https://doi.org/10.1002/rra.3436

Rokaya, P., Peters, D. L., Bonsal, B., Wheater, H., & Lindenschmidt, K. E. (2019). Modelling the effects of climate and flow regulation on ice?affected backwater staging in a large northern river. River Research and Applications, 35(6), 587-600. https://doi.org/10.1002/rra.3436

In cold region environments, ice-jam floods (IJFs) pose a severe risk to local communities, economies, and ecosystems. Previous studies have shown that both climate and regulation affect IJF probabilities, but their relative impacts are poorly understood. This study presents a probabilistic modelling framework that couples hydrologic and hydraulic models to assess the relative role of regulated and naturalized flows on ice-affected backwater staging. The framework is evaluated at an IJF-prone town on the Peace River in western Canada, which has been regulated since 1972. Naturalized flows were generated for the comparison, and ice-affected backwater profiles were calculated along jams of varying length and location and for different combinations of model parameters and boundary conditions. Results show significant differences in backwater staging (~2 m for a return period of T = 1:10 year) between two study time periods (1973–1992 vs 1993–2012) as compared with two different hydraulic flow conditions (regulated vs naturalized), suggesting a larger role of climate than regulation in backwater staging. However, regulation was found to offset flood risk during the 1973–1992 period and exacerbate flood risk during the 1993–2012 period.

https://doi.org/10.1002/rra.3436