effects on the natural systems within its traditional territory when the full consideration of this area is not included in the assessment reports. Cumulative effects are of particular concern to the DKFN as their community lies downstream of major industrial developments. We ask that justification be provided by BC Hydro that explains the rationale behind the selection of the assessment area boundaries with particular interest into why the Peace-Athabasca Delta and Slave River were excluded from the inclusion of downstream effects reporting. Kind regards, Marc d'entremont, PhD Candidate, RPBio. Senior Wildlife Biologist

2 Technical Memorandum - DRAFT DATE: TO: Marc d Entremont, LGL Limited FROM: C. David Sellars, M.Sc., P.Eng., Kerr Wood Leidal Jeff Howard, P.Eng., Kerr Wood Leidal RE: REPORT REVIEW SITE C CLEAN ENERGY PROJECT, POTENTIAL DOWNSTREAM CHANGES On Behalf of the Deninu Kue First Nation Our File Introduction Kerr Wood Leidal Associates Ltd. (KWL) is pleased to provide this review of reports relating to the downstream impacts of the proposed Site C Project. The reports that were reviewed included the following: Potential Downstream Changes. May 4, Prepared by BC Hydro. Site C Operations Study. December 18, Prepared by BC Hydro Generation Resource Management. Downstream Flow Modelling (1D). December 4, Prepared by BC Hydro. Downstream Flow Modelling (2D). December 12, Prepared by BC Hydro. Fluvial Geomorphology and Sediment Transport Technical Data Report. December 18, Prepared for BC Hydro by Knight Piesold Consulting. Reservoir Water Temperature and Ice Regime Technical Data Report. November Prepared for BC Hydro by EBA. Downstream Ice Regime Technical Data Report. December Prepared by BC Hydro Generation Resource Management. Climate Change Summary Report. December Prepared by BC Hydro Generation Resource Management. The first report on Potential Downstream Changes dated May 4, 2012 has been essentially superseded by the recent, more detailed reports. The review therefore focused on the recent reports which were issued in November and December The scope of work for the review was as follows: Comment on whether the information presented and the methods used are adequate for a project of this magnitude; and Identify any information gaps that should be included in the report.

3 2. Environmental Impact Statement Guidelines Guidelines for the Environmental Impact Statement (EIS) for the Site C Project were issued in September The EIS Guidelines were issued by the Executive Director of the Environmental Assessment Office of British Columbia and, in accordance with Section 19 (2) of CEAA, by the Minister of Environment of Canada, in order to set out the scope of the factors to be taken into consideration in the environmental assessment of the Project. A key aspect of the guidelines is the extent of the environmental assessment in downstream watercourses. The Guidelines document states: The Proponent proposes that the spatial boundary would be from Peace Canyon Dam downstream to Peace Point, Alberta. There is no justification provided for this proposed spatial boundary and no further discussion in the Guidelines document. The implication is that the regulators have accepted the proposed boundary and all of the documents reviewed include this downstream boundary or a boundary slightly further upstream. As a consequence none of the documents prepared by BC Hydro on the downstream impacts of the Site C Project address potential impacts downstream of Peace Point on the Peace River. 3. Review of Reports This section of the technical memorandum addresses each of the reports reviewed in subsections corresponding to the major issues. 3.1 Operations Study The Site C Operations Study simulates flow releases to the Peace River from the proposed Site C Dam and compares them with the flows that would have been released from the existing Peace Canyon Dam under the same electrical load conditions. The Operations Study is thus critical to the examination of downstream impacts as it provides information on how the pattern of flows in the Peace River would change with the Project. The Operations Study uses BC Hydro system models to simulate how the Site C dam would be operated. The models optimize the operation of the entire BC Hydro power system to meet electrical system loads while seeking to maximize the operational value of the generating resources subject to dam safety requirements, physical capability, flood and ice control and regulatory requirements. The models are thus extremely complex and are used on an everyday basis by BC Hydro to guide the operation of the system. The validity of the models as applied to the Site C project was investigated by examination of the model outputs. The operation of the Site C generating station would be coordinated with the operation of existing facilities upstream on the Peace River as well as other available system resources to meet provincial demand for electricity. Accordingly, Site C reservoir releases follow the same general pattern as the provincial demand for electricity. Generally the pattern is higher during the winter and lower during the summer on a seasonal basis, higher during weekdays and lower during weekends on a weekly basis, and higher during daylight hours and lower during late night hours on a daily basis. Compared with flow conditions without the Site C project there are generally increased flow fluctuations which would be expected with the increased generation capacity on the Peace River encouraging more use of the Peace River resources. The simulated operation of the Site C Reservoir shows that the Site C reservoir would be 2

