Scenario-Based Assessment of Water Supply Capacity for New Reservoirs

Recently, Korea has faced several challenges associated with limited water supply and agricultural water shortages, driven by an increase in the frequency of sudden droughts and a decrease in the water storage rate of reservoirs. Reservoirs play a crucial role in the water supply during periods of drought. Enhancing water supply efficiency through optimized reservoir management is becoming increasingly important for efficient use of the water stored in reservoirs during droughts. Therefore, this study aimed to assess the water supply capacity of new reservoirs based on different scenarios to ensure their functionality during emergencies.

Two scenarios were developed and applied in this study based on the installation and operating conditions of a new water source with a daily capacity of 7,000 m³ to analyze and evaluate its water supply capacity. First, a scenario was developed based on water usage; second, another scenario was created based on precipitation levels. The water supply capacity was then assessed for each scenario.

The reservoir inflow was calculated using the natural flow determined by the soil moisture storage structure TANK model, which is a rainfall-runoff model. The flow rate, used to analyze the water supply capacity of the water source, was derived from the flow rate data comprising 10 years (2012–2021).

In the water supply capacity analysis using the first scenario, the reservoir tracking method was used to analyze the daily time series of the reservoir inflow, evaporation, and water supply volume. Subsequently, an annual assessment was conducted to evaluate the impact of water shortages on the daily water supply. The water supply capacity review estimated that, under the operation condition of using 7,000 m³ of water per day, there would be 367 days (out of a total of 3,652 days) with water shortages over a 10-year period. The normal supply guarantee rate was 89.9%. Furthermore, water usage conditions ranging from 8,000 m³ to 14,000 m³ were applied in succession. The number of days with water shortages ranged from a minimum of 469 to a maximum of 903 days, with the supply guarantee rate varying between 75.3% and 87.2%.

Subsequently, the precipitation scale scenario was implemented based on the operating condition of 7,000 m³ per day, with precipitation levels ranging from 10 mm to 43.5 mm and a water storage rate capped at 100%. The application of the scenario revealed that the number of supply days, depending on the precipitation level, ranged between 6 and 27 days. 

 

Acknowledgements

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)