Ensemble hydrological forecasts for reservoir management of the Shipshaw River catchment using limited data

Abstract

Many hydropower companies continue to rely on expert judgment to manage the operations of their reservoirs. Decision-support systems, composed of a hydrological forecasting system and a reservoir model, can ensure that reservoir operation objectives are attained more effectively than by relying solely on expert judgment. In this study, a simple ensemble inflow forecasting system coupled with a reservoir model is developed and the proposed model-based operational water management decisions are compared with those based on expert judgment for the Shipshaw River in Quebec, Canada. Given that no natural streamflow records are available for the Shipshaw River, the HEC-HMS hydrological model is calibrated using a regionalization method based on physical similarity. The calibrated hydrological model is fed by ensemble meteorological forecasts that include 20 members, with a 10-day horizon and a 6-hour time step. The proposed decision-support system can help avoid small flooding events while potentially improving energy production by 2 to 60% for this case study. The proposed forecasting system also allows water-resource managers to anticipate events with a greater lead time.