Framework Testing for Reservoir Design Using Hydrological Simulation Models to Measure Water Demand in Drought-Prone Regions of Indonesia

This research investigates the application of Hydrological Simulation Models (HSM) to assess water demand and design reservoirs in six drought-prone areas of Lombok, West Nusa Tenggara, Indonesia. The island frequently experiences prolonged dry seasons, severely impacting water availability for agriculture, domestic consumption, and industrial use. Using the HEC-HMS model, the study simulated rainfall-runoff processes to estimate water inflows into proposed reservoir designs, based on data collected from local meteorological stations, hydrological measurements, and topographical surveys. These simulations provided critical insights into the seasonal water availability and potential storage capacities required to meet local needs. The results demonstrated that the HSM approach effectively predicted water demand and inflows, allowing for the design of reservoirs that could sustain essential water supply during the dry season. Performance metrics, such as the Nash-Sutcliffe efficiency, indicated a satisfactory agreement between the observed and simulated water flow data, affirming the model's reliability in this context. Although the overall performance was promising, the study revealed the need for further adjustments to the reservoir designs. Specifically, increasing the storage capacity of some reservoirs and optimizing distribution systems were recommended to accommodate seasonal variations and future increases in water demand due to population growth and agricultural expansion. Additionally, incorporating real-time climate data and improving the accuracy of hydrological parameters would enhance the model's precision and adaptability. While these refinements are necessary, the findings underscore the viability of using hydrological simulation models as a critical tool in water resource management for regions facing high drought intensity. The study concludes that HSM can provide a robust foundation for reservoir design, supporting sustainable water supply in drought-affected areas, though continuous monitoring and model updates are essential for long-term success.