Development of reservoir operation rules for environmental water supply

One of the most common methods for operating reservoir systems is to follow pre-established rules that specify allowable release volumes at specific times of the year. In South Korea, traditional reservoir operation rules have primarily focused on human-centric objectives, such as flood control, water supply, and hydropower generation, with insufficient consideration for downstream environmental needs. A key challenge in this context is to develop methods for multipurpose reservoir operation that restore healthy flow regimes in upstream and downstream areas while minimizing disruptions to existing water use benefits. This study proposes water supply adjustment guidelines for multipurpose reservoirs to ensure the sustainable provision of environmental water. The proposed guidelines aim to prevent severe water shortages during drought conditions by gradually reducing allocations for instream flow, agricultural, industrial, and municipal water uses. Recently, the role of multipurpose reservoirs in South Korea has expanded to include the provision of environmental water, with some reservoirs allocating water specifically to improve downstream river water quality. However, specialized water supply adjustment guidelines tailored to environmental water management have not yet been established. This study examines multipurpose reservoirs with environmental water allocations and evaluates the feasibility of monthly environmental water supply plans during drought conditions. A phased water reduction plan focusing on environmental water is proposed, and stage-specific minimum reservoir storage volumes are calculated to meet reliability criteria. Simulated operations are conducted to develop effective and sustainable reservoir operation rules. This research offers a new direction for multipurpose reservoir management in light of the expanding role of environmental water and provides practical management strategies to address the challenges of climate change and extreme meteorological conditions.

 

Acknowledgement

This work was supported by Korea Environment Industry & Technology Institute(KEITI) through Water Management Program for Drought Project, funded by Korea Ministry of Environment(MOE).(RS-2023-00230286)