4 operated within the top 0.6 m over 99 per cent of the time. This is consistent with the objective of maximizing generation as Site C produces more power at higher reservoir levels. It is clear from this review that BC Hydro has used its most comprehensive and complex models for the Operations Study which are currently used by BC Hydro to manage their power generation system. No information gaps were identified. 3.2 Downstream Flow Modelling The downstream flow modelling was carried out by BC Hydro to investigate changes in flows with Site C in operation. Flow inputs to the modelling were provided from the Operations Study. Two models were used; a one dimensional model, MIKE 11 for the entire reach understudy and a two dimensional model Telemac2D for investigations of specific reaches. Both models are considered state of the art in river modelling. The models required calibration which involves adjusting parameters to get the best model fit to observed data. Based on the information presented the calibration procedures were thorough. However, information was not provided on model validation. Validation compares simulated model output with observations using data not used in model development. The validation process ensures that the model will provide valid results when used for different flow conditions than those used during the calibration process. Regarding the changes with flow releases from Site C compared with the current situation, the MIKE 11 model shows the progressive decreasing effect of the flow changes downstream. This is due to progressive attenuation of the released discharges and increasing contributions from tributary flows. Information on flow and water level changes is provided to Peace Point on the Peace River. The methods used are adequate for a project of the magnitude of Site C for the reach of the river to Peace Point. However, additional information should be provided on model validation. No information is provided on changes to downstream flows during construction and reservoir filling apart from stating that flows would always exceed the existing Peace Canyon minimum licensed flows. During construction, changes to the normal regulation of the river may be required by adjusting releases from the Williston Reservoir. The rate at which the Site C reservoir would fill would depend on releases from the Williston Reservoir, local inflows and downstream releases which could exceed the minimum licensed flows depending on downstream conditions. Additional information should be provided on downstream flows during construction and reservoir filling. 3.3 Fluvial Geomorphology and Sediment Transport The fluvial geomorphology and sediment transport studies involved three major steps: Modelling the sediment characteristics of the proposed Site C reservoir; Estimating the resulting outflow of sediment from the dam; and Assessing the effects downstream with the changes in sediment regime. The study addressed key phases of the Project including the channelization stage when the river is constricted by lateral coffer dams, the diversion stage when the river is diverted to allow the dam to be constructed, reservoir filling and the operations phase. Each phase results in different changes to the downstream sediment regime. The report addresses the fact that there has been significant change in the fluvial geomorphology of the Peace River since construction of the Bennett Dam in Prior to hydroelectric development in 1967, Site C Downstream review 3

5 fluvial geomorphology and sediment transport regime in the Peace River were naturally dynamic due to the localized nature of sediment inputs from tributaries and valley-wall landslides, and due to a seasonal range in flows. Since 1967, fluvial geomorphology and sediment transport regime in the Peace River have been in a state of adjustment to the regulated flow conditions. The potential changes in fluvial geomorphology and sediment transport regime related to the Project were considered in the study in light of the fact that the baseline conditions in the Peace River are both naturally variable and are undergoing a long-term response to regulation. Thus, the changes that could be attributed to the Project are different from the changes that would result from the current, ongoing response to river regulation in the absence of the Project. River regulation has contributed to an imbalance between tributary bedload inputs and downstream bedload transport in the Peace River. The consequence has been fan/delta progradation at tributary confluences and localized aggradation in the Peace River immediately downstream of the tributary confluences as the incoming bedload accumulates in the Peace River channel. The report includes a series of channel change maps showing active and inactive channel zone changes from 1964 to The channel changes that were documented indicate extensive vegetative encroachment onto formerly unvegetated bars, as well as in secondary channels. Field observations indicate that since 1967, fine sediment has accumulated in secondary channels and on some bar surfaces over gravel and cobble bed material. An advanced three-dimensional model was used to simulate the erosion of the reservoir margins including wave action and the trapping of sediment inflows to the reservoir. It was found that suspended sediment in the modelled reservoir outflows would consist almost entirely of clay-sized particles. All sand settles close to the site of input, and almost all of the silt settles in the reservoir as well, except during large tributary inflow events. The predicted 10-year average suspended sediment composition for reservoir outflows would comprise 0% sand, about 2% silt, and 98% clay. Compared with current conditions, in the first decade of operation there would be a 100% reduction in sand, 98% reduction in silt, and 21% increase in clay (due to new shoreline sources that are expected to decrease with time). The relative magnitude of reservoir-related changes in suspended sediment concentration are greatest between Site C and the Pine River confluence, then diminish with the water and sediment inputs at each successive tributary confluence. The relative reduction in mean annual suspended sediment load would reduce in a downstream direction, from 54% at the Site C dam site to 2% at the Town of Peace River and 2% at Peace Point. These changes are relative to the current conditions following construction of the Bennett Dam The report concludes that the Project would not influence the natural erosion and deposition patterns or ongoing channel changes that have occurred over the past four decades in response to upstream flow regulation. The latter changes are due to the regulated flow regime of the Peace River (related to past hydroelectric development), compared to which the additional flow regime modifications imposed by the Project would be small. The interruption of bedload transport by the Site C dam would only influence the local downstream area. Ongoing vegetative encroachment onto bars and into secondary channels, and ongoing channel aggradation below the Pine River and other tributary confluences, are expected to continue in the future unrelated to the Site C Project. The Fluvial Geomorphology and Sediment Transport report is a comprehensive document and is well supported by data in appendices. The methods used are adequate for a project of the magnitude of Site C for the reach of the river to Peace Point. No information gaps were identified. 4

