Author: Craig Nistor, Violeta Martin
Conference: ICOLD 2017 Annual Meeting
Date: July 3-7, 2017
The 1100 MW Site C Hydroelectric Project involves the construction of a large dam on the Peace River in British Columbia, Canada. The Environmental Impact Statement (EIS) for the project considered technical, socio-economic and environmental aspects and described the predicted effects in the context of previous hydroelectric development and future climate change. Studies were based on long-term field observations and comprehensive modeling. The geomorphology and sediment transport study completed for the EIS predicted changes in channel morphology and suspended sediment loading during construction and operations, which could have ramifications for domestic and industrial water users and aquatic resources. Suspended sediment and turbidity gauging were used to characterize baseline conditions in the Peace River and its key tributaries. A three-dimensional hydrodynamic model was used to simulate suspended sediment dynamics and deposition within the Site C reservoir. During operations the reservoir will trap most of the incoming sediment, with the initial reservoir volume predicted to be reduced by 2.5% after 50 years. The corresponding reduction in mean annual suspended sediment load is predicted to be 54% immediately downstream of the reservoir, but only 2% 300 km downstream at the Town of Peace River, Alberta, because of large sediment inputs from tributaries.
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