abstract

Pidekso Dam Reservoir, located in Wonogiri Regency, Central Java, Indonesia is designed to fulfil the needs for raw water, irrigation, and to support a Micro Hydro Power Plant. Additionally, the reservoir aims to mitigate flooding during the rainy season and water scarcity during the dry season in the upstream area of the Bengawan Solo River. This study aims to optimize the water resource management of Pidekso Reservoir using a dynamic programming approach. The method employed is Richard Bellman’s dynamic programming optimization, which takes into account variables such as water availability, raw water demand, irrigation needs, and micro-hydro power utilization. The model was developed as a one-year simulation under various planting start time scenarios to determine the most efficient water allocation.

The optimization results indicate that the most optimal planting start time is in the second period of September. Under this scenario, potential increases in irrigated land area include 1,852 ha for the first rice planting season, 6,105 ha for the second rice season, and 5,776 ha for the secondary crop season. Moreover, the utilization of the Micro Hydro Power Plant also improves, with a dependable flow rate (95%) of 6.911 m³/s. These findings demonstrate that a dynamic programming-based optimization approach can offer a more adaptive and efficient alternative for water resource management.