6 3.4 Ice Regime Simulating the downstream ice regime in the Peace River involved three key steps: Modelling reservoir temperatures and outflow temperatures in the Site C reservoir; One-dimensional modeling of the downstream ice regime in the Peace River; and Simulation of thermal ice growth at selected locations. A three-dimensional circulation model, H3D, was used to simulate temperatures and ice cover for the proposed Site C reservoir. The model computes a time-varying, three-dimensional velocity and temperature field, and also simulates time-varying and spatially-varying ice coverage on the reservoir. To develop a model that would predict realistic conditions in the Site C reservoir, a model of Dinosaur Reservoir, (Peace Canyon Dam) a nearby water body, was developed, calibrated, and validated first. The model code and parameters developed for Dinosaur Reservoir were then used for the Site C reservoir. The model for Dinosaur Reservoir was calibrated and validated against water temperature measurements and predicted outflow water temperatures within 0.2 C. The model accurately represented the ice cover observations in Dinosaur Reservoir. The river ice studies were carried out using two models, a one-dimensional model for the Peace River from the Project area downstream to Fort Vermillion and a second model to simulate the growth of ice cover at selected locations. The one-dimensional model CRISSP (Comprehensive River Ice Simulation System Program) was used to simulate most of the ice processes and to quantify frazil ice generation, suspended and surface ice concentrations, total ice thickness, ice affected water level, ice front progression rates and thermal recession rates of the ice cover. Surface ice concentrations from CRISSP were used to determine the cessation of ferry operations. Ice front positions from CRISSP were used as input for the start of the growth of thermal ice in PRTIGM (Peace River Thermal Ice Growth Model). PRTIGM was used to simulate thermal ice growth at selected locations to determine when the thermal ice cover would be thick enough for ice bridge construction, and to determine when BC Hydro could resume normal operations after flow control was in place for managing freeze-up water levels at the Town of Peace River. Both river ice models have been in use operationally by BC Hydro for a number of years and have been well calibrated and validated. The operational use is directed towards modifying flow releases (controlled flows) to influence the degree of ice jam flooding at the town of Peace River. The report is focused on the changes to these controlled flows that would occur with the Site C project and changes to the timing of freeze-up, timing of break-up and the formation of ice bridges. Changes to the progression of the ice front over the winter period are also documented in the report. The analysis shows that there would be no changes to the ice regime at Fort Vermillion and it is thereby assumed there would be no changes downstream of Fort Vermillion. The CRISSP model is not suitable for modelling ice jams and the report addresses ice jams in a qualitative way. It is stated that high water levels at break-up at the Town of Peace River would remain unchanged from existing conditions as they are a function of the Smoky River breaking up dynamically into an intact Peace River ice cover. The modelling shows that the Project does not change the average timing of the thermal break-up of the Peace River ice cover at the Town of Peace River and it was therefore assumed that peak break-up water levels would not change from those experienced under existing conditions as a result of the Project. Site C Downstream review 5

