Regulation effects on the lower Peace River, Canada

The headwaters of the Peace River, Canada became regulated in 1968 by a maj or hydroelectric facility and associated reservoir located in the Rocky Mou ntains. This paper examines the change to the downstream hydrographs that h ave resulted from regulation, To facilitate the comparison, a naturalized ( without regulation effects) flow regime (1972-1996) was generated using a c ombination of hydrologic and hydraulic flow models. The results showed that even some 1100 km downstream, there have been significant changes to the h ydrograph. Specifically, average winter flows were 250% higher, annual peak s (1-day, 15-day, 30-day highs) were in the order of 35-39% lower, and over all variability in daily flows decreased. Despite the reduction in peaks an d variability, however, the downstream hydrograph is far from flat and has retained the basic shape of the pre-regulation hydrograph. This is primaril y due to the strong influence of tributary inflow below the point of regula tion. Recommendation for improvements to the model and future application o f these data are also discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.