A drought magnitude-based method for reservoir sizing: A case of annual and monthly flows from Canadian rivers

Abstract

Study regionCanadian prairies, northern Ontario, and Atlantic Canada. Study focusA method has been developed to evaluate the reservoir volumes based on the concept of drought magnitude (DM) using annual as well as monthly flow sequences across Canada. The DM based storage volumes have been evaluated using the standardized annual and monthly flow sequences (termed as the standardized hydrological index, SHI) and compared with estimates using the sequent peak algorithm (SPA) utilizing non-standardized flow sequences at varying draft levels. New hydrological insights for the regionIt was found that at the annual scale, 1μ (mean annual flow) level of the draft in SHI (DM based procedure) sequences yielded nearly 54 % of the reservoir volume based on SPA. This volume was considered as an adequate estimate of storage as it corresponded to 96 % μ of the draft level in terms of SPA. At the monthly scale and for the variable mean monthly levels of the draft, SHI sequences yielded reservoir volumes close to 27 % of SPA at the draft of 1 μ. Therefore, MA3 (moving average of consecutive 3 SHI values) was invoked to ramp up the monthly volume to the level of the annual volume of 54 %. Introducing the MA smoothing concept in the DM based procedure for the estimation of reservoir volumes at the monthly scale is the main contribution of the study.