7 The models and methods used are adequate for the Site C project and no information gaps were identified. 3.5 Climate Change The climate change studies involved three key steps: Analysing historical climate and flow trends. Downscaling global climate model output to provide site-specific values for hydrologic modelling. Using the projected climate in a hydrologic model to predict future flows. Historical trends in inflows were analyzed by combining a relatively simple linear technique with direct estimation of signal-to-noise ratios. The analysis was applied to monthly and annual mean inflow data over a common period of record for all basins. The result identified changes in both seasonal runoff patterns and annual net water supply. Observed trends in precipitation, temperature, and reservoir inflows, i.e., rates of change, were derived by linear trend fitting. The Pacific Climate Impacts Consortium in collaboration with BC Hydro carried out the global climate model downscaling. To generate daily time series of precipitation and temperature, global climate model climate projections were downscaled statistically using the Bias-Corrected Spatial Disaggregation approach. Mean daily temperature was used as a driver, while minimum and maximum temperatures were derived indirectly from the climatological temperature range. The Variable Infiltration Capacity Model, a spatially distributed physically based macroscale hydrological model was used for all future hydrological projections. The Variable Infiltration Capacity Model was applied at a resolution of 1/16º (~ 30 km 2 ) and was run at a daily time step. Calibration of the six selected parameters was performed using a multi objective global optimization algorithm. Automatic calibration was based on the comparison of observed to simulated discharge in the time period at 23 calibration sites within the study area. The model calibration was tested on discharge data between 1985 and Model calibration and testing was based on two performance measures: the Nash-Sutcliffe Efficiency and the per cent volume bias. The Nash-Sutcliffe Efficiency is the most commonly used performance measure in hydrology. Both the Nash-Sutcliffe Efficiencies and the volume bias indicate that the model was well calibrated and validated. The approaches and methods used in the climate change analysis represent the current state-of the art for this type of analysis. The hydrology model used for projections of future flows under climate change was well-calibrated and validated. No information gaps were identified. 4. Conclusion 4.1 Adequacy of Information Presented and Methods Used In general the information presented in the reports reviewed is adequate for a project of the magnitude of the Site C Project. The approaches and methods were of a standard to be expected for these types of analyses. A number of different models were used in the studies and they are all appropriate for studies of this complexity. The results of the models are well presented in graphs, tables and maps. 4.2 Information Gaps The most significant information gap is the absence of a justification for the downstream extent of the studies at Peace Point. Rather than assuming that the reader will infer that the study extent is 6

8 appropriate, there should be a rationalization presented for the choice of downstream boundary. This assessment should include the recognition that the Peace-Athabasca Delta, which is located less than 50 km downstream of Peace Point, is the largest boreal delta in the world and has been designated a wetland of international importance under the Ramsar Convention because of its ecological and habitat value. The water regime of the Peace-Athabasca Delta has been influenced by the effects of flow regulation on the Peace River (Prowse et al, 2006) which enhances the importance of providing a justification for the boundary selection even though control structures constructed in the delta in the 1970s have partially countered the major effects of upstream flow regulation A second identified information gap is related to the development of the models used to simulate downstream flows with and without the project. The models used for the downstream flow analyses were well-calibrated. However, additional information should be provided on model validation for the two models used for the downstream flow analyses. Finally, no information is provided on changes to downstream flows during construction and reservoir filling apart from stating that flows would always exceed the existing Peace Canyon minimum licensed flows. During construction, changes to the normal regulation of the river may be required by adjusting releases from the Williston Reservoir. The rate at which the Site C reservoir would fill would depend on releases from the Williston Reservoir, local inflows and downstream releases which could exceed the minimum licensed flows depending on downstream conditions. KERR WOOD LEIDAL ASSOCIATES LTD. Prepared by: Prepared by: C. David Sellars, M.Sc., P.Eng. Senior Water Resources Engineer Jeff Howard, P. Eng. Project Manager DS/JH/am Reference Prowse, T.D., Beltaos, S., Gardner, J.T., Gibson, J.J., R.J. Granger, Peters, D.L., Pietroniro, A., and Romolo, L Climate change, flow regulation, and land-use effects on the hydrology of the Peace-Athabasca-Slave system; finding from the Northern Rivers Ecosystem Initiative. Canada s Ecosystem Initiative Special Issue, Journal of Environmental Monitoring and Assessment, 113(1-3): Site C Downstream review 7

9 Statement of Limitations This document has been prepared by Kerr Wood Leidal Associates Ltd. (KWL) for the exclusive use and benefit of the intended recipient. No other party is entitled to rely on any of the conclusions, data, opinions, or any other information contained in this document. This document represents KWL s best professional judgement based on the information available at the time of its completion and as appropriate for the project scope of work. Services performed in developing the content of this document have been conducted in a manner consistent with that level and skill ordinarily exercised by members of the engineering profession currently practising under similar conditions. No warranty, express or implied, is made. Copyright Notice These materials (text, tables, figures and drawings included herein) are copyright of Kerr Wood Leidal Associates Ltd. (KWL). Any use of these materials without the written permission of KWL is prohibited. Revision History Revision # Date Status Revision Author 0 Jan. 18, 2013 DRAFT DS / JH 8