Author(s): Faizal Yusuf; Graham Lang
Linked Author(s): Faizal Yusuf
Keywords: Peak flow attenuation floodplain storage hydraulic modelling regulation naturalization
Abstract: Accurate representation of river corridor geometry is important when assessing flow regime changes along large rivers due to upstream dam regulation. Numerical modelling of the physical processes associated with channel routing and overbank inundation of low-lying areas allows attenuation effects to be simulated that can lead to notable downstream peak flow reduction even as tributaries contribute inflows along the river. For the Peace River, off-channel flooding has been observed in the approximately 100 km long reach referred to as Timber Berth 408 in northern Alberta although the effects on peak discharges have not been previously quantified. In this study, hydraulic modelling is performed for over a 1,100 km reach of the Peace River from W. A. C. Bennett Dam to Peace Point using recently collected bathymetric and topographic data to represent channel and floodplain geometry. Peak flows are found to attenuate by up to approximately 15% in the Timber Berth 408 reach which has implications when evaluating the potential for flooding at the Peace-Athabasca Delta (PAD) located adjacent to the Peace River downstream of Peace Point. To improve the understanding of regulation effects along the lower Peace River, the calibrated hydraulic model is used to develop naturalized open water flows at Peace Point for the 50-year period from 1972 to 2021. The naturalized flows can help to inform the development of future water management action plans. Potential flood impacts at upstream communities will have to be considered if Peace River flow scenarios are to be examined with the objective to promote ecologically beneficial overbank flooding in the PAD.
Year: 2025