Tailoring seasonal climate forecasts for hydropower operations

Abstract

Abstract. Integration of seasonal precipitation forecasts into water resources operations and planning is practically nonexistent, even in regions of scarcity. This is often attributable to water manager's tendency to act in a risk averse manner, preferring to avoid consequences of poor forecasts, at the expense of unrealized benefits. Convincing demonstrations of forecast value are therefore desirable to support assimilation into practice. A dynamically linked system, including forecast, rainfall-runoff, and hydropower models, is applied to the upper Blue Nile basin in Ethiopia to compare benefits and reliability generated by actual forecasts against a climatology-based approach, commonly practiced in most water resources systems. Processing one hundred decadal sequences demonstrates superior forecast-based benefits in 68 cases, a respectable advancement, however benefits in a few forecast-based sequences are noticeably low, likely to dissuade manager's adoption. A hydropower sensitivity test reveals a propensity toward poor-decision making when forecasts over-predict wet conditions. Tailoring the precipitation forecast to highlight critical dry forecasts minimizes this inclination, resulting in 97% of the sequences favoring the forecast-based approach. Considering managerial risk preferences for the system, even risk-averse actions, if coupled with forecasts, exhibit superior benefits and reliability compared with risk-taking tendencies conditioned on climatology.

Balancing Flood Risk and Water Supply in California: Policy Search Integrating Short‐Term Forecast Ensembles With Conjunctive Use

“…Short-term weather forecasts (1-7 days) have commonly been coupled with rainfall-runoff models to forecast flood events and plan operational responses (Saavedra Valeriano et al, 2010). By contrast, seasonal climate forecasts (1-6 month) are more commonly used to inform long-term allocation decisions, for instance, by curtailing releases prior to a forecasted drought to conserve water supplies (e.g., Anghileri et al, 2016;Block, 2011;Golembesky et al, 2009). The combination of short-and long-term forecasts has also proven useful (Denaro et al, 2017).…”

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

“…Combining seasonal meteorological forecasts with hydrological models at continental-scale has provided several continental-scale seasonal hydro-meteorological forecasting systems [22][23][24], such as the European Flood Awareness System [25], the Australian Government Bureau of Meteorology Seasonal Streamflow Forecasts [26], and the National Hydrologic Ensemble Forecast Service, USA [27]. Several studies have demonstrated that a skillful streamflow forecast can enhance the efficiency of water allocation systems to manage the trade-off between hydropower, irrigation, municipal, and environmental services [28][29][30][31]. The potential for employing seasonal forecast in the Yangtze River basin has been investigated in several research studies, mostly through statistical techniques [32][33][34].…”

Valuing year‐to‐go hydrologic forecast improvements for a peaking hydropower system in the Sierra Nevada

“…Several studies of hydropower systems have assessed the improvements in generation and/or revenue from improvements in forecasting local hydrologic state variables, using stochastic dynamic programming [ Stedinger et al ., ; Barnard , ; Tejada‐Guibert et al ., ; Kim and Palmer , ]. Later hydropower studies turned to assessing the value of improvements in seasonal forecasting using climatic teleconnection variables such as sea surface temperatures, in addition to local phenomena, using simulation [ Hamlet et al ., ; Maurer and Lettenmaier , ] and optimization [ Proveda et al ., ; Block , ]. These studies indicate that potential benefits vary widely, depending on local characteristics of the system.…”